adio-Electronics

FOR MEN WITH IDEAS IN ELECTRONICS

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In Solid -State Circuit

TRY YOUR CURVE TRAC

Lou Garner's

STATE OF.SDUD-STATE
Bob Scott's
TECHNICAL TOPICS

Jack Darr's
TV SERVICE CLINIC

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ri

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If You Want

To

Get Ahead in Electronics,

Get ON TARGET Now!
Are you planning your future or just drifting into it? Don't depend on luck; take
aim. Prepare yourself for the future by
getting plenty of "know how." Be ready
to take advantage of opportunity when it
knocks. Get more real education in electronics now.

GRANTHAM TRAINING
PREPARES YOU

Grantham School of Engineering

is a

college -level institution, offering technical and engineering programs in electronics mainly by correspondence. The School
is authorized (by the California Department of Education) to grant academic
degrees, is approved under the G.I. Bill,
and is accredited by the Accrediting
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Get Your
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You can advance your career in electronics mainly by

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STUDYING AT HOME

for your F.C.C. license, and the Degree

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RE -11 -72
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Please send me your free Bulletin which explains how
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Grantham School of Engineering

am

Established in 1951

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beginner in electronics.

am an electronics technician.

Name

Telepiu ne:

Address

(2/3) 469-7878

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card

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State

NOVEMBER 1972

Zip

RADIO -ELECTRONICS

There's an

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Imported or Domestic!

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Radio -Electronics
F

O R

M E N

T H

D E A S

ELECTRONICS

November 1972

TEST

EQUIPMENT

BUILD THIS ONE

GENERAL
ELECTRONICS

26
41

Equipment Report
Heathkit 10 -105 dual -trace triggered scope

ON THE COVER
A GOOD PORTION of the R -E Digital Grinchwal System is shown on

Using The Vectorscope

How it works and some new ways to use it.
by Robert G. Middleton

54

Equipment Report
International Crystal FM- 2400 -CH frequency meter

55

Generator Applications
Nine ways to use an rf generator; also how to build
portable unit. by Jim Huffman

small

62

Using A Solid-State Curve Tracer

A must "tool" for modern servicing; you have to understand
it to use it effectively. by Mannie Horowitz

33

Grinchwal Digital Instruments

One mainframe and several plug -ins form a complete digital
test equipment system. by Don Lancaster

Looking Ahead
Tomorrow's news today. by David Lachenbruch

37

VW's Self- Diagnosis Computer

Built -in electronic monitoring plugs into a computer for a
rapid and complete rundown of your car's performance.
by Fred W. Holder

to

R -E

52

Technical Topics
Unusual i.f. sweep generator, micropower on -off indicator,
and versatile lab -power supply are among the subjects

explored. by Robert

F.

DEPARTMENTS

e
e

..

'
.

ro

it4

44

e
e

88

Appliance Clinic
Technicians guide to the clothes dryer. by Jack Darr

50

Step -By -Step Troubleshooting

Inside the sound modules. by Art Margolis

69

Service Clinic
Imagination, the technician's most important tool.
by Jack Darr

70

Reader Questions
R -E's Service Editor solves reader problems.

Radio-Electronics is indexed in Applied Science & Technology Index

and Readers Guide to Periodical
Literature.

Circuits

83

New Products

16

Letters

92

Next Month

New

111

Reader Service Card

91

New Books

95

Technotes

86

New Literature

90

Try This

Timely

Hugo Gernsback (1884 -1967)

founder
M. Harvey Gernsback, editor -in -chief
and publisher
Larry Steckler, editor, CET
Robert F. Scott, W2PWG technical editor, CET
Jack Darr, service editor
Louis E. Garner, Jr., semiconductor editor
I. Queen, editorial associate
Matthew Mandl, contributing editor
David Lachenbruch, contributing editor
James A. Gupton, Jr., photographic electronics
Vincent P. Cicenla, production manager
Nancy Gipson, production assistant
H. Matysko, circulation
Cover photograph by Walter Herstatt
Cover design by Marius Trinque

100

&

THE CURVE TRACER CAN BE VALUABLE to

all who work in electronics. But first you must
know how it works and what it can do. For a
truly important article
see page 63

Scott

State Of Solid -State

Telephone answering machines; a low -power drain semiconductor and several other new devices. by Lou Garner

TELEVISION

MIN=

Editors Earn CET Certificates

45

59

this month's front cover. You can

see the mainframe, described in
this issue, along with several plug ins. For those who wonder how
the picture was made, our photographer, Walter Herstatt set the
plug -ins on the colored burlap
background. He then placed a
sheet of glass over the top of modules and positioned the main unit
on the glass. This resulted in the
floating in space look of the unit.

Radio-Electronics, November

1972. Vol 43, No. 11

Published
monthly by Gernsback Publications, Inc., 200 Park Avenue South, New
York City 10003 Second -class postage paid at Nevi York, N Y. and
additional mailing office. One-year subscription rate. U.S.A., U S. possessions and Canada, $7. Pan -American countries, $8. Other
countries. $8 50 Single copies 608. 1972 by Gernsback Publications, Inc All nghts reserved. Printed in U.S A.

Subscription Servie: Mail

all subscription orders, changes. correspondence ana Postmaster Notices 01 undelivered copies (Form 3579)
to Radio-Electronics Subscription Service, Boulder, Colo. 80302.

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

looking ahead
An LP videodisc
A new development in the

videoplayer field has the television industry buzzing, and

there are some predictions
that it could be as revolutionary as color TV. Whodunit?
RCA. At press time, RCA was
making no comment except to

concede that the development

did indeed exist and that our
description was substantially
correct.
RCA has quietly been demonstrating to a few select television set manufacturers and
others in the TV industry a
long- playing color videodisc
system that is said to use an
inexpensive player and low cost conventional -appearing
records. We have not seen the
device, nor has any representative of the press. But we have
talked with enough qualified
engineers (none from RCA)
who have witnessed a demonstration to feel that it is of ma-

jor significance as a potential

new home product.
What RCA is demonstrating
to the select few is a device
that resembles a conventional
phonograph, plays 12 -inch
discs, but is attached to a color
TV set and is capable of playing 20 minutes of color picture
plus stereo sound from each
side of the disc -a total of 40
minutes for both sides. It is a
playback -only device and cannot make recordings. Radio Electronics readers learned
about the German -British color
videodisc developed by A.E.G.
Telefunken and Decca in last
December's issue. It is a major
technical achievement, using a
cushion of air to suspend a
flexible disc, that whirls at
1800 rpm and uses a specially
designed "pressure stylus" to
read out the picture. A single
disc will play for five minutes.
What is dramatic about
RCA's development is its differences from the TelefunkenDecca system and its simIfarities to standard audio disc

RADIO -ELECTRONICS

equipment. It spins at 400 to

500 rpm, and apparently uses

the traditional needle -ingroove pickup system. The

discs are rigid, rather than
flexible, and are pressed in the
conventional record -pressing
manner. Those who have witnessed RCA's demonstration
were impressed with picture,
color and sound. The eventual

retail price of the playing

equipment is expected to be
somewhere under $400 -perhaps far under -with discs
costing less than a dollar for
material and pressing. This
compares with $35 or more for
an hour's worth of blank video
tape.
Although RCA's system is
still in the developmental
stage, the target date for marketing is understood to be late
1974, which will also mark the
tenth anniversary of the start of
work on the system at the RCA
Laboratories in Princeton, N.J.
What is the secret? Nobody is
saying. But in this day of sophisticated computer memories, it would be ironic indeed
if the phonograph disc -an invention of the 19th centuryturned out to be the most practical information -storage medium.

cast band and relieving them

of the responsibility to build
sets which can adequately
tune to stations which aren't
there. The EIA argues that reducing the size of the uhf band
would make it easier to build
tuners and help improve tuning
accuracy by reducing the compromises needed to span the
huge uhf band with one tuning
instrument.

Cable TV's growth

More than 10% of the na-

tion's homes are now receiving

television by cable, according
to figures in the latest issue of
Television Factbook, which
keeps track of such things. As
of the start of this year, the
publication's statistics show, 6

million homes were connected

to cable systems, an increase
of 700,000 during 1971. On
March 31, 1972, there were
2,839 CAN systems in operation, the average system serving 2,272 subscribers. Fewer
than half of the existing systems merely supply subscribers with programs picked
up from TV stations, and 594
originate their own programming -live, film and /or videotape. An additional 920 have

"automatic

Smaller uhf band?

Under federal law, all television sets manufactured must
be able to tune all 70 channels
from 2 through 83. But in 1970,
the FCC turned over the top 14
uhf channels -69 through 83to the land- mobile radio services. The only broadcast facilities still occupying these
upper channels are about 800
low- powered translators, that
have been given FCC permission to move to lower
frequencies. Television set
manufacturers, through the
Electronic Industries Association, now have petitioned the
FCC to cut the knot once and
for all, lopping the top 14
channels from the TV broad-

originations"

only -channels served by automatic time and weather reports, news tickers and the
like. Some 210 systems insert
commercials in their own programming. The country's largest systems are in San Diego,
with 65,000 subscribers as of
March 31; New York City,
45,000; Northampton, Pa.,
45,000; a second New York
system with 43,000; Altoona,
Pa., 42,500, and Allentown,
Pa., 38,275.
Its no accident that Pennsylvania is so heavily represented among the largest sys-

tems- that's where CATV

started, as a means for bringing clear reception to cities in
areas where mountains made
it impossible to receive satis-

NOVEMBER 1972

www.americanradiohistory.com

factory direct off-the-air television.

It adds up
Soon everybody will have
one and manual arithmetic will
be obsolete. Or so it seems,
with prices on electronic calculators dropping like autumn
leaves. The pocket calculator
has now moved into the home
product category, as the result
of rather startling prices. As
little as a year ago, $200 or
$220 was a bargain price for a
calculator. Today, thanks to a

single -chip MOS, calculators

are coming within the range of
housewives and students.
American, not Japanese,
manufacturers have taken the
lead in bringing calculator
prices down into the consumer- product range. Bowmar
Instrument Corp., the biggest
manufacturer, has sold about
250,000 pocket units with LED
readouts, with a list price of
$179. North American Rockwell has been making units
with liquid -crystal readout designed to sell at about $100.
Texas Instruments, which
makes the MOS chip, has a
pocket unit at $150 and will
soon introduce a desk -top
model at about $85. The Japanese, whose prices on calculators has been higher than
those of the lowest -priced
U.S. -made models, have now
begun to fight back. Sharp,
probably the leading Japanese
calculator manufacturer, is
readying an under -$100 model
for the American market. But
the lowest price yet is from
Casio of Japan, which has introduced a six -digit model on
the American market at under
$60 retail. The same unit sells
in Japan at less than $42. Next
year it's forecast that some

pocket calculators will

be

available at less than $50 in

the United States.
by DAVID LACHENBRUCH
CONTRIBUTING EDITOR

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NOVEMBER 1972

RADIO- ELECTRONICS

new s timely
Lithium tantalate crystals
to improve communications
A new man-made crystal, now in production at Western Electric's Merrimack
Valley Works in Massachusetts, the first
practical alternative to quartz for use in
communications equipment, may improve
and simplify crystal filters. It may also find
use as a light modulator and as a detector
of infrared light frequencies.
Piezoelectric crystals (crystals that
deform under an applied voltage and that
produce a voltage when stressed mechanically) are widely used as filters in communications equipment. The bandwidth of
quartz crystals, heretofore the universal
material for crystal filters, is limited by a
weak electromechanical coupling characteristic; its efficiency in converting mechanical to electrical energy or the reverse is not as high as might be desired.

In the 5 -to -1

mode, two passes of the

scanner take full -size views of right or left
lateral or of back or front, plus minified
whole -body views. In the 2 -to -1 mode,
substantial film savings are possible; it is
necessary to load film into cassettes only
once instead of four times to obtain a
complete photo record.

NANCY BRACKETT, former Miss Massachusetts. holds a film demonstrating the new X -ray
technique.

The system is completely compatible

with the company's single and dual -head
nuclear scanners and is available as optional equipment.
CRYSTAL MAKERS AT WORK -Albert Ballman
of Bell Laboratories and David Rudd of Western
Electric Co., with the crystal pulling machine.

Lithium tantalate has an electromechanical coupling constant five or six

times better than that of quartz, according
to Albert Ballman of Bell Laboratories,
who developed the new crystal. Its tern perature- frequency characteristic compares favorably with that of quartz, and it
has low impedance, high Q, minimum coupling to unwanted modes, good machinability and low water solubility.

Practical superconductivity with

new cryogenic material?
Superconductivity has been reported
at temperatures above 20 Kelvin ( -254
C) by researchers at the RCA laboratories
in Princeton, N.J. This research advance
may make superconductive electric motors, generators and transmission lines
possible. The material that retains its su-

perconductivity at these "high" temperatures is a compound of niobium and gallium.

A superconductor, produced by cool-

ing a metal to a temperature near absolute

zero, has no resistance. Thus it can carry
practically unlimited amounts of current.
Unfortunately, a slight increase in tem-

perature destroys superconductivity, as

does a magnetic field above a certain
strength.
Superconductivity has in the past
been obtained only a very low (cryogenic)
temperatures-a few degrees above absolute zero. Cooling to such low temperatures is expensive -the new material may
make a cost reduction of 75% possible.
The new compound not only retains
its superconductivity at relatively high
temperatures, but also in magnetic fields
far stronger than is possible with other superconducting materials.
It is possible that practical niobiumgallium superconductive systems can be
made to operate efficiently in magnetic
fields greater than 100 kilogauss and at
temperatures higher than 14 K. That temperature can be reached with liquid hydrogen refrigeration, instead of the much
more costly helium refrigeration required
for lower temperatures.
Experiments with superconducting
transmission lines have already been
made, and a variety of applications may
become practical with the new, more economical, approach to superconductivity.

Communications
Honored

Technologist

"Minified" X -ray pictures

possible with new technique
A new minification system that permits taking pictures of the whole human
body on a single piece of standard X -ray
film has been announced by the Medical
Electronics Operation of the Raytheon
Co., Waltham, Mass. This will make faster
and more accurate diagnoses possible.
The equipment provides for two
minification levels: 5-to-1 for whole -body
scanning and 2 -to -1 for individual organs.

RADIO -ELECTRONICS

Dr. GEORGE

W.

WEBB, ACHIEVER

of the

breakthrough in cryogenic research, continues

to search for higher temperature superconductors.

NOVEMBER 1972

www.americanradiohistory.com

Dr. Eugene O'Neil (left in the photograph) has been awarded the 1971 IEEE
Award in International Communications.
Among the outstanding contributions to
the communications field for which he was
cited are technologies developed for the
first operational Telstar communications
satellite and transoceanic cable.
(continued on page 12)

Our town

The sun never sets in our town, nor do our microphones and sound systems
get any rest. "Our town" is the mecca for sound specialists, and here, Shure
Microphones and Vocal Master Sound Systems handle it all: you'll hear
them in hotel show rooms and lounges used by famous professional entertainers whose livelihoods depend on sound excellence; you'll hear them in
hotel convention halls, in club after club, in casino after casino; and you'll
hear them 'round- the-clock as keno scores are announced. Why? Because
the predictability and reliability of Shure microphones and sound systems
simply make everyone's job a lot easier. The Shure sound is the Las Vegas
sound
and we're proud of it.

Shure Brothers Inc.,

222 Hartirey Ave., Evanston, III. 60204.
Circle 4 on reader service card

www.americanradiohistory.com

NOVEMBER 1972

I-11

L.; 1=1 fl=

RADIO -ELECTRONICS

firsts

make learning
Electronics at home
fast and fascinating
give you priceless
confidence.
Some NRI

fit'sts in training equipment

IIlS

to give solid state 25" color TV, 5" wide

band oscilloscope, color bar generator and other

professional equipment engineered specifically for

educat;on. You work directly on the receiver as you
build it, discovering the practical aspects of TV servicing as you create a handsome new color console.
Only NRI includes an attractive woodgrain cabinet
without extra charge.
8

RADIO -ELECTRONICS

fi.ost, to give you a unique, exciting digital

computer with memory built especially for home training. You learn organization, trouble shooting, operation, programming as you build and use it. Performs
the same functions ascommercial computers. Lessons
stress computer repair. You conduct a hundred experiments, build hundreds of circuits. A solid -state
VTVM is included among ten training kits.

NOVEMBER 1972

www.americanradiohistory.com

NRI's "discovery" method is the result of over

half a century of leadership simplifying
and dramatizing training at home
The FIRSTS described below are typical of NRI's half century of leadership in Electronics home
training. When you enroll as an NRI student, you can be sure of gaining the in- demand technical
knowledge and the priceless confidence of "hands -on" experience sought by employers in
Communications, Television -Radio Servicing and Industrial and Military Electronics. Everything about
NRI training is designed for your education ... from the much -copied, educator -acclaimed
Achievement Kit sent the day you enroll, to "bite- size" well -illustrated, easy to read texts programmed
with designed- for -learning training equipment.

YOU GET YOUR FCC LICENSE OR YOUR MONEY BACK

There is no end of opportunity for the trained man in Electronics. You can earn $6 or more an hour in
spare time, have a business of your own or qualify quickly for career positions in business, industry,
government. And if you enroll for any of five NRI courses in Communications, NRI prepares you
for your FCC License exams. You must pass or NRI refunds your tuition in full. No school offers a
more liberal money -back agreement. The full story about NRI leadership in Electronics training is in
the new NRI Catalog. Mail postage -free card today. No salesman is going to call.
NATIONAL RADIO INSTITUTE, Washington, D.C. 20016 (In Canada write: NR! Rep ..,ao Progress Ave,, Scat borough. (,,

APPROVED UNDER NEW GI BILL

If you have served since January 31, 1955,

or are in service, check GI line on postage-free card.

designed from chassis up for your education

I'i1sI:

to give you true -to -life experiences as a

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you take in NRI Communications training, including
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operation and troubleshooting become a matter of
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fiist

to give you completely specialized

training kits engineered for business, industrial and
military Electronics. Shown above is your own training center in solid state motor control and analog
computer servo -mechanisms. Telemetering circuits,
solid -state multi- vibrators, and problem -solving
digital computer circuits are also included in your
course.
NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

11

You don't have

to get a college
in electronics
Next to a willingness to
work, nothing will improve your
chances of success in electronics
more than a college -level
education. But family obligations
and the demands of your job
may make it very difficult for
you to attend classes. That
doesn't mean you have to forget
about getting ahead. CREI
makes it possible for you to get
the college-level education you
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school.

Learn at home

get the advanced, specialized

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pay. All CREI training material
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engineers and scientists from
private industry and
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of these men is an expert in his

now, CREI students are

getting the latest

information on cable TV,

LSI chips, microminiaturization, lasers and
masers, telemetry
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electronics,
field of electronics. He knows
CREI -and you
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from your CREI study can be
applied on the job.

At your own pace, your

own schedule ... without giving
up your present job. CREI
lessons are written to be clearly
You can have confidence
understood without the presence
in CREI
of a teacher. Your problems are
Since 1927, CREI has
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helped tens of thousands of men
will work with you in a very
move ahead in every phase of
personal manner and give you
the electronics industry. You'll
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find CREI graduates and
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students in key jobs wherever
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readily through home study
up -to -date knowledge of
with
complete information
than they ever did in the
electronics is demanded.
on CREI programs
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Leading companies recognize
Not for beginners
Use postpaid cardthe quality of CREI education.
no stamp needed. If card
CREI programs are written Many pay all or part of CREI
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write: CREI, Dept. E 1411C,
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CREI education is
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continually being revised. New
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"

18

RADIO -ELECTRONICS

NOVEMBER 1972

to go to college
-level education
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44,

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urea

CREI, A Division of the McGraw -Hill

Continuing Education Company
Dept. E 1411C, 3939 Wisconsin Ave, N.W.,

Washington, D.C. 20016

Please send me free book with full information about
CREI Programs.
Name

Address
City
Employed by
Type of Present Work
I am interested in:

Age

State

Zip

Computers DElectronic Engineering

Technology ONuclear EngineeringTechnology
Industrial Electronics DElectronics Systems
Engineering OTelevision Engineering Non -Technical
Course in Computer Programming New! Cable TV
APPROVED FOR TRAINING UNDER NEW GI BILL

NOVEMBER 1972

www.americanradiohistory.com

RADIO- ELECTRONICS

21

LETTERS

(continued from page 16)

"discrete" RCA -JVC record

in practical
playback situations. In SQ, the Lf and Rf
signals are totally separated throughout
the encode-decode process, while in the
RCA -JVC, demodulation of the ultrasonic
carriers followed by dematrixing must take
place to separate Lf and Rf signals for 4channel listening.
PETER SCHEIBER

New York, N.Y.

A "BETTER" IC OP -AMP
Referring to the article "Op-Amps At
Work Using The 709" by B. R. Rogen in
Radio -Electronics, September 1972.
It would be a disservice to your readers not to mention the "741" second generation op -amp (RCA, CA3741, Motorola
MC1741). The 741 is a direct replacement
for the 709 and requires no external frequency compensation, is output short circuit proof. It is also "latch -up" free and
has a maximum of 30 volts (with a power
supply voltage of 15 vdc) differential input signal range.

ii"

o/

p
1U
p
'. ,.1 0
I

6111l0l,,llhh

New Orleans, La.

R -E

Ili

II

JAMES GUILBEAU

......IwllWlicu

i=i-i=i=i=i=i=i=i=rrrrri-rai-ri:rri=i=ri=r--ri-ri= -rri_i-i:

Give them the picture

they paid for with RCA
antennas and rotators.
combination for great reception -and great sales. Because you cover
all reception requirements...UHF, VHF /FM or UHF -VHF combinations...color or
black- and -white...metropolitan or fringe areas...with the full line of RCA Permacolor
antennas and RCA rotators. Each Permacolor antenna is precision engineered,
easy -to- install -a top quality performer. Every RCA rotator features dynamic turning
power and pin -point accuracy. Plus handsome styling for maximum customer appeal.
And RCA antennas and rotators were developed with the space age techniques and
thorough testing that have made the RCA name famous.
A great

So give your customers the picture they paid for with the name
they can rely on... RCA. The extra feature that means more
sales for you. At your RCA Parts and Accessories distributor.
Parts and Accessories, Deptford, New Jersey 08096

Circle 10 on reader service card

22

RADIO -ELECTRONICS

NOVEMBER 1972

www.americanradiohistory.com

The elderly person

in

nursing home. The woman

who must spend Christmas
a

hospital,
away from her family.
in the

The serviceman
far from home
on Christmas Day.

All get a touch

of holiday happiness
from The Salvation Army.
Your gift
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stereo
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=

SHORTWAVE
LISTENING

LLD

8 Sams Books to
update and broaden your
Electronics Skills
Three are newly revised editions ... 5 are brand new this fall
all will be valuable additions to your library.
ABC'S

OF

FM MULTIPLEXING FOR STEREO

NORTH AMERICAN RADIO -TV STATION

LASERS AND MASERS

(3rd Edition)

(8th Edition)

(3rd Edition)

GUIDE

By Allan Lytel and Lawrence Buckmaster

The completely updated explanation and review of the development and applications of
lasers and masers in measurements, communications, medical surgery, and industrial us-

by Vane A. Jones
Lists nearly 10,000 a -m, fm and television stations In the U.S., Canada, Mexico, and the
West Indies. Includes: power (day and night),
antenna height, and time sharing. Arranged by
geographical location, frequency (or channel),
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$3.50

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ABC'S OF INDUSTRIAL ELECTRONICS

(NEW)
By J. A. Wilson
Covers the circuits and applications of electronics used in manufacturing, together with
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shows how electronics have improved on old time methods of machine and process controls. 96 pages; 51/2" x 81/2 "; softbound.
No. 21)913
$3.95

LISTENING
(NEW)
By Len Buckw3lter
A valuable soy rce of information for both hob-

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antennas and installation, receiver improvements, accessories, Interference sources, troubleshooting tips, listening techniques. 144
pages; 51/2" x 81/2 "; softbound.
$3.95

No. 20911

101 QUESTIO+IS AND ANSWERS ABOUT

AM, FM, & SSB (NEW)
By Leo G. Sands
Easy -to- understand information about the three
basic modulation techniques and the various
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technical aspects and limitations of each in a
Q &A format. 96 pages; 51/2" x 81/2 "; softbound.
No. 20919
$3.95
1

-2 -3 -4 SERVICING

STEREO AMPS

(NEW)
By Forest H. Belt
Details the "divide and conquer" method of
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for best results. Many illustrations and schematics in this clear, easy-to -read manual. 240
pages; 51/2" x 81/2 "; softbound.
$4.95
No. 20912

$3.95

No. 20915

99 WAYS TO IMPROVE YOUR SHORTWAVE

...

By Leonard Feldman
Analyzes the fm stereo signal; gives requirements for fm stereo receiver; covers multi-

plex decoder circuit variety and servicing,

stereo indicator lights and automatic stereo
switching; test equipment and alfgnment procedures. 176 pages; 51/2" x 81h "; softbound.
$4.95

No. 20910

MARINE SINGLE SIDEBAND

(NEW, NOT SHOWN)
By Donald M. Stoner and Pierre B. Coral
Fills a void in published literature on the subject of Marine Single Sideband, the method
by which all marine electronic voice communications must soon be carried out. Covers
all facets of Single Sideband in marine communications. 192 pages; 51/2" a 31/2"; softbound.
$5.95
No. 24029

r
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HOWARD W. SAMS & CO., INC.

4300 West 62nd Street, Indianapolis, Indiana 46268

Order from your Electronics Parts Distributor,

or mail to Howard W. Sams 8 Co., Inc.
enclosed.
Send books checked at right. $
Please include sales tax where applicable.
Canadian prices slightly higher.
Send Free 1972 Sams Book Catalog.

20863

20915

20911

20913

20919

20910

20912

24029

Name

Address
Cy

State

71
RE112

Circle

II

on reader service card

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

23

USE IT ALL AT HOME AS YOU GET READY FOR A NEW CAREER!

$1,500.00

01'rth Of twoway
worth

radio electronic
communications
equipment!
Bell & Howell Schools announces a new learn -at -home
program that gives you "hands on" experience with
commercial-grade equipment as you prepare for
a business of your own in two -way radio electronic
communications servicing.
You need "hands on" experience with a real,
commercial -band FM transceiver and actual
commercial -grade test equipment -to take full
advantage of growing opportunities in electronic

communications.
Two -way radio communications is a healthy
growth area in electronics. And it's lucrative. Almost
two million commercial two -way radio systems now
serve as vital communications links for trucks,
planes, boats and taxis. And the FCC requires each
system to have its equipment serviced regularly
by a licensed technician. That's where you come in.
But you need career -oriented training -plus your
FCC license.

24

RADIO -ELECTRONICS

Knowing how to put an amateur radio kit

together won't help when you're "on the job" servicing two-way radio systems for aircraft or
advising trucking companies about their land- mobile
communications system. For that, you need "hands
on" experience with the real thing. This unique new
Bell & Howell Schools learn -at -home program
gives you just that. You can work with the equipment
by attending one of our special "help sessions" or by
dropping by one of the Bell & Howell resident schools.
If neither of these plans is convenient, you can have
the equipment shipped to your home in return for
a deposit, which is refundable when you
return the equipment.
Find out more about this exciting new Bell
& Howell Schools program. There's no obligation.

For free facts,

cut out and mail coupon today!

NOVEMBER 1972

www.americanradiohistory.com

Let Bell & Howell

Schools help you get
ready for an exciting
career or business
of your own
in two-way radio
electronic
communications!

Deviation Meter...
model favored by many
working technicians to
check modulation of

transmitted signal.

Frequency Meter ...

highly sensitive instrument used to check
signal frequency within
precise tolerances established by government standards.
Power Output Meter ... meter
used almost universally by trained
and licensed technicians to check
power output -or wattage of signal.
Alignment Generator... a
custom -designed unit you use
to gene.rate test signals for
transceiver alignment.

Bell & Howell Schools has helped many

thousands of people prepare for careers
and businesses of their own -in
electronics. You can have absolute
confidence in the training you get.
Expert instructors at Bell & Howell
Schools plan each program to answer a
single question: "What qualifications
will you need to take advantage of actual
career opportunities in electronics ?"
They then build each program to give
you those exact qualifications.
'lb get ready for a business of your
own in two-way radio, you need: 1) career oriented training; 2) FCC License; 3)
"hands on" experience with commercial grade equipment. Bell & Howell Schools
now offers this new at-home training
program that gives you all three. (See
FCC License Guarantee below.)

Just look at all the equipment

you'll work with -right at home

- during your training program
with Bell & Howell Schools!
Commercial -Band FM Transceiver

...exactly the kind of two -way radio

you'll service throughout your career.

FCC regulations give you the

opportunity to start your own

business!
The Federal Communications Commission requires that all commercial
two -way communications systems be
checked and serviced by a licensed
technician at regular intervals.
As a Bell & Howell Schools graduate,
you'll have the technical know -how you
need. With your FCC license, you can
go out and eventually build your
own business signing contracts with
companies that use two-way radio.
FCC regulations could mean security
and regular income for you!

Bell & Howell Schools offers you

these special advantages:

Help Sessions Scheduled regularly
every few Saturdays at the Bell & Howell
Schools and in many other cities
throughout the U.S. and Canada. Top
instructors give you personal help
and guidance.
Transfer Privileges After completion, you can transfer to any of the
resident schools for more advanced

study, if you wish.

Lifetime National Placement Assistance Helps you locate a job where you
want to anytime after you complete
program.
Veterans' Benefits We are approved
by the state approval agency for
Veterans' Benefits.
Student Financial Aid We are
an eligible institution under the Federally
Insured Student Loan Program.

Exclusive Electro -Lab

yours to keep!

To make sure you get practical

experience with instruments used daily
by professionals, we've integrated into
your program three precision instrument
kits you assemble yourself and keep!
Design Console Use this to
rapidly "breadboard" circuits without
soldering.
Oscilloscope Offers bright, sharp
screen images, 3 -way jacks for leads,
plugs.
Transistorized Meter Registers
current, voltage and resistance.

Guarantee
Obtaining

a commercial radio -telephone license from

the FCC is necessary for many jobs in two -way and
broadcast communications. Bell & Howell Schools
guarantees that if after the successful completion of
this course, including a supervised final exam, you
take and fail to pass the First Class license exam, we
will offer at no additional charge the tutoring
necessary to enable you to pass the exam. This help
may take the form of special lessons at home,
attendance at a Help Session, or special assistance
at one of our resident schools (in this case you would
be responsible only for travel and living expenses).
If you accept the help, then take the exam and are still
unable to pass the First Class license, a complete
refund will be made of all tuition paid. This guarantee
is good only if the student first takes the exam within
six months of completing the course and takes a
re -exam within six months of completing the review
course. If he fails, he must advise Bell & Howell
Schools within 30 days of receiving his notice of failure
and follow the tutoring program suggested by
the school.

For free information, mail coupon today! or write:

DrVRV IOSTITUTE OF TECHOOLOGV
ONE OF THE

BELL E HOWELL SCHOOLS

4141 Belmont Avenue, Chicago, Illinois 60641

41)3

Bell & Howell Schools, 4141 Belmont Avenue, Chicago, Illinois 60641

OKAY...

Please send me free information about the $1,500.00

worth of two -way radio electronic communications
equipment I use in my own home as I prepare for a
new career in two -way radio.
NAME

please print)

ADDRESS

CITY

STATE

TELEPHONE

Check here for information about:

ZIP
AGE

Veterans' Benefits

Student Financial Aid

MD2N

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

25

DISTORTION -TEST
AUDIO EQUIPMENT

easily

quickly
accurately

equipment

report

Heathkit 10 -105
triggered -sweep
dual -trace scope

Now the TECRON IMA makes

measuring IM distortion even
easier than measuring THD!

nate mode, the two signals are displayed alternately on successive sweeps.
Of course, as the sweep speed is increased, the two signal traces seem to
appear simultaneously. In the chopped
mode, the two signals are sampled at a
rate of 50 kHz.
A third mode: X -Y, displays channel on the vertical (Y) axis and channel 2 on the horizontal (X) axis. This
mode is useful when making input -out1

Just one piece of equipment has

both internal oscillators and inter modulation distortion analyzer. Simply
connect the oscillator output to the
input of the test unit, and hook the
unit's output to the input of the analyzer. One quick set up, then switch
single control to simultaneously
a
adjust input and output levels. Take
up to ten power level measurements
in 5db steps in just 60 seconds! Readings over a wide span of output levels
fully describe the distortion characteristics of the test unit.
The IMA itself has a guaranteed
residual IMD of less than 0.005%
(typically under 0.003 %). There are
seven IM ranges with accuracy assured to within 5% of full scale ( +0.005%
on the 0.1 full scale range).
As all other TECRON laboratory
instruments, the IMA is of advanced
design, ruggedly constructed from
highest quality components by skilled

American craftsmen.
Product literature is free upon request. For a technical discussion on
the advantages of using IM testing to
detect audible distortion, send 25(C for
A.E.S. Preprint No. 871(B -9) to Crown

International, Box

1000,

Elkhart,

Indiana, 46514, U.S.A.

Full input and output metering; also full input
and output monitoring oscilloscope terminals

solid state construction, utilizing FETs for stability and compact size (7 "x 19 "x 7 ")
full
complement of level controls
two internal

oscillators eliminate the need for additional

test equipment
rack mount list price $570,
with walnut cabinet $595

Made Only in America

0 Tecron
26

Circle

11 on

put linearity comparisons, studying

Circle 100 on reader service card

OLDTIMERS WILL REMEMBER THAT ONE

of the first Heathkits marketed some

25

years ago was a low -priced oscilloscope.

The IO -105, Heath's latest, is a far cry
from that instrument. It is probably the
first oscilloscope kit to incorporate
many features found only in laboratory

instruments of considerably higher

price. Like its lower priced cousin the
I0-103 (Radio-Electronics, June, 1972),
it is an all solid -state triggered -sweep
instrument. However, as a study of its
specifications will show, it is a good deal
more sophisticated than the IO -103 and,
therefore, can be used in many more
applications, either in design work or on
the service bench.
The dual -trace feature is a tremendous advantage in many kinds of design
or service work since it permits the user
to display two separate input signals
side by side for direct comparison. Or
one of the channels can be used to display an input signal while the other is
displaying the same signal after it has
passed through the piece of equipment
being tested. A common time base is
used for both the channel 1 and channel
2 amplifiers. When displaying two channels simultaneously, the user has a
choice of two different modes of operations: alternate or chopped. In the alter-

reader service card

RADIO -ELECTRONICS

phase shifts and for displaying Lissajous

patterns.
The channel and 2 amplifier circuits contain identical wide -band amplifiers with a response from dc to 15
MHz with a variation of 3 dB. The rise
time is 24 ns with an overshoot of less
than 10%.
Both channels have 9- position attenuators in a 1, 2, 5 sequence providing
a range from 50 mV /cm to 20 volts /cm.
In addition, each channel has an uncalibrated variable gain control which can
be used for vernier gain adjustments.
The input impedance of each amplifier
is 1 megohm shunted by 35 pF. Either
ac or dc coupling is switch selectable.

NOVEMBER 1972

www.americanradiohistory.com

Sweep circuits
The horizontal time base has 18
calibrated rates ranging from .2 s /cm
to 100 ms /cm in 1, 2, 5 sequence. Sweep
accuracy is 3 %. There is also a continuously variable uncalibrated sweep
speed control. In addition, a panel push
button provides a sweep magnification

of

times.
The calibrated time base makes it
possible to measure the frequency of
any input signal within the frequency or
voltage ranges of the instrument. This is
one of the great advantages of a triggered sweep scope with a calibrated
time base. Charts are provided in the
instruction book for converting the
TtME /cM selector switch settings to frequency. And the triggered sweep, of
course, makes it easy to lock into a signal of any frequency for measurement
or observation. Four triggering switches
give great flexibility. The first selects either external, line or internal triggering;
the second provides for ac or dc triggering. The third is for triggering either on
5

(continued on page 87)

RE E

son
IN 'YOUR

UFE

ELECTRONICS
FOR THE

send today for the all-new

'son

1973 CATALOG
NOW the only catalog offering
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YOUR COMPLETE BUYING GUIDE
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catalogs to:

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of everything
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City
State

Olson Electronics
where the values are!
Circle

13 on reader service

Zip

-J

card

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

27

From Cleveland Institute of Electronics

learn by doing!
Perform more than 200 exciting experiments
with CIE's fascinating ELECTRONICS
LABORATORY PROGRAM!

28

RADIO -ELECTRONICS

NOVEMBER 1972

www.americanradiohistory.com

You get your own 161 -piece electronics laboratory...

with authentic electronic components used by industry!

You learn how to construct circuits and

connect them with a soldering iron, which
is part of your CIE laboratory equipment.
This "hands on" experience is extremely
valuable in applying what you learn.

Testing and troubleshooting are an important part of your learning experience.

Included in your laboratory is a precision
"multimeter" to diagnose electrical and
electronic troubles quickly and accurately.

Modern space -age components like this

IC (integrated circuit) are professional
quality and can be used again and again
in many of your projects. Lesson by lesson,
piece by piece your knowledge grows!

Prepare now for a high income career in Electronics...the Science of the Seventies.
Electronic miracles are changing
today's world with breathtaking
speed.
And with this growth in electronics
a brand new
need ... a demand for thousands of
electronics technicians, trained in
theory and practice to build the
products, operate them and service
them during the Seventies.
Don't just wait for something to
"happen" in your present job. Get
ready now for a career you'll really
enjoy with a good income and plenty
of opportunity for advancement.

technology has come

Experience with experiments

is your best teacher
"Hands on" experience helps to reinforce basic theory. When you
learn by doing, you discover the
"how" as well as the "why." You'll
find out for yourself the right way as
well as the wrong way to use electronic components. How to construct
your own circuits, to discover trouble
spots and learn how to fix them. And
with CIE's special Auto -Programmed
Lessons, you learn faster and easier
than you'd believe possible.
CIE's fascinating course, Electronics Technology with Laboratory,
teaches you Electronics by making
it work before your eyes. And you do
it yourself, with your own hands.

Importance of FCC License

and our Money -Back Warranty
Many important jobs require an FCC
License and you must pass a Government licensing exam to get one.
But, a recent survey of 787 CIE
graduates reveals that better than 9
out of 10 CIE grads passed the FCC
License exam.
That's why we can offer this famous Money -Back Warranty: when

you complete our Laboratory Course,

which provides FCC License prep aration, you'll be able to pass your
FCC exam or be entitled to a full
refund of all tuition paid. This war -

ranty is valid during the completion

time allowed for your course.
You get your FCC License
or
your money back!

You'll have high paying

job opportunities
Electronics is still young and growing.
In nearly every one of the new exciting fields of the Seventies you find
electronics skills and knowledge are
in demand. Computers and data processing. Air traffic control. Medical
technology. Pollution control. Broadcasting and communications. With a
CIE Diploma and an FCC License
you can choose the career field you
want ... work for a big corporation, a
small company or even go into business for yourself.
Here's how two outstanding CIE
students carved out new careers:
After his CIE training, Edward J.
Dulaney, President of D & A Manu-

Approved
under
G.I. Bill
All CIE career
courses are ap-

CIE
I

Send now for 2 FREE BOOKS

Mail the reply card or coupon for our
school catalog plus a special book
on how to get your FCC License. For
your convenience, we will try to have
a representative call. If coupon is
missing, write: Cleveland Institute of
Electronics, Inc., 1776 E. 17th St.,
Cleveland, Ohio 44114. Do it now!

Cleveland Institute of Electronics, Inc.

1776 East 17th Street. Cleveland. Ohio 44114
Accredited Member National Home Study Council

in:
Electronics Technology with Laboratory
Industrial Electronics
Electronics Technology
Electronic Communications
First Class FCC License
Broadcast Engineering
Electronics Engineering

am especially interested

benefits

under the G. I. Bill.

If you are a Veteran
or in service now,
check box for G.I.
Bill information.

Please send me your two FREE books:

1. Your illustrated school catalog, "Succeed in Electronics."
2. Your book, "How to Get a Commercial FCC License."

proved for educa-

tional

facturing, Inc., Scottsbluff, Nebraska,

moved from TV repairman to lab
technician to radio station chief
engineer to manufacturer of electronic equipment with annual sales
of more than $500,000. Ed Dulaney
says, "While studying with CIE,
learned the electronics theories that
made my present business possible."
Marvin Hutchens, Woodbridge,
Virginia, says: "I was surprised at the
relevancy of the CIE course to actual
working conditions. I'm now servicing two -way radio systems in the
Greater Washington area. My earnings have increased $3,000. bought
feel
a new home for my family and
more financially secure than ever
before."

Name

Age
(PLEASE PRINT)

Address
City

Zip

State

Veterans and Serviceman: Check here for G.I. Bill information.

RE-10

Circle 14 on reader service card

NOVEMBER 1972

www.americanradiohistory.com

RADIO- ELECTRONICS

31

Our 39 audio power transistors replace...

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and thousands more.

There are a lot of identical transistors around hiding under different
manufacturers' part numbers.
But we've boiled power transistors
down to just 39 types that will handle
almost all of your replacement problems.
And we've also put together a cross reference guide that tells you which
one replaces which.
Our cross -reference guide also tells
you about the rest of our ECG replacement semiconductor line. Altogether
they car substitute for 53,000 others.

Practically everything from diodes

to integrated circuits.
And we don't stop there.
The ECG semiconductor line includes a variety of heat sinks, heat sink compounds, transistor mounting
kits, and sockets.
In short, carrying Sylvania's ECG
replacement semiconductor line can
take a big load off your back.
And you can still give power to the
people.
Sylvania Electronic Components,
Waltham, Mass. 02154.

03,3 SYLVANIA
www.americanradiohistory.com

cover story/cover story/ cover story/ cover story

The foundation or mainframe of a group of useful

and inexpensive digital test instruments

for the lab, service shop and experimenters' workbench. Accessories plug into the readout.

BUILD R -E's
GRINCHWAL DIGITAL
TEST EQUIPMENT
VIRTUALLY EVERY DIGITAL INSTRUMENT

needs an accurate internal time or frequency reference. For instance, an electronic digital counter needs 0.1 -, 1 -, and
10- second time gates, while an electronic stopwatch may need a source of
10- microsecond wide time period
pulses, or a digital voltmeter may need
a stable source of 100-kHz timing signals for dual -slope integration, used for
accurate voltage to frequency conversion. This internal reference is usually called a time base.
One cheap time base is the power
line, but it's hard to use in a batterypowered instrument and it doesn't have
enough accuracy or stability to do justice to 4 decades of counting. So, traditionally, you had to go to a crystal oscillator and a bunch of current- hogging
RTL or TTL decade dividers.
The digital grinchwal* does things
differently. It starts with a crystal all
right, but it uses a single integrated circuit that will give you any time or frequency reference you ask it to, from 1
MHz to
pulse per hour! To make
things even nicer, the integrated circuit
only draws 5 mA.
Figure 1 is a block diagram of the
1

`grinchwal, n, (originated by author): gizmo, gadget,

thingamajig. The digital readout and timebase of a multipurpose test instrument featuring plug -in modules for various functions or operations.

Mostek MK5009 time -base integrated

circuit. You hang a 1 -MHz crystal and
some biasing and trimming components
on its internal oscillator. You then send
it a four -line code command that tells it
how much to divide by, and out comes a
reference frequency or time period that
talks to the grinchwal counter or that
can drive an ordinary RTL, DTL, or
TTL integrated circuit. To program the
IC to a desired division ratio, you use
the code of Table 1. There are four input lines, called A, B, C, and D. A digital "0" is equal to ground, while a digital "1" is at or near the +6 -volt supply.
For instance, if you start with a I -MHz
crystal, and apply the code 0101, or
A = 1, B = 0, C = 1 and D = 0, the IC
divides by five decades, or 105, giving
you either a 10 -hertz output signal or a
100-millisecond period square wave.
Accuracy to four decades can be obtained by trimming the crystal against
WWV or another frequency reference,
but even without any trimming you get
a very stable and very accurate output.
You also get a reset input. Ground it
and the IC runs normally. Make it 6
volts positive and the chip puts all its
dividers in the 0 state. This is handy to
gate your reference frequency for things
like electronic stopwatches and sports
timers. The reset and counters are syn-

by DON LANCASTER

chronous. This means the first output

cycle will be within a millionth of a second of the width of all the rest of the cycles.

There are several precautions in using this chip. Never apply reverse supply voltage or you will instantly zap it.
Also, the unused inputs must be connected exactly as shown in Fig. 2, for
the IC has some internal -test speedup
modes it can get into if you, say, try to
use -12 volts instead of ground for a
logic "0 ". Note the 1 -MHz direct output
is too fast for the MK5005 counter and
display plug-in, and thus can only be
used on external circuits. With the addition of resistor RI, the two chips can
talk to each other at any other reference
time or frequency. And, like any other
MOS device, an exceptionally unreasonable amount of mishandling can
damage the chip, so leave it in its conductive foam carrier until after you
have checked all the rest of your circuit
out; then quickly and carefully solder it
in place with a small soldering IRON
(No guns please) and fine solder.

Building the mainframe

The schematic is in Fig. 2. Circuit
boards, complete kits, and any and all
parts are available from the source
shown in the parts list. The grinchwal is

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

33

built in an unbreakable impact plastic

case 5 x 61 X 21 inches deep. The
power supply or the batteries mount in
the upper bottom of the case, underneath a main PC board that contains
the timebase and connector for the
plug -ins and the counter module. A
front panel covers the top half of the
case, supporting a red filter for the display module, the CHECK and RESET
pushbuttons and the OVERFLOW indicator. Besides the timebase and connectors, the PC board contains some
supply filtering and reverse- polarity
protection, a pulser for the reset line, a
driver for the overflow indicator, and a
"relay" (Q2, Q3) to control the -12 -volt
supply.
The PC board is shown in Fig. 3.
You can get this commercially or etch
and drill your own, using this pattern.
All the components except IC I may be
mounted in place, watching the polarity
on all the capacitors and diodes. A
small four -wire flat cable makes the
front panel connections neater, but
plain old wire can be used. Note that
the overflow indicator, being a light
emitting diode is polarity sensitive. Be
sure to connect it exactly as shown in
the schematic with the narrow pin going
to the IND terminal and the wide pin going to ground. Don't add IC 1 till after
the preliminary checkout.
You have a choice of batteries or a
line -operated power supply. The battery
supply -for maximum portability -consists of two 9 -volt transistor radio batteries and four type C cells (alkaline for
long life) connected as in Fig. 4-a. Note
that the +terminal of the 18 -volt battery goes to the +terminal of the 6 -volt
battery, not to ground! Use the line -operated supply in Fig. 4-b if you don't
really need extreme portability and like
to leave test instruments on for long periods of time. If you want to use both
a power supply and larger batteries or
rechargable batteries, you'll probably
want to go to a somewhat larger case. A
two -transistor and transformer inverter
may be used to convert the +6 volts to
-12 volts if you want to do away with
the two 9-volt batteries.
Whatever route you pick, the
power source mounts under the main
PC board, leaving the bottom half of
the case open for the plug -ins. Power
needs are 6 volts at 125 mA and -12 at 5

Q2, Q3 relay it also controls -12 volts.

The decimal -point selector goes be-

tween
DP 100,

will follow the counting if grounded

and keep the old count if at +6 volts.
Reset for the count module forces the
counter to zero if it is grounded. If you
push the RESET button, you get a brief
pulse going to ground on this terminal

DP IN and the chosen DP 1, DP 10,

or DP IK. If you don't connect it

or else connect it to DP I, you'll get just a

number displayed with all three left hand zeros lopped off. If you can arrange things so you get a "0" reading
between measurements, this will radically extend the battery life.
The timebase is activated by
switching a "1" ( +6 volts) and a "0"
(ground) to inputs A, B, C, and D following the truth table of Table I. The
timebase OUT terminal may be connected directly to the COUNT terminal of
the counter /display, or else it will drive
one TTL or DTL input. You reset the
timebase by putting +6 volts on the
normally grounded RST line.
The COUNT input may be connected to a RTL, DTL, or TTL output
in your plug -in, to the timebase output,
or to + 5 volts through a capacitor. It
free runs (self-oscillates) with the capacitor and follows the counting with
either the timebase or your external
low- impedance logic source. UPDATE

every time you hit the button. You can

use this for a resetting signal for your
plug in. Note that the resets of the
counter and timebase are backwards in
action. If you decide to reset both at
once, you need an inverter to ground
the counter while applying +6 volts to
the timebase. RESET only resets the
counter, not the display. To get a 0000
reading, you have to simultaneously reset and update the counter module.
The OVERFLOW output goes to
ground on count 10,000 and stays there
until reset. It may be directly connected
to the IND input to light the overflow
lamp, or it will drive one logic load in
your plug -in. If you want to independently light the overflow indicator, you
ground the IND input instead of connecting it to the OVERFLOW output on
the counter module. A ground lights the
lamp; +6 volts puts it out.

-12V

1N5288
CONSTANT
CURRENT
DIODE

+6v
o

OSC TEST
O
10

SCHMITT
TRIGGER

1.0

MHz04

OUTPUT

1.0
NM MHz

lo
MEG

10K

XTAL

100 KHZO
+6V

:10

6.8 MEG

+6v

10 KHZ

TIME SELECTOR

3301,

Lai

10

3.3 MEG
10

10

KHZO

100 Hz

MK5009

10 Hz

16

o
-12V

---10-?

5 mA

=10

10

Hz

10 SECO

100 SEC

mA.
1

Using the mainframe

We'll be showing you several plug ins from time to time, but if you're designing your own modules, the following guidelines should be of some help.
The power ON-OFF switch goes between +6 volts and +6SW. With the

+6V

ALL STAGES

COUNTING
STATE 0

COMMAND
DECODER

}
111112j13j14

CONNECT TO +6V OR
GROUND PER DESIRED
TIME

struments.

RADIO- ELECTRONICS

MINA

1HOUR0
RESET
INPUT

FIG. 1 -BLOCK DIAGRAM of the time -base IC

and the basic circuitry. This and the digital
readout form the heart of several test In-

34

BUFFER

NOVEMBER 1972

www.americanradiohistory.com

TIME SELECT
LINES

PARTS LIST

-3 -30 pF trimmer capacitor

C2 -5 pF mica capacitor -optional;
C1

needed only

with certain cyrstals

C3, C5, C7 -0.1

10 -volts

IMF,

disc ceramic capaci-

tor
C4 -47 F, 15 -volt electrolytic
C6- 220 F, 6-volt electrolytic
D1, D2 -1N914 diode

D3-D6-1N4001 diode
D7- 1N5288 constant -current diode DO NOT
SUBSTITUTE
IC1- MK5009P time base IC (Mostek), special
design built for Don Lancaster projects.
LM1- MV5023 LED panel lamp or equivalent
S1,2 -Spst momentary pushbutton
Q1,2- 2N5139 transistor, silicon pmp
Q3- 2N5129 transistor, silicon npn
R1,6,8 -10K, Y watt carbon resistor
R2-2.2 megohm carbon resistor
R3-6.8 megohm, carbon resistor
R4 -3.3 megohm carbon resistor
R5-1 megohm carbon resistor
R7 -330 ohm carbon resistor

MISC: PC Board per Fig. 3, plastic case; 9-volt

battery clips (2); spacer foam for batteries; Dual C holders (2); front panel;
red filter; mounting hardware, wire; solder.

POWER SUPPLY PARTS LIST

C1- 5000

F, 10 V

electrolytic

C2, 3- 500 F, 25 V electrolytic

D1, D2, D3, D4- 1N5061 silicon power diode, I
A to plv
D5-12 -V Zener diode, 1N4742 or equivalent
F1 -0.1 A fuse and fuseholder
ICI
-V positive regulator, Fairchild 7806

NOTE: The following are available from Southwest Technical Products, 219 West
Rhapsody, San Antonio, Texas, 78216:
PC Board, etched and drilled No. DGMb, $4.85 postpaid. Circuit board for
readouts, No. DGR -b, $3.85 postpaid.
Kit of parts for readout, No. DR -C,
$34.50. Kit of parts for mainframe and
timebase plug -in, including case and
front panel, No. DM -C, $26.75, less

-6

R1
T1

-27

ohms,

-12,6 VCt,

12 -100

watt

'

100 mA transformer (Signal PC

or equal)

MISC: PC Board for power supply, line cord; PC

terminals (Optional) (5); solder.

readouts and batteries, postpaid.

"OVERFLOW"

"CHECK"

RESET
OLM1

MV5023

S2

R9 -4.7K, carbon resistor

S01-4-10-pin chassis mounting socket, Molex

09 -52 -3103

XTAL

-1.00

IND

RESET

GND

TEST

FRONT PANEL MOUNT

MHz crystal and mounting clip

C3 0.1

R7

330
Q1

R5

2N5I39
DP1K O
DP100 O
DP10 O
O
DP1
NC
O
+6
0
NC
NC

DPIN
GND

R6

R8
10K

D1u

Cl

XTAL

C2

3-30 pF

IN914

1.0 MHz

O
S01

R4

R3

10 MEG

6.8 MEG

TO COUNT
D7

MODULE

DO NOT

3.3 MEG

OSC

SUBSTITUTE

-O

R2

IN5288

02
NCO NC
O UPDATE
O RESET
COUNT
NCO EXTEND
OVERFLOW
O GROUND
O BLANK

111

5 pF

MEG

10K

NC O SCAN

TEST

-0 LAMP TEST
SO2

C7
0.1

ICI

TO COUNT
MODULE

MK5009
TOP VIEW

Q2

2N5I39

C6

220 pF

R9

RI

4.7K

C5

10K

+6V SW

-12V

Q3

C4
++47F

2N5I29
D6

D4

+6V BAT

-0

D3-D6

D3IN4001

D5

"8"

GROUND

oC4

O OVERFLOW
O COUNT
O RESET
O UPDATE

O TB OUT
O TB RST

DP IN

OB "2"
-0 A "1"
+6V
SW

GND

+6V
BAT

-12V

S03

POWER INPUTS

FROM BATTERY
OR LINE SUPPLY

OOF IND

-0

O DPIN
O 12V
O +6V BAT
0 +6V SW

DPIK
O DP100
O DP10
O DPI

TO PLUG -INS

SO4

FIG. 2 -THE SCHEMATIC shows details of the switching, power

control and oscillator circuits.

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

35

When you're using the grinchwal

with your plug -ins, there are two additional design quirks you have to allow
for that could cause you some headaches if you don't know about them.
First, note that resetting the counter
also resets the internal digit scanner. If
you reset the counter too often, some of
the numbers will not get displayed, or
some of the digits may vary cyclically in
brightness. To get around this, limit the
number of new measurements you
make to less than 30 per second. If you
must go faster, the scanning capacitor
(C 1) on the counter plug-in could be reduced in value, but too small a C
causes decimal -point ghosting and possible leading-edge blanking problems.
The second thing you have to allow
for is to make sure that at least one
count happens after you update if you
want to keep the old answer and not reset immediately. This means you can't
directly use the falling edge of an input
gate as an update if it does away with
the input at the same time. The input
signal should continue at least one
count after updating- making it nearly
continuous is one obvious way around
the problem.

FIG.

3- MAINFRAME

PC BOARD

pattern (above). Enlarge so

board is 5 inches wide across
the top. FIG. 4 (below) -POWER
SUPPLIES are optional. If you
use batteries as at (a), be sure
that connections are made as
shown. In the ac supply (b) the 6volt source has an IC voltage
regulator while the 12 -volt
source is controlled by a 12 -volt
Zener diode.

Ideas for plug -ins

Timebase -Bring out the timing
signals and you have a precision scope
calibrator, source of timing signals, precision digital clock pulses, a source of
timing clocks for lab experiments, an
ultra -stable squarewave generator, etc.
Stopwatch -Simply gate the time -

RED

next month

-6V BAT

SPACE LIMITATIONS prevent us

from presenting the remaining
printed- circuit diagrams and construction information in this issue. All remaining diagrams and
text will appear next month.

9V BAT

BLACK
GND

9V BAT

7806
TOP

IN['

-12V
BLK

T1

6 VOLT
REGULATOR

VIEW

YELLOW

['

IC1

['OUT

7806

GND

100 mA
D1

L
6.3V

^
+

OPTIONAL
-12V SUPPLY

'

CIRCUITS

D4

C2

500/25V

^
IN5061

R1

e-1/W27,0

C3

500/

125V

-12v

D5
12V

IN4742

36

lov

D2

D3

FOR OUTSIDE

RADIO -ELECTRONICS

GND

Ci
5000 pF

IN5061

+6v

OUT

IN

6 3V

base with a set -reset flip -flop to get the

time between events, or gate it directly
to get the duration of a single event.
You can measure any time interval
from 10 microseconds to 9999 hours.
Use it for a sports timer, a rally computer, photographic stopwatch for shutter testing, physics experiments, ballistic
velocity checks, etc .
Frequency counter -Use the 0.1 -, I, or 10-second output of the timebase to
turn on and off a signal whose frequency you want to measure. The input
frequency should be conditioned by going into a digital comparator. Maximum direct operation is around 200
kHz, but you can easily add scalers to
count any frequency you want. With
Schottky TTL, you can count beyond
100 Mhz, and by using more than one
trip through the counter, you can get
more than 4 decades of accuracy. For
instance, a 10- second gate and scalers
can give you a six -digit accuracy, for
any input above 100 khz.
This list could go on and on. What
can you do with a completely portable
instrument that will measure or monitor
anything you want to 0.01% accuracy?
We'll show you how to do some of the
common plug-ins. How about you
showing us newer and better uses for
R -E
the Grinchwal?

NOVEMBER 1972

www.americanradiohistory.com

1- SKETCH OF VOLKSWAGEN computer

system in operation.
FIG.

computer checks out your car

of things to come, Volkswagen's built in self- analysis system slashes auto diagnosis time.

A fore- runner

by FRED W. HOLDER
VOLKSWAGEN SCOOPED THE AUTO INDUSTRY IN 1968 WHEN IT

introduced electronic fuel injection to avoid the use of powerconsuming anti -smog devices. Another "first" is in the offing:
computerized self analysis, a system designed to revolutionize
automotive diagnosis. Volkswagen is introducing this new
system at U.S. dealerships now. The system has been in use at
European dealers for some time.
VW's Computerized Self- Analysis System is designed to
checkout 1972 and later model Volkswagens, that have a built
in central test socket and a network of sensors. It will, however, checkout any 12 -volt VW (1965 and later models)
through the use of an adapter cable. With a capability for 150
test operations, the system currently makes more than 60 separate checks on the VW Beetle in just 21 minutes. The current
diagnosis method takes approximately 42 minutes to complete. The customer receives a printout showing exactly what
work needs to be done to bring his car to standard specifications. With this check sheet as a guide, he may save on both
parts and shop time.
The system uses space -age telemetry techniques to perform complicated checks of front -wheel alignment, ignition
performance, engine compression, and battery condition in

just seconds. The technician connects the system's digital

computer to the car's sensor network with a single, multi strand cable which plugs into the car's central socket. He then
inserts a program card into the computer card reader to provide specifications on the year and model of VW being tested.
The program card is run through the computer as the technician signals the next test step with a hand-held input unit.
The system produces both visual and printed results as the
test progresses.
At certain points in the count-down, the system switches
to automatic sequence and performs a variety of checks in
rapid succession, comparing the readings against standard
values and printing the results on a high -speed printer. For
example, during one of the four automatic sequences, checks
are made and the results printed for: battery voltage, voltage
under load; parking, tail, and license plate lights; operation
of stop lights; battery acid level; turn signals left; turn signals
right; and rear window defogger.

System components
Figure shows the principal components of the system.
Item (1), and the insert, shows the central socket and the test
1

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

37

cable used to connect the car to the computer (2). The thin armored cable leading off the top of the plug reads engine oil
temperature. The computer console contains the program
card reader (3). Each VW from Beetle to Bus has its own program card. Results of the more than 60 checks performed on
the vehicle are recorded by the high -speed printer (4).
Many of the tests are performed by the technician using
a hand -held input unit (5). The technician is told the "count
down" sequence by a visual display in the hand -held unit.
Buttons are provided to indicate GO and NO -GO conditions for
visual checks.
Front wheel alignment is inspected using a photo -electric
unit (6). The condition of the alignment is tested and recorded simply by turning the steering wheel. At a given position, camber and toe -in are recorded for each front wheel.
Headlights are checked for both brightness and adjustment
by the tester (7) mounted on tracks at the front of the car.
Proper setting of the car for front wheel and headlight checks
is ensured by positioning it on four pads (8). These pads also
place the car correctly over a hoist that lifts the car for under vehicle inspections.

gated with the BCD digit at gate group G 1. At the start of the
conversion time (when the time base signal enables the gate
and allows the ADC signal to drive the BCD counter), the
counter data content is zero and the flip -flop FF 1 is in the NOGo state. As the count increases and reaches the lower limit, a
coincidence signal is generated by gate G2 and flip -flop FF1
is set to the GO state. If the BCD counter value exceeds the
upper limit at gate group G3 before the time base signal stops
the count, flip -flop FF 1 is reset to the No-Go state. The results

rr

MULTI LEX

rIONING

>

COMPARATOR

DtGITAL

CONVERTER

Functional description
As shown on the block diagram of Fig. 2, test signals
from the car's sensor network are routed through a 28- strand
cable to the signal conditioning circuits. Here, the signals are
conditioned, amplified, filtered, and brought into a system-

COMPUTER

MANUAL

CARD
READER

INPUT
UNIT

2 -BLOCK DIAGRAM of computerized sel -analysis system shows

the major functional areas and their interconnections.

FIG.

ANALOG TO

DIGITAL
CONVERTER

rBCD COUNTER

STAGE
L

TIME
BASE

STAGE

STAGE 3

J
G1

G2
LOWER LIMIT

R- -FG1

TECHNICIAN USES HAND -HELD INPUT UNIT to follow test countdown.

Unit feeds the test findings Into the computer at left.

compatible form. They are then available for multiplexing

and further processing.
Analog storage holds peak and temporary data until it is
called for by the multiplexer. The multiplexer uses field -effect
transistors and reed relays to select the desired test data channels, as instructed by the test step on the program card, and
routes it to the analog -to-digital converter (ADC). The ADC
converts the analog voltage signal to its equivalent as a three
digit binary coded decimal (BCD) number for display and
printing. The ADC is a voltage -to- frequency converter with a
conversion rate of 100 Hz per volt.
With an input voltage of 10 volts, the total error is less
than 0.5 %. The output frequency is gated with a time -base
signal and used to drive a three-digit BCD counter. The output of the counter is decoded and displayed. Also, the BCD
data value is simultaneously checked in the dynamic comparator to determine whether it is within 'the tolerance limits
specified by the program card.
Figure 3 shows the working principle for one BCD digit
of the comparator. The lower tolerance range limit digit is
38

RADIO -ELECTRONICS

GO

NO GO

G4

UPPER

LIMIT

um.
3- SIMPLIFIED DIAGRAM OF COMPUTER CIRCUIT used to check
test values from the automobile against specified limits.
FIG.

of the comparator check are displayed on the computer console and printed as a plus or minus sign next to the actual
data value. The printer is a version of the standard type used
in small calculators. It has been adapted to meet the special
application of this system.
Testing progresses automatically until a visual or manual
test must be made. (Such tests include operation of the windshield wiper, windshield washer, condition of tire tread, oil

NOVEMBER 1972

www.americanradiohistory.com

leaks, etc.) At this point, a film strip in the hand -held manual
input unit tells the technician what to check. If the item
checks OK, he presses the plus -sign button; if it doesn't, he
presses the minus -sign button. Either button advances the sequence to the next item to be checked. The technician continues to perform tests until another automatic sequence is
reached. The film then advances automatically in synchronization with the test program as checks are completed until
another manual check is indicated on the program card. This
procedure continues until all of the more than 60 tests are
completed.
All of these activities are supervised by the central control unit, which receives inputs from the program card, the
manual input unit, and the car itself. It generates the control
signals necessary to perform each test step and record the resulting data.
The program card has a capacity of 150 test steps although only about 60 are used at present. The card contains a
32 -bit control word for each test step as shown in Fig. 4. Bits I
through 6 designate the test subprogram to be used and bits 7
through 14 designate the multiplexer data channel to be sampled. Bits 15 through 22 contain the lower acceptable limit

0O0 00
6

DESIGNATES
TEST
PROGRAM

9 10

mm mm 20m
19

16

mance, compression, dwell angle, generator and regulator,

and headlights. All of these items except wheel alignment are
checked by monitoring the internal test circuits wired to the
central socket on the vehicle.
Current Consumer Tests: Includes items such as light
bulbs and the defogger heating coils. Because the power consumption at a given voltage depends upon the resistance of
the circuits, it is possible to learn a great deal from a resistance check. This is especially true when there are a limited
number of consumers in a circuit; for example, the stop light
circuit. In this case, if either of the two lamp filaments are
shorted or open, a significant and measurable change from
the standard reading will occur. Thus, the turn signal; parking, tail, and license plate lights; stop lights; and rear window
defogger circuits are all checked by passing a current through
the circuit, measuring the voltage drop, and comparing it
against the limits specified on the program card.
Battery Checks: Three checks are made on the storage
battery: (1) First, the battery voltage is read and recorded
without any load. (2) Then, a resistor is switched into the circuit to provide a temporary test load for a specified length of
time. Just before the load -time runs out, the battery voltage is
26

E2 29 30

DESIGNATES

MULTIPLEXER
CHANNEL
LOWER LIMIT
LOWER LIMIT
SIGN
UPPER LIMIT
UPPER

LIMIT

SIGN

4- MAKE -UP OF THE PROGRAM -CARD CONTROL WORD. A separate 32 -bit control word is
used for each of 60 different tests.
FIG.

PHOTOTRANSISTORS

25'

2R

15

4R

R2

SUM

16R

SIGN

BIT

FIG.

5- SIMPLIFIED

DIAGRAM OF DECODING CIRCUIT used to convert

a scaled analog voltage.

phototransistor signals into

and bit

23 the sign for the lower limit. Bits 24 thorugh 32 contain the upper limit value and its sign.

Automatic tests
During automatic tests, the system monitors and records
the status of the item being checked. These tests include items
such as turn signals, parking, tail, and license plate lights, stop
lights, defogger, battery, wheel alignment, starter perfor-

PROGRAM CARD is fed into card reader to

ready the system to check out the next car.

recorded and compared to the tolerance limits specified for

this test. (3) Finally, a built -in probe, normally immersed in
the battery electrolyte, provides an electric potential reading
to the computer. If the electrolyte drops to an unsafe level,
the probe is no longer in contact with the electrolyte. The
electric potential is missing from the probe, indicating a NoGO condition to the computer.
Front-End Alignment: The front -end alignment is measured automatically by optical /electronic equipment using
mirrors attached to the front wheels. A cross -configured light
beam is directed from a projector to the mirror attached to
the wheel. The mirror reflects the cross of light to the projector backing plate where it illuminates two rows of phototransistors, one row for vertical and one row for horizontal. The
camber and toe data are indicated by the shift of the projected cross in relationship to the location of the zero coordinates of these rows. By turning the steering wheel, the technician triggers the sensors and obtains a measurement having
an accuracy of five minutes of arc. The signals from the phototransistors are decoded and fed into the computer for evaluation.
Figure 5 is a simplified diagram of the decoding scheme
used to convert the phototransistor signals into scaled data for
processing and printing. The circuit features an adjustment
(R2) to compensate for different width workstalls in the various dealerships. Also, because the reflected light beam covers
two adjacent phototransistors, it is necessary to use a one-step
code to prevent inaccurate readings. The extended Gray code
was selected for this system. The characteristics of this code is
NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

39

that a change of the code word by one step causes a change of

only one bit. (Figure 6 shows sample bit configurations for
this code.)
The same data value will be recorded whether the plus or
minus phototransistor has been illuminated by the cross of
light, because the outputs of phototransistors having like val-

WEIGHT

STEPS
1

16

picting the power required to overcome the mechanical drag

inherent in the entire starting system and a superimposed accomponent which depicts the variation in starter motor current caused by cylinder compression.
The ignition circuit is grounded through a resistor during
this test to prevent the engine from starting. The starting
procedure is long enough to allow good engine rotation before the starter current test is triggered. At this time, the
starter current is read and four positive peaks of the ac -component are read and stored for evaluation. These peaks are
related to their respective cylinders by correlating them with
the trigger impulse sensor on the cylinder number one ignition cable. The lower limit of the peak values is automatically
checked and compared with the nominal values given on the
program card.
Dwell Angle Check: The dwell angle check is a measure
of the equivalent time during which the breaker points are

FIG. 6 -GRAY CODE is a cyclic code used to minimize errors when con
veiling analog quantities into binary form. This is a sample.

ues are oR -gated before encoding into the Gray code. The
output of all negative phototransistors are OR -gated to produce the sign bit.
The encoded signals are then converted to weightable binary code in a summing network. The resulting analog voltage is scaled to compensate for work stall width. The analog
voltage output of the summing amplifier changes synchronously with the steering wheel motions made by the technician. As the steering wheel is rotated, this analog voltage is
sampled and stored until called by the computer for processing.

COMPUTER PRINT -OUT tells mechanic and VW owner what needs to be

done to bring the automobile up to standard specifications.

LIGHT FROM PROJECTOR (right) is directed to mirror attached to front

wheel to check the vehicle's front -end alignment.

Starter and Compression Test: When the starter motor is activated, an analog voltage drop is developed in the
battery ground strap near the car body. This voltage drop is in
the order of millivolts and must be amplified before it is processed; however, it contains the necessary data to evaluate
starter motor performance and cylinder compression. This
analog voltage contains two components: a dc- component de-

40

RADIO -ELECTRONICS

closed. During this test, the ignition coil terminal is monitored and the resulting voltage surge caused by the ignition
points opening and closing is converted to a rectangular impulse. These rectangular impulses are integrated into a dc
voltage level, which is an analog voltage representing dwell
angle.
Regulator and Generator Check: At 2000 rpm the generator voltage is reached and the voltage ripple resulting from
the regulating process is smoothed out. Thus, when the engine
rpm reaches 2000, the voltage is sampled. An external resistor
is then switched into the generator output circuit to check it
under load. After a defined period, the voltage is sampled,

stored, displayed, and printed.

The Computerized Self-Analysis System marks a new
trend in automotive servicing. It aids the mechanic in diagnosing complex systems and prevents him from inadvertently
skipping items that should be checked. The result should be a
savings in time and money for the VW owner, as well as
greater confidence that his car is performing to standard specifications.

NOVEMBER 1972

www.americanradiohistory.com

R -E

VECOACOPES

This oft -ignored test instrument

has no peer in some phases of color TV

servicing. Get to know and use it.

How to use them

by ROBERT G. MIDDLETON

ALTHOUGH VECTORSCOPES HAVE BEEN

around for some time, few of us know

how they work, and how to use them in
TV troubleshooting procedures. Therefore, let's start at the beginning and take
it step by step.

There are several types of vector scopes, and as would be anticipated, we

can do more with the comparatively
elaborate instruments. Fig. 1 shows the
configuration of a basic vectorscope. It
is simply a cathode -ray tube with supply
voltages, operating controls, and capacitive coupling to the vertical and horizontal deflection plates. This arrangement has a deflection sensitivity of
roughly 35 volts peak -to -peak per inch,
depending on the screen size and type
of crt.

Basic Lissajous patterns

All vectorgrams are based on Lis sajous patterns. If we apply sinewave
voltages of the same amplitude and frequency, but with a phase difference of
90 to the vertical and horizontal deflection plates respectively, we expect to
obtain a circular pattern, as in Fig. 2.
However, in practice, the sinewave voltage applied to the horizontal deflection
plates (Fig. 1) must have somewhat
greater amplitude to form a circular
pattern, because the deflection plates
nearest the screen have less sensitivity
than the plates farthest from the screen.
Aside from practical details, a circular
Lissajous pattern corresponds to sine wave vertical and horizontal deflection
voltages that have the same frequency,
nominally the same amplitude, and a
phase difference of 90 .
Most vectorgrams have an elliptical
outline. Typical elliptical Lissajous patterns and their corresponding phase angles are shown in Fig. 3. We observe
that if the vertical and horizontal deflection voltages have the same amplitude, any ellipse that is formed will lean
45 with respect to the vertical and horizontal axes. Next, let us consider the
patterns that are obtained when the vertical deflection voltage is greater or less
than the horizontal deflection voltage.
These patterns are easily demonstrated

with a slightly more elaborate vectorscope; one that has vertical and horizontal amplifiers, in addition to the basic arrangement shown in Fig. 1. These
amplifiers are identical, and have a
bandwidth of 1 MHz.
If we start with a circular pattern,
and then advance the vertical gain of
the vectorscope, we get an ellipse (Fig.
4-a). On the other hand, if we start with

the phase angle corresponding to an el-

liptical Lissajous pattern. A quick

method consists of adjusting the vertical
screen deflection to equal the horizontal
screen deflection. As in Fig. 3, the vertical and horizontal tangents to the ellipse will then form a square. In turn,
the indicated phase angle can be approximated by comparison with the examples given in the diagram. Although
this is not a highly accurate method, it is
generally adequate for troubleshooting
chroma circuitry.
Sometimes we work with the basic
vectorscope arrangement shown in Fig.
1. In this case, the vertical and horizontal screen deflections cannot be readily
equalized. Therefore, the method of
phase-angle determination in Fig. 5 is
used. We center the pattern on the
screen, and measure the distances a and
b. In turn, the ratio a/b gives the sine of
the phase angle, and the angle can be
found from a table of sines. This is a
general and comparatively accurate
method. Note that the ratio a/b in Fig.
5 remains unchanged regardless of the

a circular pattern, and then advance the

horizontal gain, we get the elliptical

pattern shown in Fig. 4-b. Note that
these ellipses are either vertical or horizontal -they do not lean with respect to
the screen axes. Next, if we start with an
ellipse such as the 120 ellipse in Fig. 3,
and then advance the vertical gain of
the vectorscope, the ellipse will have a
greater height and will lean less than
45 with respect to the vertical axis. On
the other hand, if we start with the 120
ellipse as before, but advance the horizontal gain, the ellipse will be displayed
at less height, and will lean more than
45 with respect to the vertical axis.
There are two ways to determine
INPUT TO VERTICAL
DEFLECTION PLATES

Cv

MA.

2.2MEG

0.1 NF

INPUT TO HORIZONTAL

DEFLECTION PLATES
O

CH

2.2MEG

l
0.1 HE

DEFLECTION
PLATES
H

TO HEATER

TRANSFORMER

6.3V AC

DEFLECTION
PLATES

FROM
HV
SUPPLY

INTENSITY

250K
22K
100K

50K
1

HORIZONTAL
CENTERING

-780V

FIG.

FOCUS

250K

270K

1K

22K

15K

VERTICAL

-BASIC VECTORSCOPE configuration used to develop the CENTERING

familiar Lissajous patterns.

+420 FROM
LV SUPPLY O

NOVEMBER 1972

RADIO -ELECTRONICS

41

.'
I.
,.

laMffill&

w
- w
8

alii

III

13

12

1112

11

12

1011

0, 360

10

VOLTAGE APPLIED TO VERTICI

DEFLECTION PLATES

12

11

10 `
9

8
2

Y4
VOLTAGE APPLIED TO
DEFLECTION

RIZONTAL

11

10

8 9

30, 3300

3
1

11

F5__

10

892

60 , 300

10

FIG. 2- CIRCULAR PATTERN development. The numbers indicate corresponding points In time.

FIG. 5 (at right)-MEASUREMENT of phase angle

of deflection voltages Indicated by an ellipse. The
sine of a/b equals the sine
of the phase angle.

SIN

2
.s,--1

11

11

10

10

=b

X
12

5
6

90, 2700

12

11

10

10

4'8

DO W5

0'
FIG. 4

10',

110

4 5

3
2

A6

11

TIME

4
5

(below)- PATTERNS

10

formed by unequal deflection voltages with 90 or

270 phase difference. Vertical voltage greater at a,
horizontal voltage greater

0'

1112

i
1

a
7

at b.

0.Pi 4

MINF

b
5

ratio of vertical and horizontal signal

amplitudes.

10
9

150 , 210

A9

1011

12

12

Unkeyed rainbow signal

An unkeyed rainbow signal is the
simplest type of chroma test signal. It is
simply a 3.563795 -MHz sine wave,
which is 15,750 Hz less than the color subcarrier frequency of 3.579545 MHz.
In turn, an unkeyed rainbow signal
shifts progressively out of phase with
the receiver's color -subcarrier oscillator,
and the two signals pass through an inphase condition at the start of each forward- scanning interval. Fig. 6 shows the
basic test setup, and the normal vector gram that is obtained. In this example,
chroma demodulation takes place on
the R -Y and B -Y axes. A circular pattern is displayed normally, when the
vertical and horizontal signal amplitudes are equalized. Note that the "pie
cut" is produced by horizontal blanking
action in the receiver.
It is helpful to note some typical
trouble indications that may be observed. For example, a leaky capacitor
in the subcarrier phase-shifting network
causes demodulation angle to shift from

42

RADIO- ELECTRONICS

A
s.s, - -.
2

(a)

180

2
3
5

10'
(b)

'

12

of 90 That is, if the

hue control is adjusted to provide
demodulation on the R -Y axis, then
demodulation cannot occur on the B -Y
axis, and vice versa. Approximately half
of the hues are more or less distorted in
the reproduced color picture. In this situation, a vectorgram such as depicted in
its correct value

NOVEMBER 1972

www.americanradiohistory.com

3- LISSAJOUS PATTERNS produced by

various phase differences between horizontal
and vertical deflection voltages having the
same frequency and amplitude.
FIG.

7 pinpoints the trouble. That is, an

inclined ellipse is displayed, instead of a
circular vectorgram.
Various forms of nonlinear distortion can occur, due to defects in
chroma circuitry. For example, offvalue resistors or leaky capacitors can
cause incorrect bias voltages, with re-

Fig.

R-Y

VECTORSCOPE

(R -Y)

900

UNKEYED
RAINBOW
GENERATOR

41b,

-Y

DEMODULATOR
O V
B

180

OV
HORIZONTAL
BLANKING
INTERVAL

HORIZONTAL
BLANKING
INTERVAL

-Y

AS

+ (B -Y)

DEMODULATOR
2700

-R Y

FIG. 6 (above) -BASIC VECTORSCOPE TEST SETUP. Using an unkeyed rainbow signal. Circular
pattern results when vertical and horizontal signals are equal and receiver circuits are OK. FIG. 7
(right) -A TILTED ELLIPSE results when demodulation angle Is not 90 degrees.

"FLAT "

IN PATTERN

CLIPPED PEAK

HORIZONTAL
BLANKING
INTERVAL

VOLTAGE APPLIED TO
VERTICAL DEFLECTION PLATES

VOLTAGE APPLIED TO HORIZONTAL

DEFLECTION PLATES

FIG. 8- VECTORGRAM showing the results

of chroma signal clipping or compression.
Clipping on the R -Y axis as shown here
causes desaturation of colors making up

fleshtones.

HORIZONTAL
SYNC PULSE

FIG. 9 -THE KEYED RAINBOW SIGNAL Is similar to unkeyed

but the former provides more Information because the successive keyed bursts can be used to Identify ten chroma phases.

COLOR BURST

J
suiting compression or clipping of the
chroma signal. Fig. 8 shows a vector gram that results from positive -peak
clipping of the R -Y signal. This type of
distortion produces weakened or desaturated reproduction of the corresponding hues. In this example, the
flesh tones would be affected. The dis-

torted vectorgram identifies the fault,

and helps to locate the defective cornponent.

Keyed rainbow signal

A keyed- rainbow signal, as depicted in Fig. 9, has the same basic
characteristic as an unkeyed rainbow

signal. In addition, the keyed signal

provides more information, because the
successive bursts identify 10 chroma
phases. It is helpful to start with consideration of the same test setup as depicted in Fig. 6, but employing a keyed rainbow generator. In such case, the
ideal vectorgram that results is developed as shown in Fig. 10. Note that the
tops of the R-Y and B -Y bar signals fall
along a 15,750-Hz sine wave in the ideal
case, and the tops of the vectorgram
petals fall along the circumference of a
circle.
In actual practice, the tops of the
R -Y and B -Y bar signals do not have
sharp corners, but are rounded as depicted in Fig. 11. This corner rounding
results in rounding of the tops in the
vectorgram petals. As in square -wave or
pulse test work, corner rounding of
chroma-bar waveforms results from
limited high- frequency response. The
R -Y and B -Y bar signals in Fig. 11 are
idealized in that the pulse waveforms
have zero rise time. In practice, of
course, the rise time is slowed down to
an extent that is determined by the
bandwidth of the chroma circuits. It is
instructive to consider the situation in
which the bar signals have half -sine
waveforms. As shown in Fig. 12, the
vectorgram petals are formed of single
straight lines in the ideal situation.
This ideal situation may be partially realized in practice, as illustrated
in Fig. 13. Note that three of the vector gram petals approximate straight lines,
although the remaining petals have appreciable widths. There are some other
practical points to be observed in Fig.
13. First, only nine petals appear in the
vectorgram, while the ideal pattern in
Fig. 10-b has 10 petals. The "lost petal"
is due to a comparatively long horizontal blanking interval (slow horizontal
flyback). Observe also that the horizontal blanking interval appears in the upper right -hand part of the vectorgram in
Fig. 13. This is due to the fact that the
cathodes of the color picture tube are
driven by the chroma signal in this example.

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

43

15

HORIZONTAL
BLANKING
INTERVAL

R -Y SIGNAL APPLIED TO
VERTICAL DEFLECTION PLATES

(bl

R-Y

BURST

Y SIGNAL APPLIED TO
HORIZONTAL DEFLECTION PLATES
B

B-Y

l
.

t`

FIG. 10 -IDEAL KEYED -RAINBOW VECTORGRAM produced by

R -Y /B -Y demodulators. The complete pattern is at a (above). In
practice, two bars are lost during the blanking interval that produces the pie- shaped notch as at b (top right).

B-Y

e",
(b)

12- PETALS

ARE STARIGHT LINES (a)

when bar -signal phase Is as shown at b.
FIG.

-Y SIGNAL APPLIED TO
HORIZONTAL DEFLECTION PLATES

R -Y SIGNAL APPLIED TO
J VERTICAL DEFLECTION PLATES

NOTE: THE R -Y AND B-Y BAR

SIGNALS ARE IN PHASE
WITH EACH OTHER.

-HOW R -Y AND B -Y SIGNALS FORM PETALS ON THE VECTORGRAM. Signals on the deflection plates are In phase. The petals have rounded tops If the bar signals are rounded.
FIG. 11

RADIO- ELECTRONICS

R-Y

IlllftxvU

la)

44

.III II
nnnn

NOVEMBER 1972

www.americanradiohistory.com

Next, let us consider the case in

which one bar signal leads or lags the
corresponding bar signal slightly. For
example, we will suppose that the B -Y
waveform is moved slightly to the right
in Fig. 12-b, so that the peaks of the
R -Y and B -Y pulses no longer occur at
exactly the same instant. The result of
this shift is the formation of elliptical
petals in the corresponding vectorgram,
as depicted in Fig. 14. Again, let us suppose that the R-Y and B -Y pulses are in
exact time coincidence, but that the R -Y
pulses are slightly wider than the B -Y
pulses. The result is to change the
straight -line petals in Fig. 12 into widened petals, somewhat similar to those
seen in Fig. 13.
Another fact that we observe in
Fig. 13 is that the petals extend down to
the center of the vectorgram, where
they form a bright spot. This means that

the chroma circuits have adequate

bandwidth. On the other hand, if the
chroma coupling circuits have insufficient bandwidth, the center of the
resulting vectorgram is an "open circle ".

13- NORMAL VECTORGRAM for cathode driven color picture tube and the test setup
used to obtain It. Note that the horizontal blanking Interval is in the upper right quadrant. This
Is normal with cathode drive.
FIG.

KEYED
RAINBOW
GENERATOR

R -E editors

now CET's

J R

COLOR TV
RECEIVER

VECTORSCOPE

] G

JB

OGO

COLOR
PICTURE TUBE

O V

ANT INPUT
TERMINALS
CERTIFIED ELECTRONIC TECHNICIAN
s`olt1,1.EE11!y,oN'`

onra

NY."O 69

7-13-72

R-Y

J LARRY

...,.,.:,'

7ooy40a.

srCk
re.... ....61,41c
o..'..n

BY

BURST

FIG.

14- PETALS

when the

c.."n....

R -Y

or

Editor Larry Steckler is now the

proud holder of his CET certificate,
N.Y. #69. His comments on the CET
test -"It was more difficult than I expected it to be. I'd like to see every technician take the test and earn his certificate."

ARE FORMED BY ELLIPSES

-Y bars are delayed.

I his results from baseline curvature introduced into the R -Y and B -Y waveforms. In case the R -Y and B -Y channels have insufficient and unequal
bandwidths, the center of the vector gram is an "open ellipse".
Finally, let us consider the chief
distortions that appear in the vector gram in Fig. 15. Nonlinear distortion is
immediately apparent. For example,
the +Q petal is considerably longer
than the +I petal. Overload distortion
is evident in the tops of the -I, -(R -Y),
and +(G -Y) petals, in particular. By
way of comparison, the +(B -Y) petal
shows little or no overload distortion.
Nonlinear distortion is usually caused
by incorrect grid or base bias. Leaky
coupling capacitors are the most likely
culprits. To close in on the defective
stage, vectorgram patterns can be
checked back step -by -step from the picture tube to the chroma demodulators.
Vectorgrams are very informative
in chroma troubleshooting procedures,
provided that we know how to interpret
the patterns. There is more information
in a vectorgram than in a conventional
waveform, because a vectorgram is produced by sweeping one signal against

BLUE

GRNYEL

GRN BLUE

(BURST
PHASE)

270
-1R-Y)

FIG. 15- NONLINEAR DISTORTION Is evident

In the vectorgram at top. This Is indicated by
the fact that some bars are much longer than
others. Overloading Is indicated by the squaring -off of the tops of some of the petals- particularly those developing between 240 and 300
degrees. The drawing Illustrates chroma hue
and phase reference.

another. The most useful type of vectorscope provides vertical and horizontal amplifiers so that tests can be made
in low -level chroma circuits. Although
only the most basic points can be covered in the available space, the foregoing discussion should get the apprentice technician off to a good start. As he
gains experience in troubleshooting
with the vectorscope, many other test
techniques and pattern interpretations
will unfold.
R -E

CERTIFIED ELECTRONIC TECHNICIAN

43 -72

1A
e

~ip

.Y RE-

L7

Technical Editor Robert F. Scott

and his CET certificate, N.Y. #47. Bob
and Larry both conduct CET tests in the
metropolitan New York area regularly.

NOVEMBER 1972

www.americanradiohistory.com

RADIO-ELECTRONICS

45

NIS Home1raining in Electronics was the

start of something big for James Gunton

An NTS Graduate

James A. Gupton Jr. graduated from National Technical

Schools with a diploma in TV &

Radio Servicing. Today, he's a
mighty important man in the
world of Electronics!
Research associate with a
major electronics corporation;
author of numerous articles
in electronics magazines; an inventor with five patent applications to his credit. In the
field of electro- optics, he has
perfected a revolutionary
phosphor deposition technique
for cathode ray tubes.
Quite a tist of accompfish46

RADIO-ELECTRONICS

ments for a man who began his

career with an NTS diploma
and a job in TV & Radio servicing.
Any student can succeed
James Gupton is certainly an
exceptional NTS graduate.
He proves there's nothing to keep
a determined man from becoming a success in Electronics.
As he himself says, "Any student,
properly motivated, can
succeed in Electronics through
home- training."
Every NTS Electronics Course
is specially designed to keep
you motivated from"the time you

NOVEMBER )972

www.americanradiohistory.com

start building your first test

instrument until you're ready to
plug -in your solid -state Color TV
or other advanced electronics
equipment.

Exciting "Project Method"

Training
NTS Project Method Training
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You build advanced equipment while you learn Electronics
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Each week brings new
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For a man to become successful,

like James Gupton, he must have
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As an NTS graduate you have
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Electronics from the bottom up.
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And if you have the drive and
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I
I

49

step -by -step

Tv TROU!'
The sound module in a
IC and associated
by ART MARGOLIS

MHz sound trap into the third i.f. input.

Taking the sound off at the second i.f.
presents a problem. The sound is quite
weak and has to be beefed up before it
can be fed to the sound -detector. This is
done in the sound -detector amplifier. It
mixes the 41.25 -MHz sound carrier and
45.75 -MHz video carrier, producing an
amplified 4.5 -MHz sound output for the
detector. The sound- detector amplifier
acts like a third i.f. stage for the sound
only.
Next in line, in some sets, is a
sound module. In the Zenith it has five
terminals and a ground strap. Its heart
is an IC chip. Also in the module are inductive devices that cannot be installed
in an IC.
The chip is a "black box" type of
thing containing the detector and audio

THE SOUND CARRIER IN THE COMPOSITE

TV signal is troublesome. It is posi-

tioned only 920 kHz away from the

color subcarrier. When it mixes with the
color it produces a beat that can drive
right through the video amplifiers into
the color display. Just a tiny amount of
sound can do this. As a result TV engineers do everything possible to get rid
of the sound carrier before and after the
video detection. There is little or no
problem with the beat between the
video carrier and color subcarrier which
are 3.58 MHz apart.

Inside the sound module

In a typical solid -state color TV,
the sound pickoff can be in the output
second i.f. This permits placing a 41.25-

amplifier. The 4.5 -MHz output from the

sound -detector amplifier enters one terminal of the module and passes through
a 4.5 -MHz transformer.
Transformers or coils cannot be
formed inside a chip so they are discrete components on the module. The
4.5 -MHz sound -pickoff transformer is
conventional and picks the 4.5 -MHz intercarrier frequency out of the mess of
frequencies heterodyned inside the detector amplifier circuit. The 4.5 -MHz
signal is applied directly into the chip.
A limiter and an FM sound -detector are
inside the chip. The 4.5 -MHz and quadrature transformers and all other parts
VOLUME CONTROL CIRCUIT

47012

TO SOUND

MODULE
TYPICAL SOUND MODULE (ZENITH)
r

--

QUADRATURE COIL

FROM
SOUND
MODULE

.001

-1

2 7K

AUDIO
OUTPUT

12 pF

DETECTOR
AMPL
4.5 MHz
INPUT

1_NVb1il1,

VOLUME

CONTROL
VTVM

120 pF

00 Q o

pF

1
I

N.P.

)(

12

MIR

FROM

.0011

14

IC

VOL
CONT

LIMITING
DETECTION
AUDIO AMPL

5
7

I106 J_+

25V

.006T

10.

15

.0011

T
4701t

(.001

TO

05

VOL

CONI

-J

t24v
COMPLETE SCHEMATIC OF A TYPICAL SOUND MODULE. This one comes from
a lot more than just an IC to go wrong.

Zenith TV re-

ceiver. Note that there's

50

RADIO -ELECTRONICS

NOVEMBER 1972

www.americanradiohistory.com

CHECK THE SIGNAL leaving the module to find

out if it is operating.

shown outside the outlines of the IC

and discrete components on the sound
module.
The B -plus (24 volts) is applied
through a series resistor and is bypassed
with a couple of. capacitors, a routine
.05 and a 100-11F 25 -volt electrolytic.
The volume control and audio output
are hooked conventionally onto the
chip. Audio comes out of the chip.
Distorted or weak audio makes the
sound module a suspect. It has to be
tested, but how?
The first step is to eliminate the audio output stage and speaker by feeding

The sound module

SHOOTER'S GUIDE
solid -state TV set may consist of only a single
components. Here's how to troubleshoot it fast
an audio signal into the output stage
and listening for distortion. If all is well,
the trouble may be in the audio module.
The IC cannot be investigated on its
own. It must be tested with input and
output tests. You must apply signals
and by observing what happens to the
signal as it leaves the chip decide what
to do about trouble. The chip is tested
primarily for its ability to limit and detect the incoming FM signal.
Take a 4.5-MHz signal and apply it
to the sound -module input. Attach a
vtvm (on a low scale) to the module
output at the volume control. The unmodulated 4.5 -MHz input should pro-

duce little or no dc output voltage since

there is nothing to detect. Then vary the
4.5 -MHz generator frequency slightly to
either side of center. That sets up an imbalance in the FM detector, some dc
voltage is developed as if it was modulation. The dc scale will read some voltage either side of the center frequency.
If it does, the chip is detecting.
To test the limiting action, turn up
the output on the generator. Set the
generator frequency on one side of the
center frequency to produce a reading.
As the generator output is turned up,
the dc voltage will rise until it reaches
the limiting point of the chip. From
SYMPTOM

YES

- DISTORTED OR WEAK AUDIO,

there on in, turning up the output will

produce no more dc voltage. If this occurs, the chip passes its limiting test.
When you cannot cause detection,
limiting or both, the sound module is
the source of the trouble. Adjust the
cores in the sound i.f. and quadrature
transformers to peak performance.
Quite often the cores will be out of adjustment and by aligning the two cores
for good detection and limiting the repair will be made. Otherwise the problem boils down to, is the chip defective
or is a discrete component bad? The
trouble chart procedure leads to the suspects.

R-E

PIX OKAY

Volume control midrange. Inject audio tone at

module output. Good clear audio from speaker?

NO
Test audio

Inject modulated 4.5 MHz signal to module

input. Good clear audio from speaker?

output stage.
NO

YES

Conclusin -Module
has trouble.

Module is good. Test

detector amplifier.

Inject modulated 4.5 MHz signal between and

after input components: 6pF capacitor and
4.5 MHz transformer. Good clear audio at
either test point?
NO

NO

Conclusion -Chip or discrete

components contain defect.

B+ components have defect.

Test series 470 -ohm resistor

Test for +24 volts at chip B+

connection. Is it present?

YES

Between means bad 6 pF

After means bad 4.5 MHz
transformer. (Could be
misaligned transformer.
Try adjusting core.)

and .05 and 1001.1F bypass

caps.

YES
I

Conclusion -Chip itself or remaining discrete

components are suspect. Try limiting and
detection tests. Test setup, inject 4.5 MHz
unmodulated signal into module input.
Attach vtvm to volume control.

DETECTION TEST

Increase generator signal strength.

Dc scale reading increase only up
to a certain voltage and then stop
even if signal is further increased?

Vary frequency around 4.5 MHz

center. DC voltage increase?

YES

LIMITING TEST

NO

Try adjusting both 4.5 MHz

transformer and detection
coil. Do they cure?
YES

N
Detection
is

good.

Test chip, detection coil, 12 pF, 120 pF,

and .0068 pF capacitors, volume control
and its components.

NOVEMBER 1972

www.americanradiohistory.com

Lim ting
is

good.

RADIO -ELECTRONICS

51

starts to distort and then back off a hair.

Micropower on -off indicator

The absence of a power on -off indicator has long been a major disadvantage of solid -state battery-powered devices. Although the power drain
is so low that it has negligible affect on
battery life, it is still disturbing to find
that a battery-powered device has been
left on for days, or even weeks. The
light -emitting diode, or LED, is a miniature low- voltage, low -power device
that makes an ideal pilot light.
The circuit in Fig. 2 is a novel pilot
indicator recommended for installation
in a solid -stage vom described in Electronics Australia It runs off a 9-volt battery and draws an average of somewhat
less than 2 mA.

technical topics
Four off-beat circuit applications you can use.
Most unusual is the multivibrator-type i. f. sweep gen.
by ROBERT F. SCOTT
TECHNICAL EDITOR

SELECTING MATERIAL FOR THIS COLUMN

can be frustrating. We never know

whether the material selected will interest most of you. Some months back, you
indicated that you like Technical Topics
and want to see it more often. I have a
constant fear of saturating you with material that turns you off. This is your column so why make me play guessing
games? Drop me a line and tell me just
what subjects interest you and what
type of material you'd like to see.
We gather our material from application notes and limited-circulation and
foreign magazines so it may take a
while to work up material on your pet
subject. If enough of you tell me what
you want, we'll be able to get it and
even tell you when it will appear.
Meanwhile, here are a few circuits that
you may want to adapt for your own
needs.

the scope. It should be about 40,000

ohms for each 10 volts peak -to -peak of
sweep voltage. The output signal level is
controlled by a 3 -step attenuator and a
1000 -ohm pot for smooth control.
With the values shown, the multivibrator can be tuned from about 440 to
550 kHz. Frequencies as high as 20 -30
MHz can be covered using adequate
transistors and adjustments in circuit
constants.
When using the sweep generator,
set the scope sweep-speed control for
the lowest rate that can be used without
objectionable flicker on the trace. In
any event, the response curve will be
distorted if the sweep rate is too high.
Start with a very slow sweep and increase it to the point where the trace

BCI58

MV5023

2N3638

50824403

I
10K

1K

BCIO8

SEE TEXT}
T

2N3565

FIG. 2 -LED IS PILOT LAMP for ba tery-pow-

ered test Instrument. Transistor multivibrator

pulses LED for more brightness.
Q3

2.2K

6852

2.2K

1.8K

Unusual Lf. sweep generator

The response of i.f. strips, bandpass
filters and various forms of FM detectors can be checked and corrected, if
necessary, by using a sweep generator
and a scope. Most sweep generators

consist of an rf sinewave oscillator

whose frequency is swept about a center
point by a reactance tube, an Increductor (voltage -variable inductor) or
a variable-capacitance diode.
In a recent issue of Radio Communication, G 8CGA points out that a sine -

wave source is not necessary when

checking the response of high -Q tuned
circuits. The prime requisite is a signal
whose amplitude is constant over the
swept range. Fig. 1 is the circuit of a
sweep generator using a saturating -type
multivibrator oscillator. The frequency
is varied about the center point by applying a sawtooth voltage as bias to the
base of Q2. The sawtooth excitation
voltage is tapped off the scope's sweep
oscillator and fed to the common base
circuit through the DEVIATION control.
The value of resistor R 1 is determined
by the magnitude of the sawtooth from
52

RADIO -ELECTRONICS

D2

100

33K

15V

TUNE

vw
4.7K

10K

r/ D1

S2

47 pF

02

DEVIATION

56K
50

10K

15V

4.7K

4.7K

.01

2252

2.7K

OUTPUT j

SWEEP

INPUT

1K

R1

S1

.01

1K

4752

1K

(SEE TEXT)

4752

SCOPE

SAWTOOTH

SHIELD

L
01, Q2
Q3

= GE -7, HEP -641,

D1 =

D2 =
FIG.

1- MULTIVIBRATOR

BFX12, GE -12, HEP -52, ETC.

ETC.

6.1V ZENER
GE -504A, HEP -156, ETC.

SIGNAL GENERATOR delivers sweep signal for If. circuit alignment.

NOVEMBER 1972

www.americanradiohistory.com

9V

proper operation. If it is too low the circuit will not oscillate and the LED
won't light. Too high; both transistors
remain conducting and the LED lights

The LED, Monsanto MV 5023 or

Hewlett- Packard 5082-4403, is in the
collector load circuit of a multivibrator
that pulses the light on and off approximately 10 times per second. (LED's provide higher light output when pulsed
and the eye is more sensative to flashing
light so the pulsed LED makes an ideal
power -on indicator.)
The critical components in the circuit are the capacitor and the 150,000 ohm resistor. The capacitor must be a
low- leakage type such as a polyester or
metallized polyester. The 150,000 -ohm
resistor may have to be adjusted for

continuously.

Versatile lab power supply

A good wide -range power supply is
essential to every experimenter and service technician's workbench. One of the
most versatile we've seen was described
in Radio Elektronik Schau. It consists of
two identical 0 -25 -volt, 1- ampere supplies that can be used alone or switched
in series to deliver up to 50 volts dc.

450
1K

3055

Solid -state ratchet relay

A ratchet relay is normally specified when we need a sequential on -off

operation from a simple pushbutton
switch, as when operating a light or similar device from several remote points
or for the send-receive circuits of a two way radio setup.
The circuit in Fig. 5 is an electronic

05
2

R1

8.2K

47 pF

-T

P1

10K

35V

R2
1.2K

1.

15F1

0-25V

35V

4700p

The active circuits in the supply are

shown in Fig. 3. One of the supplies is
represented by the schematic, the other
by the block diagram. Voltage control
and adjustment is provided by the
CA3055 IC and 2N3055 transistor. Current and voltage can be read on built -in
1- ampere and 30 -volt dc meters. Figure
4 shows the switching that accounts for
much of the versatility of this instrument. S 1 switches the ammeter to
either supply when used separately
while S3 switches the voltmeter similarly. Slide switch S2 is used to connect
the two supplies in series for up to 50
volts output. A multiplier resistor (R1)
is switched with the meter to double its
range to 60 volts dc. The resistance of
the multiplier should equal the meter's
internal resistance.

B+

15V

CHANNEL

S1

+
D1

STARTEARTH
GROUND
FIG. 3 -BASIC DUAL POWER SUPPLY FOR LAB OR BENCH feeds two separate 25 -volt loads or one
load at 50 volts. Metering and switching circuits are Illustrated in the next figure.

STOP

RY1

OUTPUTS
+

S1

-CURRENT

CHAN

1- CHAN 2

125V

11A

RY1-3

O
3

S2

25V - 50V

50V

R1

o
2

S3

- VOLTAGE

125V

CHAN

CIRCUIT

FIG. 5- HYBRID SEQUENCING CIRCUIT. The

SCR latches on and off on consecutive closures of momentary switch Si.

TO CONTROLLED

- CHAN

o
30V
I

ratchet relay described in The Radio

Constructor. The device consists of a
SCR and a 500 -ohm relay with a pair of
spdt contacts and a normally open spst
contact to handle the load. The relay
contacts are shown as they are when the
SCR is turned off and the relay coil is
not energized.
When the pushbutton is first
pressed, a triggering pulse is fed to the
gate through relay contacts RY -1 and
RY1-2 and the SCR fires. The bottom
end of the relay coil connects to B+
through D 1, R3, S I and relay contacts
1

-o---frO- 0

50

FIG. 4-HOW SUPPLIES AND METERS ARE SWITCHED. Terminals indicated by circled numbers
correspond to those on the dual supply In Fig. 3. Switches may be slide, rotary or pushbutton types.

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

53

RY 1 -1 and RY 1 -2 so only a small portion of the SCR's anode current flows

through the relay coil and most of the
voltage is dropped across R4. Current
through the coil is too low to actuate the
relay.
As the pushbutton is released, gate
voltage is removed from the SCR and
the low end of the relay coil is no longer
tied to B +. The voltage across the coil
now rises high enough to actuate the relay, switching contacts RY I -1 and RY 12 and closing load contacts RY 1 -3.
The next time the switch is pressed,
the bottom end of the relay coil is
shunted to ground through the normally
open contacts of RY 1 -1 and RY 1 -2 and
a major portion of the SCR supply voltage is shunted to ground through R 1.
The SCR anode current drops below
the holding- current level and conduction stops. The relay is held in because the bottom end of its coil is now
connected to B- through the normally
open contacts and R I.
Releasing the pushbutton breaks
the circuit through the coil, releasing
the relay, opening the load contacts and
readying the circuit for the next operation.
The circuit can be checked for correct operation by metering the voltage
across the relay coil. It rises from zero to
4 volts when S I is pressed for START or
ON and rises to 11 volts when the button
is released. Voltage rises to 15 when the
button is pressed for STOP or OFF and
drops to zero when the switch is released.
A maximum current of about 50
mA is drawn when S1 is pressed to
START and then drops to 22 mA for as
long as the controlled device is on. Current drain is zero when the controlled
device is off.
Diodes D1 and D2 are small silicon
rectifiers. We do not have any technical
data on the type CRS1 /05 SCR but it is
a small plastic device in a TO -5 can.

Any low- current SCR should work

nicely.
Well, thats about it for now. Don't
forget to let me know what you'd like to
R -E
see in future columns.

But It Is an emergency, Officer. No picture,

weak sound, and there's a great football game
on this afternoon.

54

RADIO -ELECTRONICS

equipment

report

International Crystal's
FM- 2400-CH frequency meter

vaasal

Circle 13 on reader service card

THE

FIRST REQUIREMENT

FOR

A FRE-

quency meter is accuracy. The second is

ease of operation. The International
Crystal FM- 2400 -CH frequency meter
meets both of these with ease. Twentyfour different crystals can be used, covering all bands from 25 to 1,000 MHz.
For accuracy, each crystal meets or
exceeds FCC standards with a minimum
accuracy of 0.001 %. (The typical crystal is checked to an accuracy of
0.0005%.) Stability is 0.0005% between 32 and 122 F. The 25 to 54-MHz
vhf band, and high-band crystals are
calibrated to these standards. The uhf
band crystals (450 MHz band) are calibrated to 0.000125 %.
A special chart is provided for each
crystal. The FREQUENCY -ADJUST dial is
set to a correction factor determined by
the ambient temperature. An accurate
thermometer is provided, in the knob of
the FREQUENCY ADJUST dial. A vernier
on this scale allows setting to very close
tolerances.
For ease of operation, this is a
dandy. It's the simplest instrument of its
type that I've ever used. Measurements
can be taken with ease, on any kind of
transmitter. Coupling to the transmitter
isn't critical; the FM- 2400 -CH has
ample sensitivity to make usable read-

NOVEMBER 1972

www.americanradiohistory.com

ings without a lot of trouble.

All you have to do is place the instrument near the transmitter, check the
temperature and the chart for the desired crystal, and make the setting.
While you're doing this, the transmitter
is warming up. Push the key and note
the reading, with the frequency meter
set to RF; this is just to assure you that
there is a signal present. Only a small
amount of signal is needed to get an accurate reading. On the other hand, this
instrument will read fairly high signal
levels without trouble.
To read the actual frequency of the
transmitter, the dial is set for FREQUENCY DEVIATION, and both the transmitter and frequency meter are turned
on. The amount of frequency error is
read directly on the meter dial in kHz.
If the transmitter is right on the button,
the needle won't move.
Three different sensitivity ranges
are provided; X3, X1 and X0.3. The
meter reading is multiplied by the factor indicated, X0.3 being the most sensitive. You can find the exact frequency
of the transmitter, if it is off, by turning
the FREQUENCY ADJUST dial, and noting
which way you have to go to get the
zero -beat.
The FM- 2400 -CH can also be used
to check and align the receivers in any
system. Since the same crystal is used
for both transmitter and receiver testing, this makes accurate "netting" of
any system fast and accurate. (Netting
adjusting all receivers and transmitters
in a radio system to precisely the same

frequency.)
Since the FM- 2400's 24 crystals can
each be used for a single system, this allows the testing of 24 different radio systems without the need for more crystals.
Modulation of the transmitter can be
checked by noting the increase in meter
reading, in the RF position, when the
transmitter is modulated. An earphone
jack is provided on the panel for listening to it, or for checking zero -beat, etc.
The FM- 2400 -CH is powered by
two 6-volt NiCad batteries. A charger is
part of the "package." It is installed on
the bench, and the instrument can be
left plugged into it at all times. The
charging rate is regulated and the con (continued on page 102)

INSIDE THE RUFF GEN, a handy

test oscillator that you can build
to meet your needs. Parts are inexpensive and most are not critical.

SIGNAL GENERATOR
APPLICATIONS
An rf signal generator is much more than
a mere alignment tool. Here are some
uses that'll lead you to develop others.
By JIM HUFFMAN

THE SIGNAL

GENERATOR IS ONE OF

those everyday instruments that has literally thousands of applications. Thirteen interesting uses are described in
detail in this article. In addition, we will
show you how to build a basic signal
generator of your own.
The first group of eight generator
applications will primarily interest the
experimenter. Here we go:
1. Heterodyne Frequency Meter
Although the signal generator is a reliable source of known frequencies, it has
little value when checking the output
frequency of a frequency generating device such as an oscillator. By adding the
circuit shown in Fig. 1, you can convert
the signal generator to a heterodyne frequency meter. The unknown signal is
applied to the input of the frequency
meter and the signal generator is tuned
until the two signals zero beat. At zero
beat, you simply read the unknown frequency from the signal generator. Note:
when an rf heterodyne meter arrangement is being used, make sure you are
not reading a harmonic of the generator. It is a good idea to know the approximate frequency range for the unknown signal to insure a harmonic is
not being used. (Using the "Ruff Gen"
here eliminates the worry when using
the sinusoidal output.)
2. Grid Dip Meter The circuit
shown in Fig. 2 doesn't make the generator into an actual "grid" dipper, but it

does function in the same way. When

the loop is brought near a resonant circuit and the signal frequency is tuned to
SIGNAL
GENERATOR

RF /AF

the resonant frequency of the network,

the meter indicates a dip showing the
tuned circuit loading the output of the
signal generator. You can also connect

the generator output leads directly

across a tuned circuit and look for a rise
on a suitable ac voltmeter.
FIG. 1- HETERODYNE FREQUENCY METER.
The signal generator can be used as a heterodyne frequency meter with this circuit. The
.001 -F capacitors work at rf, while the .1-ttFs
couple audio. Make sure the unknown input
signal is about the same level as the rf generator output. Both should be somewhere between 0.5 and 1.0 volt.

AMPLIFIER /SIGNAL
TRACER

generator. Optimize L1 for your generator and

top frequency you wish to use.
TO RCVR INPUT (S -METER INDICATOR)
RF VOLTMETER, OR METERED
AMPLIFIER WITH RF DET.

IN34
OR

FIG. 2 -GRID DIPPER. You can find resonant

frequencies, unknown C and L, and many other
values when you add this circuit to a signal

EQUIV
I

N34

RED BLACK

OR

EQUIV
I

RED

.0011

0.11

0.1

.001

L1

3or4TURNS
2" DIA

'HOOKUP WIRE

BLACK

L
UNKNOWN
INPUT SIGNAL

DOTTED LINES

MINIBOX

FOR HAND -HELD VERSION

NOVEMBER 1972

www.americanradiohistory.com

- - - - -J

RADIO -ELECTRONICS

55

3.

Input /Output Impedance

Measurements By using the arrangement shown in Fig. 3, you can use the
signal generator to measure the input
and output impedances of amplifiers.
Fig. 3 shows how to measure input impedance. Variable resistor Rz is adjusted until the output voltage reads
one -half the maximum value. The value
of the variable resistor is measured at
this point and this value is approximately the same as the input impedance. Of course, this method does not
give the imaginary components of the
impedance.
Fig. 3 -b shows how the output impedance is measured. Again, adjust for
one half the maximum reading. This
Rz + SIG GEN Zo

AMPL Zin

SPECIFIED
LOAD FOR
AMPL

VOLTAGE

BAND

L1

Cl

80

5 pH
3 pH

500 pf
250 pF
25 pF
80 pF
50 pf
250 pF

40
20

15

10
8

MHz'

5 pH

.8 pH
.5 pH

2.5 pH

SPECIFIED AMPL INPUT

R9 +

(6 & 2 METERS)

GEN Zo

AMPL Zo

8.

transformer turns ratio is then 1:X. If

the output voltage (X) is 2 volts, the ratio is 1:2. If the transformer is a power
type, 60 Hz: in operation with 110 Vac
in, the output voltage would be 220 Vac.
You can also check transformer efficiency by connecting the signal gener-

MAXIMUM

21

of 2 kW linears.
Strobe Light Driver The audio
generator can be used as sort of a visual
tachometer in that it can be used to
drive a strobe light. When the generator
frequency coincides with the mechanical frequency, motion freezes. Don't
figure on stopping the motion completely, as the phase of the light and
motor drift somewhat. And don't forget
to convert revolutions -per- minute to cycles -per- second. Just multiply the audio
frequency by 60.
is fun in these days

ADJUST Rz SO THIS
IS

extremely stable and has no harmonic

output.)
7. Transmitter To the rf generator
with modulated output, you can add the
vfo circuit shown in Fig. 4 and modulate for an AM transmitter. This is a
milliwatt input job. The input to the
buffer stage can be held at less than 100
mW by adjusting the drive. This means
the generator can be used legally with
no license on the AM broadcast band,
Citizens band, or television audio. If
you hold a proper ham ticket, you can
use the outfit on the amateur bands for
a QRP (low power) rig. QRP operation

kHz. If the meter reading varies little

between these ranges, then the amplifier is essentially flat between the upper
and lower cutoff frequencies. On the
other hand, there may be points within
the 50 -100 kHz at which the voltage
drops to or below the 0.707 volts and
the output is not fiat between these
ranges. Make sure the output of the signal generator is constant, this may mean
occasional readjustment of the output
level of the generator.
5. Transformers Signal generators let you determine the transformer
turns ratio at the frequency for which
the transformer is designed. Merely insert the proper frequency at a given input level to the transformer, say, volt.
Measure the output voltage and set up a
ratio of input volts to output volts. In
the example: 1 volt to X volts. The

C2

C3

.01
.01

.1

.001
.001
.001

.005

.01

.01

.01

.001
.001

2N697
HEP 50, ETC.

- RZ

ADJUST Rz SO THIS
VOLTAGE IS 'A MAXIMUM
b

3- INPUT /OUTPUT

IMPEDANCE MEASURING. (a) above setup used to measure Z.

(for any 4- terminal network). (b) is the Z,.,,,
setup. In either arrangement, the signal generator must have adequate output to drive the amplifier under test.
FIG.

time the resistor reads the output impedance. This method will work for any
amplifier whether one-stage or multistage.
4. Frequency Response The signal generator can be used to measure
the frequency response of an amplifier
or network. Merely find the two points
at which the output voltage is 0.707
times the maximum value. In other
words if an amplifier's maximum output voltage is 1 volt and the generator
frequency is 50 Hz and 100 kHz before
the signal drops to 0.707 volt, then the
response is -3 dB from 50 Hz to 100
56

RADIO -ELECTRONICS

4- SIGNAL GENERATOR VFO. The signal generator makes a decent VFO with the addition of a
butter. 01 can be almost any npn transistor that will work at the highest output frequency you plan to
use. You can even use a pnp transistor if you reverse the battery polarity.
FIG.

ator to the primary, with the prescribed

load on the secondary. Now calculate
the power in the primary and secondary
(P = Ez /Z). Where Z primary is equal
to the load resistance times the turns ratio squared. Transformer efficiency is
given from %(Pout /Pi).
6. VFO Connect a buffer between
the rf signal generator and the input of
the transmitter (Fig. 4). The coil and capacitor LC are there to filter out
spurious outputs from your generator.
Coil and capacitor data are given in the
table. (Note. The Ruff Gen may be used
directly in this application because it is

NOVEMBER 1972

www.americanradiohistory.com

Technician applications
1. Check The Condition Of Capacitors Just connect the capacitor in
series with generator output and your
meter. Now sweeping the generator
from low to high frequencies should
produce low to high output voltage
variations. But if the output is constant,
the capacitor is open. If you have
trouble reading the outputs or cannot
detect changes too well, try connecting a
1000 -ohm resistor across the meter ter-

minals.
2. Inductor Checker Inductors
can be checked in the same *tanner as

capacitors. As the frequency goes up.

the impedance of the coil goes up, and
the voltage at the meter goes down. Use
the 1000 ohm resistor if you do not ohtain very substantial readings at first.
3. Sweep It If you don't mind going inside your rf generator, add a Varicap sweeper. This changes the frequency when a unijunction supplies a
variable sweep voltage. Fig. 5 shows the
schematic of such a sweeper. If you cannot gain enough sweep range, use a
IN5148 varactor.
4. FM Source With the circuit of
Fig. 5 and your rf signal generator you
have a source of FM that can be used to
check out FM receivers. The circuit
works on the same principle as the electronic sweep generator except consider
the input as audio and not sweep signals. The audio will be adjustable from
about to 2 kHz (ignore the sweep output to the scope).
5. Horizontal Bar Generator The
standard rf generator with 400 Hz signal
modulation will produce horizontal
bars on a television receiver. This signal
simplifies vertical linearity and height

FIG. 5 -SWEEP ANY RF GENERATOR by add -

+24V

ing this simple circuit.

47052
SWEEP RATE

1K

UJT HEP 310

OR E QU V

1K

001

10K

VV

ACROSS
TUNING
CAPACITOR

1N5144

VARICAP

15 -30 pF

RANGE
)E

001

SWEEP

OUT
TO
OSCILLOSCOPE

14V

L1

L2

1.5 -3

3 -7MHz

MHz

-a
BAND
S1

o
--0

Sr-

R13'
220K
D1

'SEE TEXT AND PARTS LIST

FIG. 6- COMPLETE SCHEMATIC OF THE

RUFF GEN. It is easy to build and produces all
the rf signals you are likely to require.

C18
365pF
TUNE

1N34
EQUIV

All capacitors silver mica unless noted

PARTS LIST

-360 pF
C2, C3 -.0015
C1

All resistors 1/2-watt 10% unless noted

R9- 100,000 ohms
R10- 24,000 ohms
R7 -4700 ohms
RB, R12 -330 ohms
-22 ohms
R13, R16- 220,000 ohms
R14 -1 megohm
R15- 470,000 ohms
R17 -2200 ohms
R18-200 ohms (5 %)
R19 -1000 ohms
R1,
R2,
R3,
R4,
R11

R5,
R6,

uF, at least 50V, ceramic

C4, C8, C15 -0.01 uF ceramic
C5 -100 pF
C6, C7 -750 pF
C9 -68 pF
C10, C11 -300 pF
C12, C13 -.005 uF ceramic
C14 -22 pF
C16 -2000 -F, 50 V, electrolytic
C17 -1000 /F, 15 V, electrolytic
C18 -365 pF variable (1 5 /16H x 1 %W x
113/16D). See text

www.americanradiohistory.com

01

OR

-1N34 or equal
D2-50 V, 1A, full -wave bridge
03 -400 mW, 12 - 13 volt Zener
L1 -27 turns B &W 3012 (Y." dia x 32 tpi)
L2 -34 turns B &W 3004 (Yz" dia x 32 tpi)
L3 -14 turns B &W 3004 ('/z" dia x 32 tpi)
01, Q2, Q3, 04 -2N914 or equal
05-15W silicon npn power transistor
S1 -2 pole, 3 position rotary (see text)
S2-double rocker switch (spst /spat)
T1 -24 V 500 mA transformer (sec), 117 Vac
(pri)
MISC -pert board, hardware, knob, 5 x 5 x 5
box, 3" dial, BNC Jack, grommets, line cord
D1

adjustment. Connect the rf generator

output directly across the TV's antenna
terminals. Then adjust the frequency
until the bars appear. Now adjust the
vertical linearity (and height) controls
till the bars are evenly spaced up and
down on the screen.

Building the Ruff Gen

Now that you have been introduced to some uses for the signal
generator, it's time to get one. If you
don't already have an rf signal generator, the Ruff Gen would be ideal. In
fact, some of the features of the Ruff
Gen might make you want to supplement your existing signal generator with
this one. The circuit was originally designed when a source of nearly sinusoidal rf energy was needed. If you have
ever used a commercial signal generator, you know that the output is anything but sinusoidal. Also, stability is
somewhat wanting in the cheaper commercial units so this rf generator also
fills this gap. Speaking of cheaper, we
have the third reason for building this
unit. It is less expensive than many
units.
Since the rf generator only operates
on fundamentals to about 15 MHz and
it is sometimes desirable to use it above
this range, harmonic generation capability is included. The normal sine -wave
output of the generator is distorted at

power on /off switch, the power supply

is "on" as long as the unit is plugged in.
The only real advantage here is the
creation of the heat from the regulator
which tends to stabilize the temperature
inside the generator. The heat also prevents moisture buildups when the case
temperature undergoes one of the rapid
excursions sometimes associated with a
garage workshop.
Since one of the primary considerations is that the unit be inexpensive,
the entire unit was designed around the
bargain pages of a mail -order catalog.
Almost everything needed can be found
there, excluding the case, etc.

Construction hints
Perf -board

is used

throughout, but

a printed circuit could easily be fabri-

cated since the wiring has no crossovers.

Three boards make up the unit.
They are the power supply, oscillator,
and amplifier boards. Each board is
mounted within the case on angle
brackets fabricated from a defunct utility box. Note the transformer mounting
method. The transformer was the
cheapest /best unit available, but there
appeared to be no way to mount it on a
board. Mounting was finally solved by
pushing some no. 22 solid hookup wire
through the holes at the four corners of
the transformer. The wires are simply
looped around and then soldered for a

T1

117 VAC

+14

ON/OFF
(N.0.1
+

FIG. 7 -POWER SUPPLY for the Ruff Gen. It is a simple, yet regulated supply. Note the unconventional position of the on -off switch. See text for explanation.

the flick of switch S2, harmonics can be

added when needed. This unit is not
modulated, but modulation may be
added if desired.
Three separate oscillators are used
in the unit for optimum performance.
The oscillators are basically Colpitts
types. Somewhere a trade -off had to oc -.
cur because of the multiband feature,
and this was in the tuning capacitor.
The same 365 -pF capacitor tunes all

three bands. Figure

shows the

scehmatic diagram for the generator.

Fig. 7 is the power supply.
Power for the unit is regulated by
an emitter follower voltage source; one
of the simplest regulators. Actually, the
greatest advantage is in the fact that
power supply ripple is held to a minimum (around 15 mV). There is no
58

RADIO -ELECTRONICS

very stable mounting method. No heat

sink is used for the power transistor,
since the power dissipated is no where
near the available 15 watts the unit can
dissipate at room temperature. On the
oscillator board the coils are merely
glued in place.
Then there is the issue of the
switches. In the interest of money; you

can order an assortment of rotary

switches, in hopes that you find one that
would work and restock the junkbox
with the rest. I had to remove an spst
on /off switch from the switch I used.
For only 99 cents, it was a worthwhile
experience and it paid off in the form of
9 additional rotary switches (and the
spst, too). Should you want to go the
more conservative route, you can
merely order the 2 -pole 3- position

NOVEMBER 1972

www.americanradiohistory.com

switch specified in the parts list.

The variable capacitor will have to
be raised in the air on a strip of aluminum I inch wide and 7 5/16 inches
in either side of
long. Bend the strip
center down to a 90 degree angle. You
should now have a U- shaped bracket.
Now put mounting ears on the bracket
by bending 'b inch of the ends away
from the center. Drill for the capacitor
and mount. There is actually three way
support for the capacitor. Two directions from the mounting ears on the
bracket and one way from the vernier
dial and capacitor shaft. This capacitor
is a common type. Radio Shack's No.
272-1344 looks good. Others can be
used with minor alterations in the mechanical layout of the generator.
The rocker switches should be
mounted on spacers to recess them in
the panel. I got the spacers from the rotary switch that was modified to make a
band switch. Letter the front, mount the
switches, and vernier, glue some grommets on the bottom for feet and you are
in business.

Calibration steps
Calibration is really no problem.
Just use the procedure for using the signal generator as a heterodyne frequency
meter (Fig. 1), borrow an rf generator
from someone and you are all set. Since
the ranges should have a slight overlap
any way, no attempt was made to add a
calibrate control. You can adjust the
value of R13 to achieve a more distorted output (more harmonics) if desired. In fact, there may be some merit
in making R13 a potentiometer to allow
a degree of harmonic distortion to be
controlled at the generator. For more
distortion of the lowest frequency oscillator, you would have to increase
coupling capacitor C 14 which is optimized at 22 pF.
The signal generator in one of its
many forms is a helpful addition to the
lab workbench. It can check the band pass of an amplifier, tuned circuit, mechanical filter, etc. It will do any of the
other things mentioned in this article
and many more that you might think of.
Certainly, constructing your own rf
generator is not as challenging as building a receiver, but the versatility of the
Ruff Gen should merit the little time
and effort that it takes to build it. The
Ruff Gen's output is nearly a sinusoid
so that it is extremely helpful in determining network response since there are
no harmonics to confuse what you see.
Harmonics may be added at will when
needed merely by switching the output
amplifier to a different amplifier mode
and thus increasing harmonic distortion.
At any rate, whether you build,
buy, or just apply; you will find the extremely handy signal generator a welR -E
come device on your bench.

the

state

of
SOLID STATE
Telephone answering devices, low-power consumption semiconductors,
COS /MOS price reductions, power hybrid Darlington, and more
by LOU GARNER
SEMICONDUCTOR EDITOR

THANKS TO SOLID STATE CIRCUITRY,

electronic equipment is invading indus-

trial areas which, before, were the exclusive province of electromechanical or

mechanical devices and, moreover, expanding into commercial businesses
where, previously, it had only a precarious toehold. According to economic
forecasts at an EIA (Electronic Industries Association, 2001 Eye St., N.W.,
Washington, D.C. 20006) conference
held earlier this year, the total U.S.
market for electronic equipment should
nearly double between 1975 and 1985,
reaching a total of over 80 billion dollars
by 1985. In contrast, total 1970 U.S.
sales were under 29 billion dollars.
One area where tremendous inroads are being made by electronic
equipment is in business offices. A few
years back, about the only electronic
equipment one would find in such offices -other than a personal radio -was
an intercom system. Some offices
boasted, in addition, electronic dictating
equipment. Today, however, even a relatively small office might have electronic data processing equipment, the
familiar intercom system, dictating and
transcribing equipment, an electronic
calculator, and an electronic automatic
telephone answering system. Where
part of the office staff may be assigned
to field work, the office might be
equipped with a two -way radio system
to maintain constant contact for information and reassignment purposes.
Currently, electronic telephone answering systems are enjoying a fairsized boom. More and more businesses
are installing these systems, including
professionals, such as physicians, attorneys, architects, accountants and engineers, real estate, insurance, stockbroker and construction offices, and
even retail and service establishments,

such as stores and repair shops. An automatic telephone answering system can
be worth its weight in gold to the radio TV service technician operating a one man enterprise. In addition to business
applications, quite a few systems are
being installed in private homes.
Retail prices range from about
$150 to over $700, plus installation, depending on the quality of the instrument and the operating features offered. Generally, the more expensive
the system, the greater the number of
operational options. All currently available systems feature solid -state circuitry
and all will answer a telephone automatically with a prerecorded message,
afterwards recording an incoming message for later playback. Most provide
for monitoring an incoming call while
recording.
The more expensive systems may
have an automatic counter for incoming
calls, two -way recording facilities for
outgoing calls, and even a remote query
option, permitting the owner to check
his accumulated calls from a remote
telephone.
Despite the seemingly simple functions provided by automatic telephone
answering equipment, their circuitry

can be quite complex, even rivalling

that of a color TV set.
By way of illustration, the unit
shown in Fig. 1, is a moderately priced
instrument that includes many of the
features found in more expensive systems. Unfortunately, space limitations
prohibit the publication of the in-

strument's complete schematic, but

some idea of its complexity can be
gleaned from its simplified block diagram, given in Fig. 2. The instrument's
power supply, alone, uses four diodes in
a bridge rectifier, a medium -power pass
transistor, and an IC operational amplifier to provide regulation. Altogether,
this device uses over 40 diodes, 35 transistors, 2 SCRs, and 4 ICs.
Various recording systems are used
by different manufacturers of automatic
telephone answering equipment. Some
use standard cassettes, others reel -toreel tapes, and still others special cartridges.
If you find automatic telephone answering equipment intriguing, have a
knack for solid -state circuits plus mechanical skill, and are an experienced
technician looking for other pastures or
even a hobbyist with an eye towards a
professional future, you may find it
worthwhile to investigate the rapidly
expanding field of office electronic

equipment installation and maintenance. It's a comer!

The merry MISER

FIG. 1- AUTOMATIC TELEPHONE answering

system; the Doro 311.

An interesting semiconductor device being offered by Lithic Systems,

Inc. (10010 Imperial Ave., Cupertino,
Calif. 95014) is a real miser when it
comes to its power requirements. Suitable for use in light flashers, relaxation
oscilators, tone generators and timing
circuits, the unit can operate with source
power drains measured at microwatt

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

59

which is generally similar to that of a

Unijunction transistor (UJT), but at
considerably lower voltage values. As
with a UJT, there is the customary positive resistance slope, peak point, negative resistance slope, valley, and upward
positive slope in the combination's performance curve.
Several of the MISER's interesting
circuit applications are shown in Fig.
4-a LED flasher at (a), tone generator
at (b), and low power dc/dc inverter at
(c). In each, the MISER is type LP 1000,
the power source B 1, a 3 -volt battery,
and the resistors half-watt units.
With the parts values given, the
LED flasher, Fig. 4-a, delivers a single
flash every few seconds. The total battery drain is less than 200 W. Almost
any standard LED may be used, including Monsanto's popular MV50. If
desired, the flashing rate may be raised,
but at the expense of increased power
drain. Simply reduce the value of series
resistor RI or raise the supply voltage.
If BI is replaced with a photovoltaic cell
(such as International Rectifier's type
S7M) and RI's value reduced to 5,000
ohms, the circuit operates as a lightpowered light.
You can use the tone generator circuit illustrated in Fig. 4-b as either a
low power code-practice oscillator or as
a metronome, simply by changing Cl's
value. A high- impedance loudspeaker
(20-ohm voice coil) is preferred for best
performance. If used as a code- practice
oscillator, Cl's value may be from 0.05
to 0.5 F, while up to 100 F, or more,
is needed for metronome rates.
In laboratory tests, the dc/dc inverter circuit shown in Fig. 4-c has supplied as much as 90 volts at microwatt
levels when powered by a small 3 -volt
battery. Step -up transformer TI is chosen for the output voltage needed, while
D I is a standard rectifier diode and C2 a
suitable filter capacitor.

B.

B.

LI
el

OUTGOING

MESSAGE

DRIVE
CONTROL
CIRCUIT

RELAY
LATCHING
NETWORK

SENSING

a2

v7

OSC

CONTROL
CIRCUIT

RECORDING
CONTROL
CIRCUIT

2-WAY

SWITCH

SW

c2

MOTOR

TONE OSC
CIRCUIT

REMOTE
CONTROL

o%-o

Pa

RELEASE
CIRCUIT

CIRCUIT

o
at

LINE
SEIZURE
CIRCUIT

o
T-2

PLAY
ANS

HEAD

ANS &
PLAY AMPI
VOICE

POWER
SUPPLY

ACTUATED
CIRCUIT

B+

RECORDING
AMPL

CI

PLAY
REC

HEAD

MONITOR
SWITCH

I`o

II
MICI

FIG.

2- SIMPLIFIED

C2

BIAS OSO
CIRCUIT

BLOCK DIAGRAM

of Doro 311

levels. In fact, it's actually called a

MI-

for Monolithic Integrated Stored

Energy Regulator. If teamed with a
standard LED, the unit can provide performance characteristics comparable to
those of a low- voltage neon lamp. Some
of its possible applications are truly fascinating -would you believe a light-powered light?
The MISER'S functional block diagram is in Fig. 3. It consists of a dcSER,

DC

COMPA RATOR

HI

POWER

GATE

&LO

THRESHOLD
LIMITER

ERASE

HEAD

automatic telephone answering system.

dc-comparator holds the power gate in

a high- resistance (non- conducting)
state, supplying a peak threshold voltage to its own non -inverting input. As
the capacitor's charge voltage reaches
the peak threshold, the dc- comparator
switches suddenly, biasing the power
gate to a low- resistance state and, at the
same time, changing the voltage at its
own non -inverting input to a lower
"valley" threshold. With the power gate
conducting, the capacitor discharges
through the external load until its instantaneous voltage drops to the new
valley threshold, whereupon the dc
comparator reverses its mode, turning
the power gate off and returning to its
original peak threshold voltage, permitting the entire cycle to repeat.
When a low resistance is connected
between the source (S) and load (L)
electrodes, the combination of MISER
and load have an overall characteristic

SPKR

FIG. 3-MISER FUNCTIONAL block diagram.

R1

comparator, high and low threshold

voltage limiters, and a power gate capable of furnishing output currents of
up to 50 mA. In most applications, the
device is used with an external capacitor
connected between its source (S) and
ground (G) terminals; the load, be it a
LED, loudspeaker voice coil, relay, or
transformer primary, is connected between the load (L) and source (S) terminals. Only one version is currently available, the LP 1000, supplied in a standard
3 -lead metal TO -18 package.
In operation, the capacitor between
the source and ground terminals is
charged slowly by an external dc power
source. During the charge period, the
capacitor's instantaneous voltage is constantly compared to an internal
threshold voltage. At the same time, the

60

RADIO -ELECTRONICS

4- TYPICAL

MISER APPLICATIONS a -LED flasher; b -Tone generator or code practice oscillator, c -power Inverter.
FIG.

NOVEMBER 1972

www.americanradiohistory.com

Commercially, the MISER may be

used in telemetry, biomedical, communications, alarm, and automotive applications.

Device /product news

Designated type TIS 125, a new npn
planar transistor designed for use as a
common-base amplifier in TV vhf rf applications has been introduced by Texas
Instruments, Inc. (P.O. Box 5012, M/S
308, Dallas, Tex. 75222). Illustrated in
Fig. 5, the TIS 125 features a high power

FIG.

-TI's

gain of

NEW TIS125 VHF transistor.

19 dB

and a noise figure of only

3.5 dB at 200 MHz. Offered in a TO -18

pin -circle plastic package, the new unit

has a low feedback capacitance of 0.3
pF maximum.
Good news from RCA's Solid State
Division (Route 202, Somerville, N.J.
08876) -general base price reductions

on its entire line of commercial

COS /MOS integrated circuits! The new

base prices apply to more than 180 standard types, including dual in-line plastic, dual in-line ceramic, flatpack and
chip configurations. Price reductions average 25 percent for plastic packages, 20
percent for dual in -line and flatpack ceramic types, and a whopping 50 percent
for chips.
RCA also has announced a variety
of exciting new devices, including a
high -current array, two new vhf /uhf
transistors, a high -power switching transistor, a hybrid dual Darlington amplifier, heavy -duty triacs, and three new
COS /MOS IC's.
Illustrated in Fig. 6, the new high-

with a common collector connection to

the mounting flange. External leads attached to either side of the package provide one common lead for six transistor
bases and another for the six emitters,
but the external leads can be sheared
apart to separate individual base or
emitter leads to form multi- parallel or
single- circuit combinations; if desired,
external crossover links may be added
to form single- or dual -Darlington configurations. With the six transistors connected in parallel, the TA8624 has a
switching capability of 300 amperes and
a dissipation of 1000 watts. It can be
used in such applications as dc motor
controls, converters, inverters, low -frequency high -power amplifiers, and
switching, series, and shunt regulators.
Designed for Class C vhf /uhf applications, RCA's new high frequency
transistors are silicon npn overlay devices. Designated types 40964 and
40965, the units feature high power
gain: 6 dB minimum tripling up to a
frequency of 470 MHz for the 40964,
and 7 dB min. at 470 MHz for the
40965. Both units are intended for use
in mobile and portable transmitters in
which intermediate power output is required at low supply voltages. They are
supplied in JEDEC TO -39 hermetic
packages.
Identified as type 2N6354, RCA's
new switching device is a 120 -volt, 10ampere silicon npn transistor intended
for such applications as switching-control amplifiers operated from 48 -volt
power supplies, power gates, switching
regulators, dc/dc converters, and power
oscillators. It is furnished in the popular
TO -3 package, and features an exceptionally fast switching time.
Supplied in a compact 14-lead dual
in-line package, as shown in Fig. 7,

FIG. 7 -RCA's TA8590 dual Darlington.

FIG. 6 -RCA's TA8624 300-ampere array.

current device, type TA8624, consists of

an array of six 50- ampere, hometaxialbase silicon npn transistors
mounted in a compact plastic package

RCA's new power hybrid device consists of two Darlington amplifiers, each
of which can deliver 5 amperes with a
current gain of 500, or 3 amperes with a
current gain of 600. The amplifiers include integral diodes for load -current
commutation and, therefore, are suitable for driving inductive loads. Typical
applications for the new hybrid, type
TA8590, are hammer driver, solenoid
driver, stepper-motor driver, and regulator service.
Intended for the control of ac loads
in applications such as heating controls,
motor controls, arc-welding equipment,

light dimmers, power switching systems,

and in air conditioning and photocopying equipment, RCA's new triacs are
rated at 40 amperes, 800 volts. Designated types 40925, 40926, and 40927,
the devices are supplied in press -fit,
stud, and isolated-stud packages, respectively.
RCA's new COS /MOS devices are

the CD4048A, CD4057A, and

CD4058A. Of these, the CD4048A is an
expandable 8 -input multifunction gate
featuring medium power TTL drive capability, three-state outputs, low -power
dissipation, high noise immunity, and
good temperature stability. Three binary control inputs select l -of-8 output
functions of eight input variables. The
eight output functions are OR, NOR, AND,
NAND, OR /AND, OR /NAND, AND /OR, and
AND /NOR. Through the use of multiplexing techniques it is possible to ob-

tain all eight functions during a given

clock time. With an "expand" input
permitting cascade operation to obtain
functions of 16, 24, or more variables,
the CD4048A is supplied in a 16-lead
dual in -line ceramic package.
The CD4057A is a flexible arithmetic array for use in LSI computers. It
provides 4-bit arithmetic operations,
time sharing of data terminals, and full
functional decoding for all control lines.
The device, furnished in a 28-lead dual
in -line ceramic package, can be used in
parallel arithmetic units, process controllers, remote data sets, and graphic
display terminals.
Finally, the CD4058A is an MSI 8stage fully static bidirectional shift register having parallel inputs and outputs
as well as serial JK inputs. Intended for

applications in code converters,

up /down Johnson or ring counters,

pseudo- random code generators (sequence generators), sample- and-hold
registers (storage counting and display),
and frequency and phase comparators,
the CD4058A is available in a 24-lead
dual in -line ceramic package.
Silicon General, Inc. (7382 Bolsa
Ave., Westminster, Calif. 92683) has introduced an upgraded industrial version
of its SG 1501 dual- tracking voltage
regulator. Identified as type SG4501,
the new device will accept inputs of up
to 30 volts, supplying 15 volts
within 5 %. Output voltage balance is
within 2% and line and load regulation
to 0.1 %. The device is offered in both
TO -100 10 -lead metal cans and 14-pin
dual in -line plastic packages. Its specified temperature range is 0C to 70 C,
and it has a maximum load current rating of 100 mA. The device alone can
power up to 25 op amps. External transistors can extend load currents to
above 2 amperes.
That concludes our look at solid
state for this month, my friends
have a happy Thanksgiving and don't
R -E
eat the wh0000le thing!

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

61

Using a Solid State

curve Tracer
Many important time- saving tests can be made
using a scope -curve tracer combination.
Here are some tests you will want to try
by MANNIE HOROWITZ

FIG.

1- TRANSISTOR -DIODE

CURVE TRACER plugged directly

into a scope. The output of this
tracer can be displayed on any

general -purpose scope.

horizontal amplifier chains. A typical

arrangement of scope and curve tracer
is shown in Fig. I.

THE TV OR HI -FI SERVICE TECHNICIAN

Transistor curves

uses a curve tracer to check the quality

of semiconductors when they are wired
in the circuit or as individual components. The hobbyist uses the instrument to select devices sold in a bulk
package that he may have purchased at
some "bargain" counter. The engineer
uses a curve tracer to note and check
characteristics of transistors and diodes

The collector characteristics of a

transistor can be displayed on the
screen of a curve tracer. Briefly, the col-

when he designs them into equipment.

Test and quality control technicians use
curve tracers to evaluate the grade and
type of device supplied by a vendor.
It is not presumptuous to state that
a curve tracer is so versatile, that it
serves some function to everyone involved directly in modern electronics. It
may be used in a different manner by
each individual, but the applications
overlap.
Some skeptic might stop here and
say, "I can do anything with my transistor tester that can be done with a curve
tracer." While it is true that there are
excellent transistor testers on the market, they will measure only a limited
number of characteristics of some devices, and these only at a specific collector current or voltage level. Using a
transistor tester, will in many cases, enable you to separate good devices from
bad ones. Yet you can know much more
about a device with but one glance at
the crt of a curve tracer.
It is easier to perform the tests and
measurements on the curve tracer if
your scope uses direct coupling (no input or coupling capacitors in the amplifier circuits) in both the vertical and

62

RADIO -ELECTRONICS

lector current flowing through a bipolar

transistor is dependent upon two factors-the collector to emitter voltage
and the base current. The traces on the
screen of a curve tracer display this information. Much can be learned about
the transistor from this display. A typical set of curves for an npn transistor is
in Fig. 2. The pnp transistor character-

VcE (VOLTS)

2- TYPICAL NPN collector display and

construction to determine characteristics of
bipolar device.
FIG.

istics are very similar -only the polarity

of the voltages and currents are reversed.
Each relatively horizontal line describes how the collector current, Ic,
varies with the collector -to- emitter voltage, VcE. The different horizontal lines
define this relationship for the various

NOVEMBER 1972

www.americanradiohistory.com

values of base current. For example,

draw a vertical line from the 6 -volt
point on the VcE axis up to the IB = 0.2
mA curve, and a horizontal line from
the intersection to the Ic axis. It crosses
the Ic axis at 6.5 mA. For this particular
transistor, when there is 6 volts between
the collector and emitter, and 0.2 mA
flows into the base, the collector current
is 6.5 mA.

The construction may be repeated

to determine the collector current at any
point on the characteristic curves. You
can determine bias requirements from
the display on the crt and make the necessary calculations to establish the desired idling current for the particular
transistor under test.
Beta can be determined from the
curves. Although it is not drawn as such,
the curves do not have to be evenly
spaced and the horizontal lines are not
always parallel to each other. Because
of this, beta will vary with Ic and VcE.
Beta is the short- circuit current
gain of the transistor. As you recall, two
types of beta are encountered -the dc
and the ac. Dc beta (BdC) is the ratio of
collector current flowing to the base
current causing this collector current, at
a specific collector-to- emitter voltage. In
the figure, at VcE = 6 volts, there is 6.5
mA of collector current when the base
current is 0.2 mA. Bd0 is 6.5 mA /o.2mA

= 32.5.
When ac signal is applied to the
base of a transistor, it forces the base
current to vary with the size of the input. In turn, the collector current will
vary with the base current. The ac beta,
Bay, is the ratio of these two variations
at specific collector to emitter voltages.
As an example, let us assume that the
signal causes the base current to change

from 0.1 mA to 0.2 mA and that VCE is

6 volts. The collector current will, in
turn, swing from 3.4 mA t 6.5 mA. Bac
is (6.5 mA -3.4 mA) /(0.2 mA - 0.1 mA)
= 31.
Alpha is the ratio of the collector
current to the emitter current. It is used
primarily when dealing with common base circuits. The ac alpha, aa,., and dc
alpha, adc, can both be calculated from
the respective betas using the equation

VGS

VGS=O
VGS =

Another important characteristic of

-0.5

=-

FIG.

1.0

VDS

VP

the transistor is the saturation voltage.

At the extreme left of the display in Fig.
2, note the curve at low collector voltages. The relatively vertical curve is inclined at a slight angle. The transistor
cannot operate to the left of the vertical
line. At the maximum collector current
of interest to you, draw a horizontal line
from the vertical axis to the highest base
current curve. Next draw a vertical line
from the point of intersection to the
VCE axis. The voltage on the VcE axis is
a good approximation to the saturation
voltage of the transistor.
From Ohm's law, resistance of any
device is a voltage divided by a current.
The ac collector resistance, rd, is the ratio of the peak -to-peak voltage to the
peak -to -peak current. The ratio is the
slope of a particular display. For the
transistor, the ac resistance varies with
the base and collector currents. On the
IB = 0.1 mA curve, the collector resistance around the le = 3.4 mA point is
(10 volts - 2 volts) /(3.6 mA -3.2 mA) =
20,000 ohms. This resistance is valid for
the common emitter circuit. For the
common base mode of operation, the
collector resistance is approximated by
beta multiplied by rd.
The ac collector resistance of the
vertical portion of the characteristic is
radically different from the rest of the
curve. It has been assigned the special
name of saturation resistance. Ideally, it
should be zero ohms so as not to limit
the minimum value of collector voltage.
In the figure, it is I volt /9 mA, or 111
ohms.
Leakage current and breakdown
voltage are important characteristics of
the transistor. Although they can be estimated from displays similar to those
in Fig. 2, they are diode characteristics
and can be determined by testing the
transistor as a diode.
FET curves are similar in form to
those of the bipolar transistor, except
that while the current steps are fed to
the base of the latter, voltage steps are
impressed between the gate and source
of the FET. A typical set of n- channel
curves are shown in Fig. 3.
The loss is the current flowing
when the gate -to- source voltage, VGS, is
zero. Vp is the pinch -off voltage and is

+1.0

VGS = +0.5

a
1

3- TYPICAL

N- CHANNEL DISPLAY and

construction to determine characteristics from

the display.

equal to the VDS (drain -to- source voltage) at the point where the VGS = 0
curve becomes horizontal. The zero gate
voltage transconductance, gmo is approximately equal to the ratio of the
difference in drain current, A ID, to the
difference in gate voltage, A Vos, causing the change in drain current. In the
drawing, the two VGs's are chosen at 0
and +0.5 volts. To avoid misleading
answers, do not choose values of VGS
greater than 0.5 volts for the calculation.
For p- channel devices, only the polarity of the voltages and currents are
changed. In either case, the transistor is
treated as a diode to test for breakdown
voltage and leakage current, Ioss.

Diode breakdown curves

As you know, diodes conduct readily when a voltage is applied making the
anode positive with respect to the cathode. Should the voltage be applied in
the opposite direction, only a small
will flow. The curleakage current,
rent will be large when the reverse voltage is increased beyond the breakdown
voltage, VB, of the diode. A curve showing this is drawn in Fig. 4.

It

VB
V

IL

iA

FIG.

4- REVERSE

BREAKDOWN CURVE of

solid -state rectifier.

Much can be learned from the

curve. The diode breakdown voltage is
at VB, the voltage that causes the curve
to turn from the horizontal. (This is also
the regulating or rated voltage of a zener diode.) The leakage current is IL,
the distance in microamperes from the
zero axis to the essentially horizontal
portion of the curve at the breakdown
voltage.
An extremely important character-

istic can only be seen on a curve tracer.

Diodes which can best withstand transient voltage pulses (and these pulses
can be extremely high), exhibit low resistance in the breakdown region. It is
desirable that the vertical portion of the
display be as near vertical as possible.
A good diode will be capable of
dissipating as much power in the reverse direction as it is permitted to dissipate in the forward direction. As a
rule of thumb, IR(max) = 0.7IF /VB,
where IF is the forward current rating of
the diode. When making tests, limit the
curve tracer so that the current through
the d'iode will not exceed the calculated
IR(max). The diode should, however, be
capable of conducting this current.
A bad junction can only be seen on
a curve tracer. The VB voltage should be

stable and not jump, however minutely,

from one value to another. Any jumping indicates a poor diode that should
be disposed of.
Leakage current and breakdown
voltages of a transistor can be determined using diode measuring techniques.
For the bipolar transistor, ICBO is
the reverse current that will flow between the base and collector when the
emitter lead is left disconnected. The
npn device can be checked by connecting the base to the anode terminal
of the diode jacks and the collector to
the cathode terminal. The leakage current at any particular voltage is Ice . If
you increase the voltage up to VR, you
can find the BVcRo or collector -to -base
breakdown voltage of the transistor.
To determine the ICEO of the npn
transistor, the base rather than the emitter is left open. The collector remains
connected to the terminal where you
would ordinarily connect the cathode of
a diode, and the emitter is connected to
the anode terminal. Leakage and breakdown voltage, BV CEO, are measured as
before.
In each case, the pnp transistor is
measured by reversing the connections
indicated for the npn device, on the
curve tracer.
The Ioss or leakage of an n-channel JFET is measured by connecting the
gate to the anode terminal on the instrument and the remaining two leads
to the cathode terminal. The leakage
and gate -to- source breakdown voltage
are measured in the same manner as the
equivalent factors of the bipolar devices. The drain -to- source breakdown
voltage can be checked on the curve
tracer by connecting the drain to the
cathode terminal and gate and source to
the anode terminal. Increase the voltage
until VB is reached. Of course, the connections must be reversed should a pchannel WET be tested
Diode breakdown measurements
also apply to the SCR. Just connect the
(continued on page 68)

NOVEMBER 1972

www.americanradiohistory.com

RADIO- ELECTRONICS

63

RCA Institutes Home Training may be

your best investment

for a rewarding
career in electronics

64

RADIO -ELECTRONICS

NOVEMBER 1972

www.americanradiohistory.com

LEADER IN ELECTRONICS

TRAINING
For over half a century, RCA Institutes, Inc., a subsidiary of RCA, has
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h n
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In the Master TV /Radio Servicing Program, you build and keep the all solid state black and white TV set, the color
TV set, the oscilloscope and the multi meter shown above.

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

67

SOLID -STATE CURVE TRACER

breakdown voltage in both directions

by simply reversing the connections of
the SCR to the curve tracer.

simple controls on the panel. A circuit

designer will undoubtedly use his ingenuity to accumulate a great deal more
information about a device under test
than is readily available at a glance.
Using the FUNCTION switch, you
can select the required one of the four
groups of displays that can be generated
by this instrument. Let's select and discuss one function at a time.

Forward diode characteristic

Transistors -signal types

(continued from page 63)

gate on the device to the cathode on the
device thorugh a 1000 -ohm resistor.

Then check the anode -to- cathode

All diodes have a distinct relation-

ship between the applied forward voltage and the forward current. These
curves tell much about the particular
rectifier or diode. A typical curve is
shown in Fig. 5.

Four current steps produced in this

instrument feed the base of the transistor under test. The steps are synchronized to the 60 Hz power supply frequency. Thus four steps are generated
during each cycle. Half -cycle pulses are
fed to the horizontal input of the scope
sweeping the trace four times each
cycle -once on the rise and once on the
decay of each half cycle. These half cycles serve two other functions as well.
First they are applied across the transistor to serve as the collector supply voltages. Second, they are fed to the step
generator so that the steps fed to the

FIG.

5- FORWARD

SCOPE

FIG. 6 -EICO MODEL 443 is a typical solid -

state semiconductor curve tracer.

------,

/
`(

VF

base of the transistor under test, will be

in time with the swept quarter cycles.
The emitter current of the transistor being tested flows through a resistor.
In bipolar devices, the emitter current is
just about equal to the collector current.
This current, a product of the base current and beta, flows each time one of
the four different steps is supplied to the
base. The voltage across the resistor in
(continued on page 96)

GNDO

VERTO

HORIZ

V
R15

R45

6852

CHARACTERISTIC curve of

solid state diode.

4S2,5W

CAL

R42
4S2,5W

The broken line is an extension of

the relatively straight portion of the
diode characteristic to the voltage axis.
It crosses the axis at VF. VF, is between
0.3 and 0.5 volts for junction germanium diodes and between 0.6 and 0.8
volts for silicon devices.
The resistance of a germanium
junction diode is lower than that of a
point contact signal device. You can
then separate the two devices by noting
that the slope of a junction diode is
more nearly vertical than that of a point
contact diode.
The relative size of a rectifier chip
determines its current carrying capacity.
The capacity may be estimated from the
type of curve shown in Fig. 5. At any
one current level, large devices will
have lower voltage drops than will
power rectifiers constructed with
smaller chips.

D1-D4
400 PIV, 750 mA
T1

O
TEST

L_,
6

117

6.3 VAC

VAC

15052

R17
33051

CAL

CD7

TEST

R47
150K

R28

R48+ R37

5.6K

i____J

15.6K

-AAA

PNP TRANSISTOR

UNDER TEST
C5

300/6V

C4
.47

.R32

)I+

90

180 270 360

5.6K

The EICO model 443 curve tracer

The FICO 443 curve tracer is
shown in Fig. 6. It can produce the
curves shown in Figs. 2, 3, 4 and 5, and
then some, when measuring semiconductor devices. The functional panel
layout allows the operator to readily use
the instrument. The technician just calibrates his scope using the calibration
voltages from the 443, and starts making measurements using a few of the

68

RADIO -ELECTRONICS

02

AAA

2N5355

R34+ 1133
6.28K

R29

--NW--10K
a

FIG. 7- CIRCUIT TO TEST SIGNAL TRANSISTORS is in (a). The negative cosine wave in (b) is used
to explain the formation of the four steps fed to the base of the transistor under test.

NOVEMBER 1972

www.americanradiohistory.com

R -E's Service Clinic

Troubleshooting
a novel approach
Imagination aids
troubleshooting by eliminating the mental rut
by JACK DARR
SERVICE EDITOR

This column is for your service

problems -TV, radio, audio or general and industrial electronics. We
answer all questions individually by
mail, free of charge, and the more interesting ones will be printed here.
If you're really stuck, write us.
We'll do our best to help you. Don't
forget to enclose a stamped, self -addressed envelope. Write: Service Editor, Radio -Electronics, 200 Park Ave.
South, New York 10003.

THIS MAY SEEM ODD, IN A TECHNICAL

column, but I'd like to go from technology to psychology for a while. Don't
worry; it has a real, practical application. It's about the use of imagination
in our work. The best diagnosticians
have a very vivid imagination, plus a
thorough knowledge of the circuit
they're working on. With both of these,
they are able to make up a list of the
many, many things that could be causing the symptoms they find. After this,
all they have to do is check out the list,
one item at a time, to find the cause.
Try it yourself, when you get a
spare moment. Get a defective set; any
kind. Also get a scratch -pad. Open the
set up, turn it on, and see what the main
symptom is. No picture, no high voltage, no sound, etc. Write this at the top
of the sheet. Now, sit there and make
up a list of everything you can think of
that could possibly cause it. Number
each item. You might start with the one
you consider the most likely and go on
from there.
Now start making tests. Check off
each item as you go. If your imagination is active enough, you will have all
of the possible causes on your list. However, I think you'll be surprised to find,
in many cases, that there were after all,
one or more things you forgot to put
down on your list.
I speak from a lot of experience. I
have used this method for a long time;
my shop is full of clipboards with notes
on 'em. You may he a bit embarrassed
the first few times. You'll find that you
forgot to put down what turned out to
be a very obvious cause, and this was
the one. After a little practice with this
method, I think you'll find your diagnostic skills sharpening up perceptibly.
By back -tracking, you will be able to
see where you got off the correct line.
Above all else, this will help you to
develop the most valuable attribute in
all diagnostic work -a completely open
mind The cardinal sin, of course, is the
"fixed diagnosis," made on the basis of
no evidence whatsoever; just what you
think it should be. If you commit this
error, you'll find yourself testing, not to
find out what the real trouble is, but

solely to verify your first opinion. (For

that's what this is; not a valid diagnosis,
but just a personal opinion, until you
have some hard facts and test results to
back it up.)
For a good horrible example of
this, you're sure that the loss of high
voltage and the high current in the horizontal output tube is due to a shorted
flyback. So, you change the flyback;
now, you still have high current and no
high voltage. Checking further, you find
that the focus transformer was shorted,
causing the whole trouble.
To use your imagination properly
you'll have to reverse the tradition of
the U.S legal system. Everything must
be considered guilty until proven innocent, by test. No matter how unlikely
a certain part may seem, suspect it until
you've proven definitely that it is good.
When you get this result, check that one
off your list and go on to the next one.
For another example, no high voltage, cathode current very low, screen
voltage on output tube very low. Tube
good, by replacement. Open flyback?
No, by ohmmeter test. B + supply at

bottom of winding normal, so the

damper is conducting. Imagination says
"This tube is acting as if it had no plate
voltage, but it's there on the flyback."
Final result: check plate lead; insulated
cap, looking good; wire not damaged.
Look inside the plate -cap, and find that
the wire has corroded and opened up.
No plate voltage.
For a final example, during WW II
I was servicing a B -25 bomber which
was ferrying through our field. It was
parked on a taxi -strip about half a mile
from the tower. I pulled the SCR -522
vhf radio, took it to the shop, changed a
tube, tuned it up, and called the tower.
Fine. Time, 12:00 midnight. At 3:00
AM, after two trips back to the shop,
and a perfect response, the radio still
would not work in the aircraft.
My test instruments showed that
the transmitter had ample rf output,
good modulation, and everything else,
but I could not get the tower. Mikes and
every other part of the ship's wiring,
checked. Since I had already tried cussing, I did the only thing left. I sat down

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

69

on the runway and cried.

Sitting there in the cold Texas
moonlight, Imagination finally came to
the rescue. From where I sat, I could see
the "ax- handle" vhf antenna on the bottom of the fuselage. Looking past it, I
could see that the antenna, the right
landing-gear strut and the tower were
perfectly lined up. I said, "Imagination,
shut up! That strut couldn't be splitting
the signal. It couldn't be!" Imagination
says "Try it. What have you got to lose
except more sleep ?"
I untied the tail tie -down, fastened
the rope to my jeep, and dragged the
tail of the aircraft about 5 feet to one
side. Crawling wearily back up into the

cockpit, I picked up the mike. "Rosy

Tower, this is Army 359. Radio check,
please." Back came a roar "Army 359, 5
by 5! Loud and clear!" "Thank you,
Rosy Tower! Army 359 over and out!

Goodnight!"
The moral of this is, of course, that
after you've exhausted all of the reasonable, normal alternatives, sit back and
let your imagination take it from there.
There must be something you haven't
thought of yet. Wind it up and let it fly,
and sooner or later you'll get it. If all
other ways have been exhausted, try a
vivid imagination. Remember, no idea
is too far -fetched to be worth investigating if all else has failed.
R-E

CHANNELLOCK
Gives You More

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SNIPS THAT CUT

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ON THE
FOURTH OF JULY

reader
questions
FLOATING BLUR

I've got an odd floating blur in a

Phiko 19KT51 chassis. It's about 6 inches
high, and floats slowly up the picture.
When the blur is at the bottom of the
screen, I can see video that should be at
the top of the picture, and vice versa.
A.M. Philadelphia, Pa.
Whatever it is, it is a "60 -Hz" pulse
(only one bar visible). Suggestion; put a
scope on the dc supply lines around the
video stage, and look for anything like a
60-Hz ripple or hash, pulse, etc. A
heater -cathode short in the video output
tube will cause the same kind of symptoms. In fact, any tube in the signal path, with a cathode resistor, and a
heater -cathode short can do it. I've seen
an rf amplifier tube cause similar symptoms.

WHITE FLASHES

I've got an old RCA CTC -9 color

chassis on the bench. Works like a charm,
with a few new tubes and a resistor or two,
and realignment But the set has an intermittent white flashing in the picture. The
whole picture will go very bright, and out
of focus a little, then go back to a good
color picture. Long -term intermittent. I'm
afraid to take it back until I find this.

don't need the grip of a gorilla to cut

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L.H., Honobra, Okla.

This is caused by something that is
affecting the video(Y) signal, or, you
could say, the brightness level. The pix
tube cathode voltages are going negative (which makes the picture tube go to
higher brightness) then falling back, to
normal.
The most likely cause for this is an
intermittently-leaky or shorted 12BY7
last video output tube. Try a new one
here. While you're there, clean the
socket contacts and check all of the PC
board conductors for breaks.
VERTICAL BLINK

I've got an Airline color TV in for

service. The raster will collapse to a very
thin line, then slowly fill up again. Action
is pretty fast. This is a GEM- 17148B
chassis, and I can't find a listing in the
Sams file. The vertical tube (13GF7) is
OK, and the dc voltage supply is OK.

MEADVILLE, PA.

16335

Circle 15 on reader service card

70

RADIO- ELECTRONICS

NOVEMBER 1972

www.americanradiohistory.com

R.D., Vinita, Okla

For a schematic, check the "Sharp
CN -52T ", Sams Set 1076 -2. This is
practically the same, especially in the
vertical circuit. (Airline made by Sharp,
in this one)
Check the cathode voltage on the
vertical output; pin 3 of the 13GF7. If it
is jumping up and down, turn it off, and
check for - continuity to ground. Should
read 1470 ohms; a 470 -ohm resistor on

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Illl:L1
r

3.
4.
5.

Model 925

$'349.430

$79.00

Model 925 ELECTRONIC TOTALIZER

Frequency range, from dc to

6.
7.

-MHz, or dc

to 100 Hz (internally switch selectable) with

totalizing count from 0 to 99,999. Trigger
level Is automatic, and a pushbutton switch
on the front panel resets the count to "0 ".
Same dimensions as the 915 and fully com-

patible with the other compact instruments

in this line.

8.

FULL MULTIMETER CAPABILITY. DC volts, AC volts, DC current, Kt2

measurements, all built in.
HIGH ACCURACY. .1% 1 digit on DC volts, Kt2 and current functions. 1% 1 digit on AC volts.
100 dB COMMON MODE REJECTION.
HIGH SPEED READINGS. Up to 10 readings /sec.
BRILLIANT IN -LINE DISPLAY. 25,000 hour life for numerals, decimals
and function displays.
PORTABILITY. Light weight, 1/2 rack size.
UNIQUE CURRENT MEASUREMENT CIRCUIT. 10 mV maximum voltage
drop.
LOW, LOW, COST.

Be sure to check the great bargains in our Mini -Line, too. All Mini -Line
prices are for fully assembled instruments.
Mail this coupon now. or call us direct: (213) 341 -0800!

ORDER COUPON

DVINIASCIIENICH
9601 CANOGA AVENUE, CHATSWORTH, CALIFORNIA 91311

TELEPHONE (213) 341 -0800

TWX 910- 494 -1951

Company

Okay, know a bargain when

Deliver (Model(s)
My Check #
I

My

Title

Name

TELEX 67 -3382

see one.

to me ASAP.

Name_

Address

is enclosed.

enclosed

will follow.

City

State

NOVEMBER 1972

www.americanradiohistory.com

Zip

RADIO- ELECTRONICS

71

the PC board near the socket, and a

1000 -ohm resistor (a 2 -watt film type).
The last one is probably opening intermittently.
By the way; this 1000 -ohm resistor
is completely inaccessible unless you
pull the chassis. It's in a group of similar
resistors to the left and below the opening you see by taking off the bottom
plate. Trace the circuit from the 13GF7
socket to the 23JS6 (horizontal output
tube) socket. You'll find a thin green
wire going to pin 4 (suppressor) and
then going on over to the 1000 -ohm resistor. Quick- repair, just clip the wire to
the original resistor, and solder a 5 -watt
wirewound 1000 -ohm resistor from the
lance on the PC board (bottom of the
470 -ohm resistor) to ground. There is
plenty of room for this in here. Use spaghetti on the leads.
POOR HORIZONTAL SYNC
I've got a Zenith 14N22 chassis with
very poor horizontal hold action. From
the solder joints, it looks as if there has
been some "work" done around that circuit. I've checked all of the capacitors,
and so on, with no results. Where do I go
from here? -F.S., Acorn, Ark.
Check the apc diodes. If they have
been replaced, it could be that someone
used a poor grade of diode, or that one
of them is leaking. The scope photo
shows you what the sawtooth will look

like when this happens. (or it did on the

last one of these that I found.)
This waveform reads about 4 volts
peak-to -peak, and it ought to be about
17 volts. Note the distortion; it also

cured the trouble.- Gerald Oium, Towner,

N.D.
Duly noted and filed! Thanks, Gerald. Found a lot of hash on the B +
when you scoped it, didn't you?
COLOR PROBLEMS?

In a practically new Motorola Quasar II TS -929 color set, I had what looked
like agc problems. On weak stations I got
a picture. On a strong signal the raster
went out. Left small "sparkles" of light, so
I knew it wasn't the high voltage. I adjusted the i.f. agc control, and now I have
a good monochrome picture.
However, I have a weird color prob-

shimmered so badly that it was hard to

photograph. Try a new pair of diodes,
and check them for balance and reverse
leakage before you put them in!
HORIZONTAL OSCILLATOR
FREQUENCY PROBLEMS
In a recent Service Clinic, you had a
question about a horizontal oscillator running too high. I found the same kind of
trouble in a Zenith 14M23. It whine4
with no picture on the screen. Tracing the
B + lead back from pin 1 on the horizontal control tube, a 6GH8, I found that
C44B, an 80 Al' electrolytic capacitor in
the B + supply was open. Replacing this

lem. When I turn the color (intensity) control up, I get big horizontal bands of oversaturated color. However, in between
these are bands where the colors are
locked in the right places on moving objects. I scoped the color demodulator (IC)
and color amps, etc., with a color-bar sig-

naJ and I got the right patterns jittery,

but OK. All keying pulses are OK, agc
and alL I think this is agc, but what?
R. G., Baltimore, Md.
Right! This is an agc problem, but
one of adjustment. The i.f. agc control
on these sets is pretty sharp, and hard to
hit, unless you're very careful. This condition can be caused by the agc control
being set too far toward the "blackout"
end. Move the control back to a "white (continued on page 78)

I(1TfRNATIONAL

Fteqiency
gi FM-2400CH
Tests Predetermined Frequencies 25 to 1000 MHz
Extended Range Covers 950 MHz Band
Pin Diode Attenuator for Full Range Coverage
as Signal Generator
Measures FM Deviation
FM-2400CH provides an
accurate frequency standard for
Iwo
testing and adjustment of mobile
transmitters and receivers at predetermined frequencies.
The FM-2400CH with its extended range
covers 25 to 1000 MHz. The frequencies
can be those of the radio frequency channels
of operation and /or the intermediate frequencies of the receiver between 5 MHz and
The

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Frequency Stability:

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crystals (less temper18.00 ea.
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IF crystals

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from +25 to +125 (.000125% special 450
MHz crystals available).
Self- contained in small portable case. Complete
solid state circuitry. Rechargeable batteries.
WRITE FOR CATALOG!

72

RADIO -ELECTRONICS

$595.00

RF crystals (with temper-

40 MHz.

NOVEMBER 1972

INTERNATIONAL
CRYSTAL MFG. CO., INC.
10 NO LEE

OKLA. CITY. OKLA. 73102

Circle 17 on reader service card

www.americanradiohistory.com

Universal tap simplifies MATVdesign

by Bert Wolf
Manager Jerrold DSD /ECSD Division

Until now, MATV system design

has been somewhat complex. You had
to calculate losses in decibels and
specify a fixed tap -off isolation value
at each receiver location.

The new Jerrold OMNI -TAPs have

changed all this. OMNI -TAPS are universal. That is, any OMNI -TAP can be
used anywhere in any MATV system.
The secret is adjustable isolation,
which you can vary simply by turning
a screwdriver after the system has been
installed.

PARALOG PLUS
ANTENNA

3550

GIBRALTAR
AMPLIFIER
1596A
SPLITTER
1597

SPLITTER

Aside from simplifying system

design, OMNI -TAPs also reduce your
inventory problems. Since OMNI -TAPs
can be varied continuously over a 12
to 25 dB range. one type of OMNITAP replaces three types of conventional tap -offs.
Figure 1, for example, shows a
typical 8 story apartment house, older
school or hotel, with eight TV outlets
per floor. OMNI -TAPs are used for
every TV outlet. Because tap insertion
loss is very low (average about 0.6 dB
per tap at VHF), isolation is adjustable, and Jerrold CAC -6 cable loss is
minimal. (3.2 dB /100' at VHF), your
system calculations are greatly simplified. Just use a Jerrold Gibralter 3550
amplifier, fed by a Paralog Plus antenna. A new motel or school would
be similar, except that trunklines
would be run horizontally.

If your particular system is smaller,

reduce the number of trunklines and
tapoffs, but nothing else. The 3550 is
economical enough even for small
systems. If the system is bigger, add
trunklines and tap -offs, but nothing
else. The 3550 can easily handle up to
100 OMNI -TAPs. (For systems over
100 tap -offs. use the 3661 or 3880.)
Choose the antenna as you would
an ordinary home TV antenna, except
that it usually pays to choose the next
larger model. If signals are weak,
simply add

Powermate preamplifier.

FIGURE
X

maximum attenuation. Then, go to

a tap in the middle of the trunkline
and make sure you can read at least
1000 microvolts of picture carrier
signal on the highest channel the
system carries. If the reading is less
than 1000 microvolts, turn the
OMNI -TAP counterclockwise until
you get 1000 microvolts. Repeat
for each tap until you get to the
end of the line.

Adjusting
Omni -Tap Isolation
Once the system is installed, you
have to make sure it works properly.
In many cases, no adjustments will be
necessary. The OMNI -TAPs will work
fine in the system just as you receive

them.
With an Ohmmeter. Connect the
Ohmmeter between the arm of the
OMN1 -TAP potentiometer and the
center conductor of the tap output.
Set the first four OMN1 -TAPS in
each trunkline (nearest the Head
End) to 700 ohms. Set the next
two OMNI -TAPs in each trunkline
to 500 ohms. Then, reduce each
tap -off in the line by 100 ohms
until you get to the end of the line.
2.

In large systems. however, you will

have to adjust the OMNI -TAPs so that

they provide more isolation near the

Head End amplifier than they do at
the ends of the trunklines.

There are two ways

OMNI -TAP isolation:

to

adjust

Figure is a VHF -only system. But

adding UHF channels is no problem.
Simply use a VU- FINDER PLUS antenna instead of the PARALOG PLUS.
and a 4400 82 channel amplifier in
place of the 3550. No other changes
are required because the OMNI -TAPs.

I. With a Field Strength Meter.

such as the Jerrold 747. You should
have a Field Strength Meter for
MATV work anyhow, and this is
the easiest way to adjust OMNI TAP
isolation.

the splitters and the cable can handle

UHF frequencies with no difficulty.

by turning all of the

OMNI -TAPs fully clockwise. for

Start

For help in laying out

solving specific system

system or
problems,
contact Jerrold via your local Jerrold
a

distributor.
Or, for more information on MATV
systems. write Jerrold Electronics,
P.O. Box A. Philadelphia. Pa.

Circle 18 on reader service card

NOVEMBER

1972

RADIO -ELECTRONICS

73

New kits for every interest in

Kit
(A1 -1214

AR -1214

16995*

Tuner & AA -1214 Amp, 89.95* each)

New Heathkit
50 -watt Stereo Receiver
The new Heathkit AR -1214 AM /FM Stereo Receiver comes on with a great new look that's as
practical as it is beautiful and the AR -1214 is a
work of Heath audio excellence throughout. The
amplifier section produces a clean 25 watts IHF,
15 watts RMS, per channel into 8 ohms. Two integrated circuits and two ceramic filters in the
IF give this receiver a selectivity greater than
60 dB and superior amplifying /limiting characteristics. The phase lock multiplex demodulator
gives 40 dB typical channel separation at less
than 0.5% distortion. The preassembled FM tun-

Kit

Heathkit Stereo
Cassette Deck

12995*

stereo cassettes, including chromium- dioxide.The built -in record

bias adjustment requires no ex-

ternal equipment, utilizes the

front -panel meter and a built -in

reference. Features include precision counter, automatic motor

shutoff, preassembled and aligned
transport mechanism. Compatible
with any quality mono or stereo
system. 12 lbs.

Kit

SB -313

Kit

33995*

New Heathkit
SB -313 SWL Receiver
Covers 9 switch -selected bands
between 3.5 & 21.8 MHz; receives
SSB, CW, and AM with professional quality. 5 kHz AM crystal

filter supplied, separate SSB & CW

crystal filters optional. Solid -state
circuit including 4 MOSFETs. IC

crystal calibrator provides markers every 100 kHz or 25 kHz. Plug in boards & wiring harness simplify assembly. 22 lbs.

HW -7

your local Heathkit

Electronic Center
send for FREE catalog

__

6995*

New Heathkit
HW -7 CW QRP Transceiver
Work the globe on "flea- power"
with this 3-band QRP CW transceiver featuring VFO & provision
for xtal transmit operation. Covers CW portion of 40, 20, & 15
meters. Solid -state circuit. Sensitive Synchrodyne detector. Built in sidetone& relative power meter.
Operates from optional AC power
supply (14.95 *) or 12V batteries.
6

lbs.

See them all at

RADIO -ELECTRONICS

day. 16 lbs.

AD -110

The AD -110 Stereo Cassette Deck

offers a typical frequency response of 30 -12 kHz for full fidelity reproduction of all mono and

74

ing unit provides 2 uV sensitivity and a 2 dB capture ratio. The phono preamp section also uses
integrated circuitry and has its own level controls so turntable volume can be set to coincide
with tuner levels. All this in a money- saving kit
project that's a pleasure from start to finish.
Most circuitry mounts neatly on just three printed boards. The FM tuner is preassembled. Three
evenings and just four simple alignment adjustments will have it all together. And the cabinet
is included in the low price. Other features are:
Black Magic panel lighting to hide the dial face
when the receiver is off; flywheel tuning; stereo
indicator light; headphone jack; speaker on /off
button; built -in AM antenna. And there are complete tape monitor facilities so you can hear
recorded material as it is committed to tape,
make use of the many add -on components that
use these jacks, or combine your AR -1214 with
the matching AA -1214 Amp for a great sounding
4- channel system at a nice price. Stereo "separate" versions of the AR -1214 are also available:
the Ai -1214 AM/ FM Stereo Tuner at 89.95 *; and
the AA -1214 Stereo Amp at 89.95 *. Both prices
include cabinets. For a bold new sound in your
listening room, order your Heathkit AR -1214, to-

HEATHKIT ELECTRONIC CENTERS ARIZ.: Phoenix,

2727 W. Indian School Rd.; CALIF.: Anaheim, 330 E. Ball
Rd.; El Cerrito, 6000 Potrero Ave.; Los Angeles, 2309 S.
Flower St.; Pomona, 1555 Orange Grove Ave. N.; Redwood City, 2001 Middlefield Rd.; San Diego (La Mesa),
8363 Center Dr.; Woodland Hills, 22504 Ventura Blvd.;
COLO.: Denver, 5940 W 38th Ave.; CONN.: Hartford
(Avon), 395 W. Main St. (Rte. 44); FLA.: Miami (Hialeah),
4705 W. 16th Ave.; GA.: Atlanta, 5285 Roswell Rd.; ILL.:
Chicago, 3462 -66 W. Devon Ave.; Downers Grove, 224
Ogden Ave.; IND.: Indianapolis, 2112 E. 62nd Ave.;
KANSAS: Kansas City (Mission), 5960 Lamar Ave.; MD.:
Baltimore, 1713 E. Joppa Rd.; Rockville, 5542 Nicholson

NOVEMBER 1972

www.americanradiohistory.com

the new free Heathkit catalog

Heathkit GR -900 25V TV...the most
exciting set we've ever offered!
UHF /VHF detent power tuning heads up an impressive list of GR -900 deluxe features. Push a
button and you scan either UHF or VHF channels,
in either direction, with detent action locking in
on the 12 VHF and any 12 preselected UHF channels. New voltage -controlled varactor UHF tuner
and a newly designed VHF tuner with MOSFET
contribute to better fringe -area reception and
increased sensitivity. A new angular tint control
for "normal" or "wide angle" color demodulation
minimizes tint and flesh tone change when you

switch channels or when programs change.

Other features include "instant on" with override; automatic fine tuning; adjustable tone control; stereo -hi -fi audio output; automatic chroma
control; adjustable video peaking; adjustable
noise limiting; gated AGC; illuminated channel
identification. For total armchair control, there's
even an optional wireless remote control. The
exclusive Heath MTX -5 ultra -rectangular bright
tube measures a full 25 inches diagonal, 315 sq.
in. viewing area has a specially etched face
plate to cut glare, with each color dot projected

against solid black background for extra crisp-

built-in dot generator and tilt -out convergence panel are periodic adjustment aids
you'll find only on Heathkit sets. And a built -in
volt -ohm meter and simplified troubleshooting
section in the manual permit self- servicing
should the need ever arise. The new Heathkit
catalog lists four beautiful cabinets for the
GR -900, plus the exciting new custom wall mount
that allows you to build the set into a wall.
Brighten your life with the Heathkit GR- 900...
ness. The

now! 125 lbs.

Kit 6D -348
Kit IT -121

49 95*

New Heathkit
IT -121 FET Tester
Tests transistors, diodes, FETs,
SCRs, triacs, unijunction transistors in or out of circuit. 5 current

ranges measure leakage as low as

1 uA and collector currents as
high as 1A. Gain (DC Beta), trans conductance (GM) and leakage
values read directly on large
meter face. Special battery testing circuit gives meter indication

of self- contained power supply.

6

lbs.

8995*

New Heathkit
Deluxe Metal Locator

New Heathkit CI -1040

Spots metal objects as small as

Inductive Timing Light

Features extra bright daylight use flash and all new triggering
method. Special low- voltage inductive trigger pickup coil lets
you connect light while engine is
running, eliminates direct connections to spark plug, prevents
interference with other test instruments connected to engine.
High- impact, shock-proof plastic
case. 4 lbs.

Lane; MASS.: Boston (Wellesley), 165 Worcester St.;

MICH.; Detroit, 18645 W. Eight Mile Rd. & 18149 E. Eight
Mile Rd.; MINN.: Minneapolis (Hopkins), 101 Shady Oak
Rd.; MO.: St. Louis, 9296 Gravois Ave.; N.J.: Fair Lawn,
35 -07 Broadway (Rte. 4); N.Y.: Buffalo (Amherst), 3476
Sheridan Dr.; New York City, 35 W. 45th St.; Jericho,
L.I., 15 Jericho Turnpike; Rochester, Long Ridge Plaza;
OHIO: Cincinnati (Woodlawn), 10133 Springfield Pike;
Cleveland, 5444 Pearl Rd.; PA.: Philadelphia, 6318 Roosevelt Blvd.; Pittsburgh, 3482 Wm. Penn Hwy.; TEXAS:
Dallas, 2715 Ross Ave.; Houston, 3705 Westheimer;
WASH.: Seattle, 221 Third Ave.; WIS.: Milwaukee, 5215
Fond du Lac.
Circle 100 on

dime underground, searches

under water up to 2 ft. deep. Unit

sounds off only when metal is
neared, tone gets louder as you
approach. Convenient grip- mounted controls. Handle telescopes,
head swivels to fold into neat flat
package for carrying in optional
leather carrying case with shoulder
strap (6.95 *). Headphones (4.50 *)
and battery (1.50 *) are optional.
Order your GD -348 today. 6 lbs.

HEATHKIT
20-11
Benton Harbor, Michigan 49022
Schlumberger
Please send FREE Heathkit Catalog.
Enclosed is $
plus shipping
Please send model(s)

HEATH COMPANY, Dept.

0
0

Name

Address
Zip
City
State
Prices & specifications subject to change without notice.
*Mail order prices; F.O.B. factory.
CL-440

readerservice carT
NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

77

READER QUESTIONS

(continued from page 72)

out." Then, very slowly, bring it back

until you see a good color picture. Going just a little too far will cause this
color condition, before you black out
the whole picture. Get it set exactly
right, and it will hold.
S- BENDING
very bad case of bends in the
picture, with sync instability, etc., in a GE
AA chassis. I have checked all of the filter
capacitors, with no results. What is caus-

I have a

ing

this?- C.L.E., Malacanang, Philip-

pines

Telex headphones and headsets give you that comfortable feeling

of assurance when you monitor broadcasts or communications.
Signals come through loud and clear
intelligibly and reliably.

Telex professional monaural or stereo headphones incorporate

audiometric -type transducers that are impervious to temperature
or humidity changes and provide you with absolute performance
consistency day in, day out. These sensitive dynamic transducers
produce high output levels with minimum consumption of transmission power. Available in single or dual muff configuration and
with noise cancelling dynamic or carbon boom microphones.
And you'll never miss a cue or program buss with a Telex
Anouncers Earset . Inconspicuous for `on camera' work, it has
practically become standard in the industry.
Or you can select a Teleset , Twinset or Earset for lightweight, comfortable and inexpensive private monitoring. And for
special applications in business or home, industry or institution,
Telex makes a listening device to fit your requirements. Available
at better sound dealers or write for free information. You'll hear
more from Telex.
PRODUCTS OF FOUND RESEARCH.

17)
COMMUNICATIONS

DIVISION

9600 ALDRICH AVENUE SOUTH

MINNEAPOLIS, MINNESOTA 55420

This chassis has two main PC

boards, mounted to a sheet -metal frame
with self-tapping screws. If either of
these boards develops a high- resistance
ground connection, you'll get symptoms
exactly like this.
Suggestion: loosen and retighten
all of the grounding screws. If this
doesn't help, then run extra grounding
wires, or shield- braid, between the
ground foils and the chassis. Most likely
suspect, the one with the video if., agc
and so on.
INTERMITTENT FLARE, RASTER
COLLAPSE
In a Clairtone C11 color TV chassis,
the picture bloomed brightened showed
retrace lines, then faded and went out, at
intervals. I replaced the 3A 3, and it
cleared up for about 10 minutes, then went
out again. Pulled chassis, took to shop. As
expected it played for hours! -S.J., Scarborough, Ont.
(I started to answer this, then got
another letter! In this, the reader said
"Never overlook the too -simple and obvious things! While waiting for the
thing to cut out, I pushed down on one
corner of the PC board, and the raster
flared and went out. So did the heater of
the G -Y amplifier, the R -Y /B -Y amplifier and the X demodulator. Common
ground point for these heaters is an eyelet on the corner of the PC board. Now
everything is fine.)
That's what I like; self-answering
questions! Thanks to Steve Jordan,

Scarborough, Ontario, Canada.

HOT POWER TRANSFORMER
One of my customers replaced the
EZ81 rectifier tube in his Eico HF-12
amplifier with a 6CA 4. He said it played
well for about an hour, then the power
transformer burned out! I replaced the
power transformer with an exact duplicate, but it runs hot!
I have checked the current drain, and
it runs only about 60 mA instead of the 90
mA specified Dc voltage is + 360 V, as
shown, but the transformer still runs very
hot. What do you think ? -B.A. Houston,
CANADA: DOUBLE DIAMOND ELECTRONICS, LTD., Ontario
EUROPE: ROYAL SOUND COMPANY, INC., 409 North Main Street, Freeport, N.Y. 11520 U.S.A.
Circle 19 on reader service card

78

RADIO -ELECTRONICS

NOVEMBER 1972

www.americanradiohistory.com

Tex.

Power transformers are heated by

Speaker super market?

Super speaker market.

In a super market,
you get a big selection,
low prices, nationally - adver-i ed
merchandise. Make Quam your s?eaker
super market.

Write for a ccpr of

our super new

Pick the size, power handling capacity,

and price you need to match the function:
public address, background music, intercom,
outdoor, or whatever. We have 60,000 speakers,
135 different models, ready to transfer from
our shelf to your wagon.

Catalog 72

What makes a super speaker market? Super

performance speakers. That s Quam, too.
We use only top grade materials, stringent
quality control, and advanced manufacturing
methods to make sure our speakers work the way
your customer expects them to.

Quam: ed

Quarr Nichols Company

Chicago, Illinois 60637
Phone: (312) 488 -5800

Decision

Circle 20 on reader service card

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

79

power. Power is "EI" which is voltage

multiplied by current. So if your transformer has normal voltage and slightly
less than normal current, your load circuits are not taking too much! If the
transformer overheats, it may be the
wrong transformer for this amplifier or
it may even have a shorted turn in one
of the windings. Check the transformer
by pulling the rectifier tube, and disconnecting the hot wire to the heaters.
In other words, take off all loads.
Now plug it into a wattmeter. Normal reading should be almost zero. All
you should see is the iron-loss which
will be below 5 watts. If the transformer
has an internal short, you will read 25-

35 watts or more. If it shows no

internal
short, but still gets too hot, it may be
that it doesn't have the right current -rating.

No wattmeter? Hook a 1 -ohm

wirewound resistor in the primary; read
ac voltage across it. 1.0 volt equals 1.0
ac ampere.
A transformer is "too hot" when it
melts the wax, smells, etc. It may run
too hot to hold your hand on, but if it
doesn't stink or smoke -it may be OK!
INTERMITTENT TRANSISTOR
In one of your articles, you said that
transistors will not become intermittent.
Not too long ago, I got a call on a Syl-

TV TUNER SERVICE

vania D -14 color chassis. After a lot of

trouble, Ifound that the video output transistor was intermittent! I could move the
collector lead and make it cut out, either
in the circuit or on my transistor checker.
Replaced it, and the set worked Any comment? -G. W., Ipswich Mass.
Nope! Not too long after I did that
article, I, too, found one! Same type as
this, but used in an audio amplifier.
Collector lead intermittent there, too.
So I quit saying that you can't find intermittent transistors! Since then, I've

heard of others.
Seems to be mostly this type of
transistor; the little flat ones with 3 legs,
bolted to the chassis, heat -sink etc.
These are in "case -77" type cases. So
far, none of the other cases have shown
intermittents, but I'm waiting; and not
sticking my neck out.
VERTICAL PROBLEMS

VHF, UHF, FM or IF-Subchassis...

...

All Makes

gollgr..
fiase 81serce!

I've got all kinds of vertical problems

in a Zenith 14N22 chassis Can't get
enough height with the proper linearity,
the sync is bad and you name it I've got
iL I've checked all of the coupling capacitors for leakage, and the resistors read
within tolerance.-L.C., Ink, Ark.
Y'missed one! Check the little PC
integrator unit in the feedback loop,
from output plate to "input grid "; PC -2
on the Sams schematic. You'll probably
r68K

it to yourself

You owe

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Box 3189-Springfield, Mass. 01103
Box 7332 -Longview, Tex. 75601
Box 4145 -Denver, Colo. 80204

RADIO -ELECTRONICS

Zenith part number is 87 -7, and I

think it can be replaced by a Centralab
PC -90, etc. The diagram shows the
equivalent circuit; if you have to, you
can make up one of these from separate
parts.
VERTICAL LINEARITY PROBLEMS
I had an Admiral HIA 1 chassis, with
a "no high voltage problem. " Bad horizontal yoke coiL Since I happened to have
a universal-type yoke that I picked up
somewhere on hand I tried ix Now I get
high voltage, but the vertical linearity is
pretty bad Can't correct it with the controls.

PTS ELECTRONICS, INC.

HOME

find that this thing is open. You should

be able to read about 150,000 ohms
from end to end, and about .001 -F of
capacitance from either end lead to the
center (ground) lead.

Tel.
Tel.
Tel.
Tel.
Tel.
Tel.

812/824 -9331
904/389 -9952
916/482 -6220
413/734-2737
214/753 -4334
303/244.2818

Circle 21 on reader service card

NOVEMBER 1972

www.americanradiohistory.com

This yoke, by the way had a label

"DY-57A T" on it. Do you think this is a
mismatch problem? -C.P., Stow, Mass.
I'm afraid I do! If your universal
yoke is a Stancor DY -57, as it seems to

be, it'll have a vertical winding of about

70 mH. The correct replacement yoke
for this Admiral chassis should be about
13 mH. You can get by with about a
20% mismatch in a lot of sets, but this is

completely out of the ball-park.

Evidently your horizontal winding
is close enough, but I'm afraid that
you'll have to get a yoke that will be
closer on the vertical.
HORIZONTAL OUTPUT
TRANSISTORS?
The horizontal output transistors and
the flyback have burned out on a Sony 9304UW TV set. They use two 2SC41
transistors in parallel Can't find a replacement for these. Any ideas? -W.J.
McL., Phoenix, Ariz.
You might be able to replace these
two with a single transistor with the
proper ratings. For example, a Sylvania
ECG -163, which is an npn, silicon, with
a 700 -volt breakdown voltage, and a
rating of a whooping 100 watts peak.
There are other similar types available.
For luck, run the ac line voltage up
slowly with a Variac, watching the collector current, and output, etc. as you
go. Normal current here is given as 520
mA per transistor. If the thing doesn't
get too hot, fine.
(Note: we got some "field feedback" from the reader on this. He tried
the single transistor, and it worked. Got
pretty warm, but worked. Just for luck,
he replaced the surviving 2SC41 in parallel with it (one of them turned out to
be good!) whereupon both transistors
cooled off, drew about 360 mA. apiece,
and everything worked very nicely!
Thanks to W.J. McLain, of Phoenix, for
this one.)
BAND OF RIPPLES
I've got some of the most weird
symptoms I've ever seen in this Motorola
Quasar II TS-929 chassis. With a picture,
there's a vertical "band of ripples" right in
the middle of the screen, flickering with
all colors! If I take the antenna off I get
very thick black vertical bars, odd shaped
like Barkhausen, but definitely not;
they're all over the screen! I scoped the
horizontal sync, and the sync pulse goes
all to pieces when the antenna is disconnected -R. T., Hatfield Ark.
I've seen this before. Uncommon,
but it happens. Look for a very small if
choke, encapsulated, mounted on the

plate -cap of the 6LF6 horizontal output

tube. Take a piece of wire and short this
choke! This will clear it up.
Apparently, this choke causes the
horizontal output stage to ring heavily
at some high frequency, and generate
parasitic oscillations. Shunt it, and they
quit! (Usually, the if choke in the horizontal output plate lead suppresses
spurious oscillations. However, in this
case, it appears that the choke can cause
hf or vhf oscillations.)
R-E

Perma -Power Color Brite

when the picture looks good,

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When a color TV picture fades, or when the black- and -white is erased by a
cathode -to- filament short, you can save the day, and the tube, by installing a
Perma -Power Britener.

Boost models bring out lost sharpness

and detail by providing increased filament voltage to increase electron
emission. Full contrast and color quality return immediately.
Isolation models restore the black and -white information that gives a
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Short now
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both jobs with a Color -Brite Combination Isolation and Boost Britener.
There are Perma -Power Color Brite
models for both round tubes and rectangular tubes. In fact, Perma -Power
has a Britener for just about every picture tube ever made! You'll look very
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tube. Pick up a supply of Color - Brites
from your Perma-Power distributor!

PERMA -POWER DIVISION

CHAMBERLAIN MANUFACTURING CORPORATION
5740 North Tripp, Chicago, Illinois 60646
Circle 22 on reader service card

birth defects
are forever.
g1Ve to

thHPACmatch UBSERVICE !TNBLI

NOVEMBER 1972

www.americanradiohistory.com

RADIO- ELECTRONICS

81

new products
More information on new products is available from the
manufacturers of items identified by a Reader Service number. Use the Reader Service Card inside the back cover.
LAB SCOPE, model KC -6060A combines
a 1 -kHz sinewave oscillator (with variable
output level from zero to 1 V rms, regulated by front panel volume control) and a
3 -inch oscilloscope (for waveform displays up to 200 kHz). Has 5- position selector to test 0.1 V peak -to -peak to compare voltage measurement of an input
signal against a 1 kHz sine waveform;
waveform left for left channel audio signal;
waveform right for right channel audio sig-

nsec rise and fall time. Output 50 ohms; instrument is short- circuit proof. $159. (assembled $220). -Dytech Corp., 391 Mathew St., Santa Clara, Calif. 95050.
Circle 32 on reader service card

INTRUSION DETECTOR, Sound Discriminator. A series of intrustion alarms

that operate with ordinary paging speakers as microphones. Can also be used
with other sensors or switches. Discriminates against and rejects sounds for
which a response is not desired. Model
SD400AG, illustrated, has manual adjust-

A 32 -page booklet -almost a simplified

course in sound measurement- accompanies
each
instrument.
$75.RCA /Electronic Components, 415 South
Fifth St., Harrison, NJ 07029

nal; stereo display with left channel signal

applyed to vertical section, right channel
signal to horizontal section; FM multipath
to check performance of a tuner or adjust
antenna. Can be used to check an amplifier for linearity, frequency response and
phase characteristics; measure phase difference between two signals; test phono
cartridges and more. $224.95. -Kenwood,
Dept. P, 15777 So. Broadway, Gardena,
Calif. 90248.
Circle 31 on reader service card
PULSE GENERATOR KIT, model 701. A
professional type instrument with all -integrated design, sockets for all integrated
circuits and protected outputs. Pulse repetition rate: 10 Hz to 10 MHz in seven
overlapping ranges; output pulse amplitude 0 to 5 volts across 50 ohms -0 to 10

Circle 34 on reader service card

BURGLAR ALARM SYSTEM, RA -IV. Completely self- contained wireless system operates on 117 -volt ac or on its own dc supply should power fail. One central
receiving station receives from any number of small wireless transmitters within
250 -foot range. Transmitters use re-

ment of reference ambient level and manual selection of number of events (2 to 5)

to be received in an accumulation time period, to reject occasional and non- repetitive loud sounds. Units are available for 10
inputs up to 120 inputs. -Scientific Security Systems, Inc., Jackson, Miss. 39216.
Circle 33 on reader service card

NOISE POLLUTION MONITOR, RCA WE130. A hand -held, battery -operated unit for
measuring sound levels in factories, airports, urban traffic areas and other high noise areas.
The WE -130 uses solid -state circuitry
and is powered by four penlight cells.
Weight is a little over 11 ounces. Dimensions are 6'/a x 3 x 1 15/16 inches. The
meter scale is divided into three parts. The
green portion is the safe area; the yellow
indicates levels bordering on the unsafe.
Readings in the red indicate noise that
can be dangerous to hearing if maintained
for long periods.
.

volts unterminated. Pulse width: 50 nsec

to 100 msec, in seven overlapping ranges.
Duty factor: 90% at all frequencies. Rise
and fall time is less than 5 nsec, jitter less
than 0.1 %, baseline offset 0 volts for both
trigger and pulse outputs. Oscilloscope
trigger output, 1.2 -volt, 50 nsec width, 10

82

RADIO -ELECTRONICS

NOVEMBER 1972

www.americanradiohistory.com

chargeable batteries that are good for six

months normal operation, and can be recharged with unit that forms part of receiver.
Alarm is a loud pulsating siren. $159. (for receiver and one transmitter). -Lumik, P.O.
Box 1312, Douglas, Ariz. 85607.
Circle 35 on reader service card
AIR ACTUATED SWITCH, 74 Air Wave
Switch. Performs many alarm, detection or

control functions cheaply where relatively

expensive floor mats, motion detectors or
light beams are often used. Typical application uses 100 feet of '/a -inch inside diameter plastic tubing, which can be zig-

zagged under a carpet or mat or run

through grass near a fence. A footfall on
the tubing generates an air wave that actuates the switch. Contacts rated at 1A,

microwave uhf Doppler radar system. Protection is provided over as much as 3500
square feet or a 30-foot radius. Microwave
transmissions penetrate most non- metallic
structures and are reflected by metal.
Movements from an intruder set off the
alarm circuits, while a digital filter rejects
movements of small animals and other
false alarms. Powered by 117 Vac or optional 12 Vdc battery. Measures 33/4" x 6"
x 7 ", weighs 4 lbs. $185.- Mountain West
Alarm, 4215 N. 16th St., Phoenix, Ariz.

external gain control affording a gain reduction range of more than 40 dB independent of receiver agc. $31.95. -Castle
TV Tuner Service, Inc., 5710 N. Western
Ave., Chicago, Ill. 60645.
Circle 39 on reader service card
LOW -COST CITIZENS BAND RADIO Pace
223. An all U.S. made two -way unit that
provides all 23 channels of operation

through a crystal synthesizing technique

that compensates for temperature drift.

85016.
Circle 38 on reader service card

TV TUNER SUBBER Mark It Improved

version has higher gain and longer battery
life. Uses LED indicator. Substitutes the
vhf tuner in defective TV receiver to prove
if original tuner is good or bad. Simplifies

330V (ac). Switches cost less than $15.Mountain West Alarm Supply Co., 4215
North 16th St., Phoenix, Ariz. 85016.
Circle 36 on reader service card

SCANNING MONITOR, SCAN 308. A programmable 3 -band scanning monitor receiver covering 25 -50 MHz, 140-174 MHz
and 450 -470 MHz simultaneously. Can be
programmed easily to monitor any combination of eight channels in the high -band
vhf, low -band vhf or uhf ranges. Visual
M

analyzing i.f. and agc system defects and

tests the uhf tuner. Only two connections
must be made, antenna and i.f. cable. Set
of i.f. extension cables is furnished. Solid state tester is battery powered. The portable unit uses a transistor vhf tuner with

Reliable in sub -zero temperatures as well

as hot desert climates. Full squelch control with 0.3 V threshold. Agc circuit
holds volume essentially constant over a
signal range of 0.5 IN to 100,000 V (0.1
volt). Input power of 5 watts, with modulation boost circuit for maximum talk level
performance within the class -D Citizens
Band Radio regulations. U.S. made design
includes use of U.S. made transistors and
components, facilitating in -field servicing.

Pix- Mato
the

TM

cri tester

von can afford to take aluno

readout. Rear

panel

programming

switches select the desired combination

from the units total capacity of 16 channels. Built for both ac and mobile 12 -volt
use. $189.95. -Pace, Box 306, Harbor
City, Calif. 90710.
Circle 37 on reader service card
MICROWAVE INTRUSION DETECTOR,
model A5 -001 Space Switch, provides total premise protection by giving an alarm

onlv ... '34.95

quality CRT tester with

individual test for each gun.
Compare guns for emission.
Test for leakage and shorts.
Legible 3 color scale.

Compact, portable, rugged.

Avoid recalls, check the CRT
on every

call.

take alone the time savers

WRITE US!

triggered by forced entry through roof,

wall, door or window. Unit is all solid -state

ere

.t
Circle

61 on

PIX -MATE
CRYS-MATE GEN -MATE
SOUND-MATE TRACE-MATE

The Caddy -Mate

reader service card

NOVEMBER 1972

www.americanradiohistory.com

line.

2245 PITKIN AVE., BROOKLYN, N. Y. 11207

RADIO -ELECTRONICS

83

Now...the most enjoyable,

do-it- yourself project
of your life -a Schober

$109.95. -Pace Communications Div.,

Pathcom, Inc., P.O. Box 306, Harbor City,
Calif. 90710
Circle 40 on reader service card
4- CHANNEL SYNTHESIZER, derives two

additional channels from existing two channel stereo material. Makes use of differential phase relationships of the two
signals. The unit provides an easy, in-

Electronic Organ!

range 130 dB. FET amplifier is built into

microphone body. Prices: PAC -1, $79.50;
PAC-2, $139.50; PDC -1 (less battery),
$49.50; PDC -2 (less battery), $99.50.
Electronic Enterprises, 3305 Pestana
Way, Livermore, Calif. 94550.
Circle 42 on reader service card

You'll never reap greater reward,

more fun and proud accomplishment,
more benefit for the whole family, than
by assembling your own Schober
Electronic Organ.
You need no knowledge of electronics, woodwork or music. Schober's
complete kits and crystal -clear inwhoever you
structions show you
are, whatever your skill (or lack of it)
how to turn the hundreds of quality
parts into one of the world's most
beautiful, most musical organs, worth
up to twice the cost of the kit.

expensive way to sample 4- channel sound

using two- channel stereo equipment. Basic model, $6.95; with volume and balance
controls, $9.95.- Robins Industries Corp.,
75 Austin Blvd., Commack, N.Y. 11725.

unique tools,
handy

20th year of service to the World's

finest craftsmen and technicians.

j\

Send

Schober color catalog, with all the

fascinating details!

a FREE

ADDRESS

name

I address

city
A

STATF

copy of the nc Flasher

1

I state

NAME
CITY

National Camera

V2000 West Union Are. Dept.GB8

En lewood, Colorodo, SOI10

Get the full story FREE by mailing

Yolsoie4 Organ Corp., Dept. RE -108

West 61st Street, New York, N. Y. 10023
Please send me Schober Organ Catalog.
Enclosed please find $1.00 for 12 -inch L.P.
record of Schober Organ music.
71P

zip

Nationa Camera
V2000 West Union Are. Dept. GIB

En lewood, Colorado, 80110

Circle 63 on reader service card
.

84

Circle 62 on reader service card

RADIO -ELECTRONICS

ELECTRONIC IGNITION SYSTEM, Capacitive- discharge kit, claimed to develop

50% more spark energy for complete combustion and increase spark magnitude to

Our

the coupon TODAY for the big

43

Circle 43 on reader service card

kits,

precision
instruments,
technical
supplies.

sets, chimes, and more.

The

CALCU-

ohms. Can also be used as an automatic

voltage divider with up to 25 different divisions. $17.45. -Lee Electronic Labs, Inc.,
88 Evans St., Watertown, Mass. 02172.

1000

assembling, then learning to play the

modern King of Instruments through
our superlative instructions and playing courses.

RESISTANCE

LATOR, model R -1, makes available over

825 different values. The unit is a 10% step
decade that covers 100 ohms to 11 meg-

CONDENSER MICROPHONE KITS, PAC 1 and 2. PAC -1 is a kit for single microphone, with power supply; PAC -2 a two microphone kit with dual power supply for
117 -volt operation. PDC -1 and 2 are the

Five superb models with kit prices

from $500 to around $2,000, each an
authentic musical instrument actually
superior to most you see in stores,
easy for any musically minded adult
to learn to play, yet completely satisfying for the accomplished professional. And there are accessories you
can add any time after your organ is
finished
lifelike big auditorium reverberation, automatic rhythm, pre-

Join the thousands of Schober

Organ builder -owners who live in
every state of the Union. Often starting without technical or music skills,
they have the time of their lives -first

MINIATURE

Circle 41 on reader service card

equivalents for portable dc power supply.

Microphone frequency response 50 Hz to
15 kHz, 5 dB; signal /noise ratio 50 dB;
sensitivity -66 dB; cross talk less than 50
dB (based on PAC -2); output impedance
250 ohms unbalanced; maximum dynamic

NOVEMBER 1972

www.americanradiohistory.com

3-5 times normal for faster acceleration

and quicker starts, even in sub -zero
weather. Unit can be used with any 4, 6, or
8- cylinder engine having a 12V negative-

ground electrical system. Measures 3" x

5" x 31/2". $39.95. -Radio Shack, 2617 W.
7th St., Ft. Worth, Tex. 76107.
Circle 44 on reader service card
SIREN VEHICLE ALARM, model DU -272.
When armed, the dual -purpose lock does
not allow the ignition to be started. Should
an intruder attempt to open any of the
doors, hood or trunk, the siren sounds and

resets the unit. Speaker Guard is available

150/250 ohms. Flat response provides

faithful reproduction of drums, acoustic
guitars and other musical instruments requiring exacting sound fidelity. Pickup
pattern is also excellent for group vocal
work on stage or in the studio. Pop and
wind blast filtering precludes the need for
a wind screen outdoors. Also available in
a high impedance, model 655AH. -ling
Altec, Inc., 1515 So. Manchester Ave.,
Anaheim, Calif. 92803.

in 18 different models with varying combina-

tions of wattage and resistance -Workman

Circle 47 on reader service card

SPEAKER GUARD, consists of a resistor

and circuit breaker that can be easily connected in series with the speaker. A wattage
overload from the amplifier output activates
the circuit breaker and prevents damage to
the speaker. Resetting the circuit breaker

Electronic Products Inc., Box 3828, Sarasota, Fla. 33578.

R -E
Circle 48 on reader service card

RCA CONSUMER ELECTRONICS

SERVICE DATA SUBSCRIPTIONS

continues to sound until it is turned off by
the owner with a special alarm key. -On
Guard Corp. of America, 350 Gotham

RCA

Parkway, Carlstadt, NJ 07072.

Circle 45 on reader service card

RCA

RCA

CURRENT -LEAKAGE ADAPTER,

model 60 -407, measures leakage current
of 2 -wire and 3 -wire appliances, small portable power tools, speed controls, motors
and other electrically operated devices.
Tester is used with Triplett's Model 601
AC

RC/1

RCA
Plain Talk

Rcn

RC/1
.

CPIOA`'s

Serwce
Data
Cors'Np r
Eteclrorw,
Proo,cts

SEqVIT
`t
GOM2PLETE

Ftt.E yEAP

`$1

TV

35;

PHONOGPAPH

\1,5a

APOPECOP
t

A SUBSCRIPTION INCLUDES A COMPLETE "FILE" YEAR OF:

"GOLDENROD" BULLETINS
COLOR TELEVISION DATA
PARTS TIPS
B & W TELEVISION DATA
SERVICE TIPS
RADIO DATA
"PLAIN TALK" PERIODICALS
PHONOGRAPH DATA
TAPE RECORDER DATA
COMPLETE INDEX

FET vom. Ac leakage currents that can be

measured are 0 to .01- .03- .1- .3-10- 30-100
mA. Resolution is 0.2 pA on the 0-.01 mA
range. Accuracy is 4% full scale. -Triplett
Corp., Bluffton, Ohio 45817.
Circle 46 on reader service card

MICROPHONE,
OMNIDIRECTIONAL
Model 655AL. is designed to accurately
reproduce instruments in a live performance. Has a frequency response of 50 to
15,000 Hz and an output impedance of

25i

ILABLitE

"File- 1972"
"File- 1972"

Service Data including 2 binders S19.95

Service Data subscription $14.95
(Binders available separately -$2.95 each)
Previous years Data ($12.50 per set) File: 711i, 70:1, 6917, 68

Amount enclosed:

NAME
(Please Prrntl

STREET ADDRESS

CITY

STATE

ZIP CODE

Your order will be processed promptly upon receipt of your check

or money order in the amount indicated above
SEND TO: RCA CONSUMER ELECTRONICS
600 N. Sherman Drive, Indianapolis, Ind. 46201
ATTN: Technical Publications, 8-106 (Or Contact Your Distributor)
Note

Prices Subject To Change Wrthout Notice

Postpa,d U.S.A. only

Circle 64 on reader service card

RADIO -ELECTRONICS
NOVEMBER 1972

www.americanradiohistory.com

85

Tih7ETER .

Attention

"

r,me Ae A Glance
DIGITAL CLOCKS

:6:

Electronic
Technicians!

new lit

nce 1035

SCHOOLING
All booklets, catalogs, charts,

EXCELLENCE

in ELECTRONICS

data sheets and other literature listed here with a Reader

ENGINEERING
If you have adequate schooling and experience at the technician level you may be
able to qualify to enter our college -level
Home Study Program in Electronics Engineering. The CIEE Porgram is OUTSTANDING, and up -to -date in every respect. CIEE
is a forward -looking school, and Engineering is taught on the basis of application and
understanding rather than on the basis of
memorization. All lesson material and texts

DIGITAL
CLOCK MOVEMENTS
#130. .12

#75

Digital
Computer
Completa Line of Count -Up and
Count -Dawn Digital Computers

rs /ineerin(j

CATALOG ON REQUEST

Raymond Road

0.

PENNWOOD NUMECHRON CO.

Boo 10634

Established 1945
Formerly Cook's School of Electronics

MUTER ELECTRONICS
DIVISION Of LCA CORPORATION
7249 fRANKSIOWN AVE PITTSBURGH, PA. 15208

Circle 65 on reader service card

Circle 66 on reader service card

Jackson, Miss. 39209

THINK OF IT

ASACHEMICAL
ULTRASONIC BATH
r

Z+rir64+i

sfP'Rti Ah

IT

' t ...- ..

TV /FM ANTENNA INSTALLATION GUIDE, 10

page booklet covers antenna selection, masts,
mounts, lead -in wire, lightning protection and
multi -set systems. Illustrated with a series of
complete pictures and diagrams, the guide
gives the reader step-by -step instructions on
various types of home antenna installations. The
guide also gives a clear explanation on how to
protect the installation from wind and weather,
how to prevent damage to the roof and the
house and how to make the installation as solid
as possible. -Jerrold Electronics Corp., 401
Walnut St., Philadelphia, PA 19105.
Circle 50 on reader service card

PHYSICS 8 ELECTRONICS CATALOG, 10

pages of classroom demonstrators and potential
science fair projects. Includes such things as a
parametric ac motor, oscillating magnet, motion
detector demonstrator, perpetuum Mobile and
many other items of interest. -Sercolab, P.O.
Box 78, Arlington, MA 02174.
Circle 51 on reader service card

SILICON RECTIFIER CATALOG, six pages detailing this manufacturer's entire line of standard and fast -recovery silicon rectifiers. The
new catalog devotes individual pages to ratings
and electrical characteristics as well as dimensional drawings of case styles for EDI bridges,
high voltage axial lead rectifier cartridges, high
voltage rectifier assemblies and miniature axial
lead rectifiers -EDI, 21 Gray Oaks Avenue, Yon-

way you service tuners and other greasy

chassis troublespots. You'll save time, as a

kers, NY 10710.

concentrated power spray dissolves and

washes away dirt and gunk. You'll save money
-less spray is needed because there's a higher
percentage of active ingredients. And you'll do a
more thorough job-thanks to a premium formula
that's more efficient and won't damage components.
Next time you service, service chemically with the
world's best- selling degrecser- TUN -O-WASH #2400.
One of the fine chemical tools from
CHEMTRONICS INC.
1260 RALPH AVENUE
BROOKLYN, N.Y.11236

Our business is improving yours.

RADIO -ELECTRONICS

ELECTRONIC PARTS & EQUIPMENT CATALOG, 48 pages packed with all kinds of useful
electronic devices. Included are such things as
picture tubes, vacuum tubes, hi -fi components,
tools, rectifiers, books and test equipment -Cornell Electronics Company, 4217 University
Ave., San Diego, CA 92105.
Circle 49 on reader service card

Write direct to the manufacturers for information on items listed below:

The moment you do, you'll improve the

86

Ut

Tymeter
Elapsed
Time

COOK'S INSTITUTE
P.

HOUR

DIGITS .RESETTAEIE INDIVIDUALLY

Available in 5C, 60 cr., oli ooltooes, AC.
approved motor, cord. One Year Guarantee.

are thorough and easy -to- understand.

Through this Highly Effective Home Study
Program in Electronics Engineering you can
raise your status and pay to the Engineering
level. No residence classes required for
those who qualify. If you are an electronics
technician with above -average ambition, and
not willing to settle for anything less than
the best home study Engineering Schooling
available anywhere, then you should write
TODAY for our free revealing descriptive
literature. There is no obligation, and no
salesman will call on you.

0/ /'cfronic3

#131. .24

HOUR

Service number are free. Use

the Reader Service Card inside the back cover.

Circle 67 on reader service card

NOVEMBER 1972

www.americanradiohistory.com

R-E

GIVE...
wau

HEART
FUND

live

Unbeatable values from Supersonic!

EQUIPMENT REPORT
(continued from page 26)

FREE!

the positive (upward) or negative

(downward) slope of a waveform. The
fourth is the triggering ALTO -NORM
switch. In the AUTO position, the ac /dc
triggering switch and the trigger level
control are disabled. This position is
useful for signals which are too weak to
trigger the sweep circuits in the normal
fashion or for triggering simple waveforms. The NORM position of the switch
is used for other signals and, particularly, for low -frequency signals.
Construction of this oscilloscope is
not a simple project. The 10 -105 packs
an awful lot of circuitry into a compact
case. Six printed circuit boards are used
(the two vertical amplifier boards are
identical). Instructions are straightforward and, in the usual Heath fash-

8 -track car players

with every order.

su erbly engineered -all solid

state!

quence.
Because of the complexity of the
instrument's circuitry, calibration is necessarily much more time -consuming
than with a simple scope. However, the
calibration instructions are straightforward and easy to follow. Two procedures are given, one for calibration
without a calibrated generator and the
other with generator.
One of the great joys of this instrument is the stability of the calibration and balancing adjustments. After
using the instrument for several weeks,
a spot check was made of many of the
adjustments to see if they had drifted
away from their original settings. They
had not. One of the reasons for this stability is undoubtedly the extensive use
of voltage -regulated circuits in the
power supply. Many Zener diodes are
used. In addition, because of the solid state circuitry, the high temperatures of
tube -type equipment, with all their bad
effects on stability of calibration adjustments, are eliminated. All in all, this is a
superb instrument. Price of the kit is
$399.95.
A high- impedance, low- capacitance isolating probe is available as an
accessory for examining high- frequency
waveforms without distorting them or
loading the circuit being tested. This
probe is sold only as a wired unit at

R-E

(Reg. $6.00)

CONNECTS EASILY INTO YOUR CAR STEREO SPEAKERS

... -C-) -)-*

Model CXC -771 "Mecca" 18 watt car stereo mini 8 -track

cartridge player. Fits in any glove compartment. $27.95

Model CXC -772 "Grana:.a" 8 -(rack player

Easy wheel -type volume, tore & baian :.e
control. Powerful 20 watt arnowier for g-eat
stereo music in your car $29.95

Model CXC -773 "Mecca" 8 -track car player & FM multiplex

radio. Fantastic 20 ws!t e' ei send. One touch cnanues FM
to tape or multiplex to mr. naural, lighted r! al. stereo light
indicator. Sleek chrome & ble k st. ,nrJ ta2.95
Model CXC -774 same as above with FM & AM $69.95

'

ion, assembly follows a logical se-

$19.95.

8-track tape

of latest hits

All units with automatic

2

&

manual lighted push button channel changer.

hi- quality speakers for all above units $4.00. Easy installation instructions.

Supersonic Electronics Co.

in hopper

St. Dept.

A,

Brooklyn, N.Y. 11211

Circle 68 on reader service card

Sena check or money order.

Add postage Al: items fully
guaranteed. Free catalog.

GIVE... willve HEART FUND

Contributed by the Prbhthee

Lkiderma t
nds gmat.

You may have thought it was impossible to buy a good complete

magnetic stereo system for under $180. Now its possible. From
BSR. It's the BSR McDonald RTS -30. With an FM -AM receiver
that delivers 30 watts of clean music power. Included
are a pair of our SS -1 acoustically matched speakers
and our best selling 310 /X Total Turntable with base,
dust cover and Shure M -75 magnetic cartridge. Our
RTS -30. A magnetic system at a price you would pay McDONALD
for a ceramic. Even we're a little amazed.
BSR (USA) Limited, Blauvelt, N.Y. 10913

I'm interested. Send free catalog on all

your stereo systems and components.
Name
Address

Your lit le joke with the fake cord really

startled me, Mr. Conrad-almost as much
as this bill for the service call is going to
startle you.

Circle 69 on reader service card

NOVEMBER 1972
RADIO -ELECTRONICS

www.americanradiohistory.com

1
1
1
87

To Troubleshoot

FAST & EASY

use: Serviset

appliance clinic

Model EC

PATENTED

INSIDE THE CLOTHES DRYER

$ 3495tpaid

INFORMATION
COD
A precision engineered professional quality
electronic test instrument. Ideal for field or
bench servicing of all types of Communications gear.

CHECKS: sync, sweep, video, audio circuits,

high voltage supplies (DC, RF or Pulse), low
voltage supplies, coils, capacitors, resistors,
tubes, transistors, diodes, transformers,
speakers, etc. Will locate trouble to a particular otage, determine defective component
and can actually be clamped in circuit to restore circuit operation temporarily in 80%
of component or tube defects. Ideal for locat-

ing and confirming intermittents.

SPECIFICATIONS:

AF Signal Tracer, RF & AF Signal Injector, AC & DC Voltage Indicator 0/60/550/

20,000 DC Polarity Indicator 60/550/20,000
volts, Lo ohms 0 -5. Hi ohms 0- 500k -20 megohms. Tests Condensers, .00025 -12 mfd., Tests
Resistors 2 ohms -20 megohms, 2 Capacitance
Sub ranges .01 -.1 & 4 -40 mfd., 3 Resistance
Sub ranges 50 -500 ohms, 5k -25k, 100k-1 meg.
RF

&

NEW CT -1
From

Will allow you

to Dynamically test all
types of capacitors.

The Model CT-1 features a built -in electronic

power supply providing BOTH AC and DC
Test Voltages in a special circuit with high1y sensitive NEON type leakage indicator.
The CT -1 permits quick, accurate testing of
condensers for leakage or shorts with actual
DC voltage applied and readily indicates intermittent OPEN condensers with AC applied. Self-regulating power supply circuit
provides tapered forming current to suit particular requirements of capacitor under test.
Special circuit re -forms and polarizes electrolytic and tantalytic capacitors under test.
High sensitivity permits determination of
condenser dielectric breakdown before leakage causes major shut -down.

Only $16.95 postpaid

.00025 -1000 mfd.
Capacitor Range:
Over 200 M E G O H M S
Sensitivity:
80

DAY MONEY -BACK GUARANTEE

LEE ELECTRONIC LABS.. CO.

88 Evans Street
Watertown, Massachusetts 02172
Dealer inquires invited

649
88

by JACK DARR
SERVICE EDITOR

FREE

CLOTHES -DRYERS, LIKE MOST MAJOR

appliances, aren't really too complex.

They all have the same parts; a large
perforated drum, turned at a low -speed
by a motor; a heater and fan, to blow
hot air through the drum; a thermostat
to control the air temperature; and an
electrical driven timer to control the entire process.
In the electrically heated dryers,
large heating elements are mounted in
the air duct, with a fan to force the hot
air through the drum. The majority of
these use 240-volt heaters. Elements run
from 2,000 to 5,000 watts. The heating
elements have three controls; the switch
contacts in the timer, which will probably operate a relay to switch the high
currents, and a thermostat acting as a
limit switch. This breaks the heater circuit when the temperature rises above
the desired point.
So if the problem is "The drum
turns but the clothes stay cold." you
have one of four possibilities. Open
switch contacts in one of the three controls just mentioned, or an open heating
element. Many of the later model
dryers have multiple- section heaters, for
different heats. So, the chances of all of
these opening at once would be small. A
complete loss of heat would be most
likely to be in the three switches.
To check for this, pull the machine
out from the wall, pull the line plug and
take the back off. Usually this will be

fastened with self- tapping screws

around the edges. In a great many units,
you'll find a complete wiring diagram
pasted to the back or inside the cabinet.
With this, it isn't too hard to find the
wires going to the heaters and trace
them out. With a continuity meter, the
various switch contacts can be checked
by turning the timer knob manually to
the right position.
In the flat -top types, with controls
mounted on a splash -board (vertical
surface at the back of the top) many of
the controls will be quite accessible. In
several models, the whole top can be
slid back and lifted up, exposing all
heater wiring, controls, etc. A lot of the
wiring, including the timer, will use
push-on connectors, which makes it
very handy to check.

Circle 99 on reader service card

NOVEMBER 1972
RADIO -ELECTRONICS

www.americanradiohistory.com

The thermostat can be hard to get

to in some, especially if it is mounted

inside the air -ducts. However, you can

trace the wiring from the timer and controls, and locate the leads to it. Pull
these loose and you can check the contacts for continuity. If the dryer is cold,
the contacts should be closed, of course.
If you get an open -circuit reading across
the thermostat leads, its contacts aren't
making. Take it off and check the contact surfaces for burning or pitting. If
they are badly burnt, it would be best to
replace the thermostat. Filing down the
points would change the spacing, and
probably make the thermostat lose calibration. Be careful while handling
them, since calibration can also be upset
by bending the blade. Some units use a
"snap- action" thermostat, making use
of what is called the "oil -can effect ";
these are not easily upset.
If the drum won't turn, but you can
hear the motor running, you've got a
belt problem. This is accessible as soon
as you take the back off. If the belt has
jumped off, check the alignment of the
driving and drum -pulleys, and the motor mounts. Failure or breakage of one
of the motor mounts can throw the motor out of line and the belt will jump as
soon as it's started the next time.
If the belt is broken, take the old
one to an appliance supply house to be
sure you get the right length and size replacement belt.
Some units use a spring -loaded
idler arm. It moves to tighten the belt
and make the drum turn. Check the
control linkage, springs, and bearings
on this. The whole thing is usually easy
to get at, and adjustments are simple,
mechanical. If the idler arm doesn't
hold the belt against the pulleys tightly
enough, it will slip, causing rapid wear
and short belt life. With the arm engaged, the belt should have only a small
amount of slack.
The timers are driven by a small
electric motor, similar to electric clock
motors, mounted on the back of the
switching unit. In many makes, this motor can be replaced without changing
the whole timer. Two screws hold them
in place, on a bracket.
If the whole timer must be re-

placed. the push -on connectors make

this job a lot easier. Color- coding of
wires is used extensively, and the whole
thing should be shown on the wiring
diagram. If this isn't clear enough, or if
it doesn't show color- coding, make up
your own drawing of the wires.
The best way, if a timer must be replaced, is to leave the old one in place
until you have the replacement. Then,
unbolt the old one, and pull it away
from the panel, leaving the wires connected. Mount the new unit, and then
transfer the wires to it, one at a time.
Much less chance of confusion.
Fan /blower problems are usually
fairly obvious. If the fan doesn't run,
check the belt. Many of these are driven
from the drum motor; others have their
own small motor. Most of these are
mounted on some kind of shock mount- rubber pads. etc., to prevent excessive noise and vibration. If these
mounts have gone bad, from old age or
heat, the fan- blades can hit the sides of
the duct, making a terrible uproar. It's a
good idea to check all rubber mountings like this, whenever you have the
back off the dryer.
All in all, you shouldn't find any
really complex problems in modern
clothes dryers. Simple electrical equipment, such as a vom for checking continuity and ac voltage, will tell you what's
going on (or not going on, as the case
may be).
R -E

COMMANDER
COMMUNICATOR

SPEAKER
GUARD
YOUR

Pudgeettaa Tact

Your Pushbutton Valet will run your verbal

errands and find that hard -to- locate person.
With locking light and ringer, he remembers
your calls so that when you return to your
desk they may be answered. If you ask, he
jealously protects your privacy, or the flip
of a switch will give you hands -free reply to

Or with an optional handprotect the pri vacy of your incoming calls. With his magic
100 watt booster amplifier he can page over
100 loudspeakers atone time. Your Pushbutton Valet never tires and never wears out.
Where most intercoms hove maximum capacityat 12 or 24 switches, the Pushbutton Valet
can grow to 72 sw itches or even more on special order. With the Pushbutton Valet at your
indeed be called the Commander
side you w
Communicator. Write, wire or call

incoming

ca

set your Pushbutton Va let w

i l

l l

/f/etow- kittelfai .F,tAauee

PHONE

PHOENIX. ARIZONA

602.264 1346

65015

An overload in wattage of amplifier

output activates circuit breaker and
prevents damage.
Reset circuit
breaker and make sure you use correct values of Speaker Guard.

18

DIFFERENT VALUES

ASK FOR

Circle 70 on reader service card

CAT.:

145C

WORKMAN
Boo 3628 5

1646 WEST CAMPBELL AVE

Aa50r

Circle

r,

71 on

33,-

/U,C
PR00UCT5.INC

reader service card

Why pay an answering

service when you can
own your own?

A MIND IS
A TERRIBLE THING

i0 WASTE.

PROTECTS SPEAKER
AND AMPLIFIER

Air

A lot of the young people we help

would never get to college without
financial aid.
With your help, we can help
more of them. Please send a check.
Whatever you can afford. To 55
East 52nd Street, New York, N.Y.
10022.
We just can't afford to waste

anybody.

GIVE TO THE
UNITED NEGRO
COLLEGE FUND.

Dictaphone has a machine to

make sure you never lose another cent through a missed
phone call or a garbled message. In fact, we have a whole
line of them.
They're called Ansafones. You can buy one outright
or possibly lease it for about what you're paying your
answering service now. And it works for you 24 hours a
day, 7 days a week.
For a free brochure describing how much an
Ansafone can help you, mail this coupon now.

Dictaphone
Box

L- 1134, 120 Old Post Road, Rye, New York 10580

Please send me full details of the Ansafone line.

Name

' Company.

_Phone

I Address
City
advertising contributed for the public good

__

Zip Code

State

ICouNG`yr

Ilttt

Ansatone and Dictaphone are registered trademarks of Dictaphone Corp.

Circle

72 on

reader service card

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

89

ELECTRONIC
TECHNICIANS!

try this

MODERN CIRCUIT BOARDS

Raise your professional standing

and prepare for promotion! Win

your diploma in

ENGINEERING
MATHEMATICS
from the Indiana Home
Study Institute
We are proud to announce two great
new courses in Engineering Mathematics
for the electronic industry.
These unusual courses are the result of
many years of study and thought by the
President of Indiana Home Study, who
has personally lectured in the classroom
to thousands of men, from all walks of
life, on mathematics, and electrical and
electronic engineering.
You will have to see the lessons to appreciate them!
NOW you can master engineering

J9404

INTERCHANGEABLE PROBE TIPS

In a very short time, you can make
up a set of test probes with interchangeable tips that can save time when servicing printed circuits and wiring in miniature electronic assemblies. The basic
test prods are leads with banana jacks.

J9405

J9404, 32 late no. marked xistors, 4

TO -5 ICs, resistors, capacitors DIP
sockets etc.
STOCK NO. J9404
3.00 ea. 3/8.00
J9405, 23 marked xistors, 8 TO -5 ICs,
resistors, caps, DIP socket, LSI socket.
STOCK NO. J9405 2.50 ea. 3/7.00
ONE EACH J4904 & J4905
$5.00

TRANSFORMER SPECIAL
Ideal transformer for NIXIE tube circuits. 3 center tapped windings, 30
volts 1 amp., 16 volts 3 amps. and 150
volts 100 ma.
$3.00 ea.
STOCK NO. J9254

mathematics and actually enjoy doing it.

WE ARE THIS SURE: you sign no
contracts -you order your lessons on a
money-back guarantee.
In plain language, if you aren't satisfied you don't pay, and there are no
strings attached.
Write today for more information and
your outline of courses.
You have nothing to lose, and everything to gain!

COMPUTER GRADE CAPACITORS

(BRAND NEW)
Stk. No. F2026
Stk. No. F2118
Stk. No. F2117
Stk. No. F2116
items.
Send
new
Many other
for
48 page catalog
All merchandise guaranteed. Please include
sufficient postage, excess will be refunded.

40,000 mfd. 10 volts 1.26 ea. 6/7.00

70,000 mfd. 10 volts 1.76 ea. 6/9.00
6,000 mfd. 55 volta 1.50 ea. 7/9.00
3,750 mfd. 75 volts 1.75 ea. 6/9.00

The INDIANA
HOME STUDY INSTITUTE

DELTA ELECTRONICS CO.

Dept. RE -11, P.O. Box 1189, Panama City, Fla. 32401

BOX 1, LYNN, MASSACHUSETTS 01903

Phone (617) 388 -4705

Circle

73 on

reader service card

SILENCE

AO

.NGs

Circle

75 on

reader service card

NEW, FREE
FIRE /R l RGI,1 R

ALARM C

OR

TP

BANANA

LOG

64 pages presenting 350 intrusion

and fire alarm products for today's
skilled alarm installers and electronic
technicians. Includes the latest systems and detectors, hard -to -find
parts, accessories, and technical application notes on uses and circuit
designs.

PLUGS

AND

CLEAN

T00?
Then use Quietrole

... the

choice of

better servicemen everywhere for

cleaning and lubricating all T.V. moving parts.

Spray Pack guarantees silent, smooth
operation, with absolutely no harmful
aftereffects for both color, and black
and white sets.
Also available in bottles
If you prefer.

Product of

OUIETROLE
:

COMPANY

Spartanburg, South Carolina

90

PIN JACK

MINI CLIP

NEEDLE

The first test tip consists of a pin

jack back -to -back with a banana plug.
The jack end of this tip fits snugly over
test points and terminals in many receivers. The second and third tips consist of banana plugs backed -up by a
miniature alligator clip and a press -fit
R -E
needle -point. -Peter Legon

Circle 74 on reader service card

NOVEMBER 1972
RADIO -ELECTRONICS

www.americanradiohistory.com

/XX\ mountain west

W:1:rm

supply 4o.

4215 NORTH 16th S'T'REET

PHOENIX, ARIZONA 85016

Circle 76 on reader service card

Introducing
the expensive
dual-trace scope
that doesn't
cost a lot.

new books
ABC'S OF ELECTRONICS, by Earl J. Waters. Howard W. Sams 8, Co.,
Inc., 4300 W. 62nd St., Indianapolis, IN. 46268. 8%2 x 5% in. 160 pp. Soltcover, $3.95.
This latest edition is an easy to grasp, but comprehensive introduction
to the broad field of electronics. The author avoids complicated technical
concepts and mathematical terms as much as possible and relies on
simple language and on analogies familiar to everyone. The text presents
a detailed anlaysis of the principles of the principles of electricity, functions of atoms and electrons, magnetism and solid -state physics. Individual chapters are devoted to electrical resistance, capacitance and inductance. The remainder of the book deals with alternating currents, circuit
impedances, electro- magnetic radiation, vacuum tubes, transistors, integrated circuits, radio wave production and propagations and the various
electro- mechanical devices.

The B &K Precision Model 1470.

The compact 5 -inch solid -state 1470 is
specially designed to meet 80% of a6 industrial
scope applications.
It has DC to 10 MHz bandwidth with 10 mV /cm
sensitivity. Sixteen triggered -sweep spsed3 range
from 1 usec /cm to
0.2 sec /cm. Triggers on
input signals as low as 5mV.
Sound good? Our prices
become even more
remarkable once you
see our specs.
Call your B &K
distributor. Or write
Dynascan Corporation.

8995

ENCYCLOPEDIA OF INSTRUMENTATION AND CONTROL, by Douglas

M. Considine, Editor -in- Chief. McGraw -Hill Book Co., 330 W. 42nd Sf.,
New York, NY 10036. 91/2 x 73/4 in. 788 pp. Hardcover, $29.50.
Bringing together the many facets of scientific information which can
be termed instrumentation and control technology, this comprehensive
Encyclopedia provides a bridge between the underlying principles and the
techniques of applying instruments and controls to whatever work there is
to be done. Of great importance to the user, the Encyclopedia is a convenient desk reference, designed for rapid and easy use. Fully cross- referenced, with in text cross references as well, it contains an extensive alphabetical index, a classified index and a contents wheel to permit the user to
locate desired information rapidly.

r.

In stock at your

parts distributor.

Product of
Dynascan Corporation
1801 West Belle Plaine Avenue, Chicago, ltiinois 50613
Circle 77 on reader service card

1972 POPULAR TUBE /TRANSISTOR SUBSTITUTION GUIDE, by TAB

Editorial Stall. TAB Books, Blue Ridge Summit, PA 17214. 81/2 x 51/2 in.
256 pp. Vinyl Cover, $4.95. Papercover, $2.95.
New up -dated and expanded edition of the only substitution guide
available that lists best substitutes for all popular tubes and transistors.
The new volume contains eight sections, four devoted to tubes and four to
transistors. Section provides a cross -reference of popular American receiving tubes. Section II lists substitutes for popular tube types found in
commercial and industrial equipment. Section III provides a cross- reference of popular foreign /American tube types and Section IV shows the
base diagrams for all tubes. Section V is a complete listing of popular
American transistors. Section VI lists American substitutes for the most often encountered foreign transistors. Section VII lists general -purpose replacements. Section VIII presents base diagrams of transistors.

Designed and manufactured in U.S.A.

NEVER
A BURNOUT

HOW TO REPAIR ELECTRICAL APPLIANCES, by Gershon J. Wheeler.

Reston Publishing Co., Inc., Reston, VA. 9% x 61/4 in. 224 pp. Hardcover,

slo.00
Using this book, it is possible to fix anything from a faulty lamp switch
to a washing machine by following the easy step-by -step instructions. The
basic methods described are clear, safe and useful to any man or woman
who owns an appliance. Some of the many items covered in the text include heating pads, waffle irons, electric irons, vaporizers, three-way
lamps, solenoids, blenders, can openers, garbage disposals, dish washers.

COMMERCIAL RADIO OPERATOR THEORY COURSE, by Martin

Schwartz. Ameco Publishing Corp., 314 Hillside Ave., Williston Park, NY
11596. 9 x 6 in. 448 pp. Softcover edition, $5.95.
An ideal book for anyone studying for his first or second class commercial radio operator's license. It is complete in its coverage of radio theory and it covers all the information needed to pass the FCC exams. In addition, over six hundred FCC -type multiple choice questions are given. No
previous technical experience is required since the course starts with basic electricity.
PULSE & SWITCHING CIRCUITS, by Harvey F. Swearer. TAB Books,
Blue Ridge Summit, PA 17214. 53/4 x 83/4 in. 254 pp. Hardcover, $7.95.
For anyone interested in the science of electronics, particularly those
involved in its practical day -to -day aspects, the use of pulse and switching
circuits is a vital concern. There is hardly a phase or field of electronics
untouched by some form of pulse and switching applications. This book is
not an engineering text; it is a practical examination of pulses, the circuits
that shape them and the variety of ways they can be put to work. It begins
with an examination of pulses, basic definitions and pulse parameters.
From there it continues to progress to pulse generators and circuit response characteristics. The remainder of the book is devoted to a variety
of practical, everyday applications, including remote control, computers,
radar, telemetry and various automation devices.
R -E

DIODE- PROTECTED
NOBODY ELSE BUT EMC
DESIGNS IN SO MUCH VALUE!

LifeProfessional quality and versatility

No
time protection against electrical abuse
meter burnout, needle damage, or fuse replacement

VOLOMETER
Model 109A Factory Wired & Tested $30.95
Model 109AK Easy -to- Assemble Kit $22.65
20,000 c /v DC sens. 10,000 t, /v AC sens.
41/2 ", 404 meter. High impact bakelite case.
5 DC voltage ranges: 0 -6 -60- 300 -600-3000v.
5 AC voltage ranges: 0-12 -120- 600 -12003000v. 3 DC current ranges: 0- 6- 60- 600ma.
3 AC current ranges: 0- 30-300ma; 0 -3A. 3
resistance ranges: 0.20K, - 200K, - 20 megs.
5 db ranges:
to +67db. With carrying
strap. 51/4" W x 63/4" H x 27/s" D.

-4

POCKET SIZE VOLOMETER

Model 102A
Factory Wired & Tested $18.95
Model 102AK
Easy -to- Assemble Kits $15.95
31/2", 2% accurate 8004 D'Arsonval
type meter. One zero adj. for both
res. ranges. High impact bakelite
case. 5 AC voltage ranges: 0-12-120 600- 1200.3000v. 5 DC voltage ranges:
0 6 60- 300600- 3000v. 3 AC current
ranges: 0 -30- 150-600ma. 4 DC current
ranges: 0- 6-30- 130ma; 0 -1.2A. Resistance: 0 -1K, 0 -1 meg. 33/4" W x 61/4" H
tc

2"

Send FREE

catalog of complete EMC line

and name of

nrare:t distributor.

RE -11
Name

Address
City
State

Zip

EMC

ELECTRONIC IMERSUREMENTS CORP.

625 Brcadway, New York, N.Y. 10012

D.

NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

91

TRUE TRIGGERED SWEEP

OSCILLOSCOPE /VECTORSCOPE

next month

MODEL
TO -50
DC to 10 mhz
frequency response

DECEMBER 1972

.02 volt sensitivity

Calibrated vertical
attenuator

Now The Transistor Is 25

December 23 marks the 25th anniversary of
the transistor. Here's a look at its short yet
long, and very exciting history.

Calibrated time base

Supplied with combination Direct /Lo-Cap
probe

magnifier

5 X

Automatic triggering
mode

5" flat face tube

edge -lit graticule

One Year

Warranty

33950

Made in U.S.A.

See your distributor or write Dept.

RE-11

LECTROTECH, INC.
5810

N.

Circle

Western Ave., Chicago, Illinois 60659

78 on reader service

Build An IC Breadboard
More than just an easy way to interconnect
components, this unit has a built-in power
supply and clock generator to speed circuit
development.

card

Evolution Of The Calculator

Calculators, it seems, have been around for
quite some time. Here's an in -depth look at
how man has progressed from counting on
his fingers to electronic marvels that solve
complex problems in fractions of a second.

Clever Kleps

Keyed Rainbow For Faster Troubleshooting

The lowdown on how to use a color -bar signal generator effectively inside a color TV
chassis.

Test probes designed by your needs-Push to seize, push

to release (all Kleps spring loaded).
Kelps 10. Boathook clamp grips wires, lugs, terminals.
$1.19
Accepts banana plug or bare wire lead. 43/4" long.
$1.39
Kleps 20. Same, but 7" long.
Kleps 30. Completely flexible. Forked -tongue gripper. Ac$1.47
Lepts banana plug or bare lead. 6" long.
Kleps 40. Completely flexible. 3- segment automatic collet
firmly grips wire ends, PC-board terminals, connector pins.
$2.39
Accepts banana plug or plain wire. 63/4" long.
Kleps 1. Economy Kleps for light line work (not lab quality).
Meshing claws. 41/2" long.
$ .99
Pruf 10. Versatile test prod. Solder connection. Molded
phenolic. Doubles as scribing tool. "Bunch" pin fits banana
jack. Phone tip. 51/2" long.
$ .79
specify. For additional information,
All in red or black
write for complete catalog of
probes, plugs, sockets,
connectors, earphones, headsets, miniature components.

ue
INDU

92

7 N

1.

PLUS:
Solid -State Design
Step -By -Step TV Troubleshooting

-test

Available through your local

distributor, or write to:

INC.
RYE INDUSTRIES
Mamaroneck, N.Y. 10543
128 Spencer Place,

Service Clinic
Appliance Clinic
Equipment Reports

In Canada: Rye Industries (Canada) Ltd..

Circle 80 on reader service card

Circle 79 on reader service card

NOVEMBER 1972
RADIO -ELECTRONICS

www.americanradiohistory.com

..

technotes
DAMPER DIODES-RCA CTC22, 41, 42 AND 43
It is advisable to use two diodes in parallel when replacing the solid -state damper diodes in these chassis. (Note: The
damper diodes are supplied by two sources. The black plastic
barrel portion of one is slightly larger than the other. Always
use two of the same configuration.)
WRAP AND SOLDER LEADS.
DRESS AWAY FROM OTHER
COMPONENTS.
DRESS
CAPACITOR

AWAY FROM
DIODE LEADS.

CLIPS MUST
HOLD DIODE
SECURELY.

CTC 22

Two diodes, similar to those previously supplied except

that they will have leads attached to each end, are available
under stock number 135320. The single diodes without leads
will not be available.
To install, wrap the diode leads together and solder.
Make a good electrical and mechanical bond. Keep leads as
short as possible, clip off excess. Space diodes approximately
Ya inch apart for easier installation. Install the diodes as
shown in the appropriate drawing.
WRAP AND SOLDER LEADS.
DRESS AWAY FROM OTHER
COMPONENTS.

D 102 (in the high- voltage regulator circuit) can cause increased screen current in the horizontal output stage, resulting
in lower screen voltage and reduced vertical sweep.-Magnavox Service News Letter

MAGNAVOX T946
A condition of horizontal jitter in this chassis can be
caused by leakage in capacitor C66 -the .001 -F, 1000-volt
unit connected between terminal 4 on the flyback transformer

and low end of the horizontal oscillator coil. The degree of

jitter depends on the amount of leakage. Severe leakage
through this capacitor can disable the horizontal oscillator
and result in no high voltage.-Magnavox Service News Letter
SOUND DISTORTION ON CATV SYSTEMS
This complaint refers to G -E C2/L2 color chassis. The
set performs normally on an outside antenna. On CATV,
careful fine tuning will usually produce clear sound but use of
afc will result in one or more stations with distorted sound.
The problem is caused by the cable sound- carrier levels
being more than 17 dB below the video carrier (broadcast ratio is 10 dB). Sound sensitivity can be increased with a
EP50X6 sound kit. Receivers beginning with serial numbers
5G40.... have the new circuit-G-E Service Hints
R -E

AT LAST!
HOME PROM:C[10N
EVERYONE CAN INS1ALL
AND AFFORD.
Model FC-100

WIRE$5
CLIPS MUST
HOLD DIODE
SECURELY.

CTC 41, 42, 43

Caution: Relatively high voltages exist between the

damper diode terminals and other components in the adjacent area. These components include capacitors, the metal
chassis, board terminal stakes and associated leads and the
printed circuitry on board PW400. Be sure the diode leads are
dressed well away from these components. Make certain the
mounting clips hold the diodes securely in position after
dressing leads properly.-RCA Television Service Tips

MAGNAVOX T936 AND T956

Reduced vertical sweep may be a complaint on early
production runs of these chassis. The + 140-volt supply for
the screen grid of the vertical output tube (V 106) is developed
from a voltage divider in the screen -grid circuit of the horizontal output tube (V 103). In these chassis, leakage in diode

995

Start your custom

Burglar /Hold -up /Fire Alarm
System with the FC -100.
Add on Sensors, Alarms
and Accessories to suit your
own needs.
"Do -it- Yourself" Installers
Handbook included. No
technical knowledge needed
No soldering.
100% Professional in Design, Reliability,
Performance.

`fail Safe =SYSTEM BY EICO

A New Concept in "Do- it- Yourself "Home

FREE

Protection

32 PAGE EICO CATALOG

For latest catalog on EICO Test Instruments, Stereo, EICOCRAFT

Projects, Environmental Lighting, Burglar /Fire Alarm Systems,
and name of nearest EICO Distributor, check Reader Service
Card or send 250 for First Class mail service.
EICO, 283 Malta Street, Brooklyn, N.Y. 11207

Circle 81 on reader service card

NOVEMBER 1972
RADIO -ELECTRONICS

www.americanradiohistory.com

95

THE ONE WORD

AND RELIABILITY IN
ELECTRONIC IGNITIO

YOU
CAN HAVE

TOMORROW'S
IGNITION ON
YOUR CAR TODAY
Proven by over 100,000
for over five years.

in

(continued from page 68)

8- CIRCUIT USED TO TEST POWER

TRANSISTORS. The base current steps of Fig.
7 are amplified by transistors 03 and 04.

the emitter circuit is proportional to the

current flowing through it. This voltage
is applied between the vertical input of
the scope and ground. Hence the vertical deflection is proportional to the collector (and emitter) current.
On the 443, different circuits are
used to accommodate pnp and npn
transistors. The circuit in Fig. 7 -a is
used for a pnp device. Q1 and Q2, along
with the associated circuitry, establish
the steps for the base circuit in an interesting manner. Assuming the negative
cosine wave of Fig. 7 -b appears across
the secondary of power transformer T1,
the base of Q I is negative with respect
to the emitter for the first quarter cycle
up to 90 . The transistor conducts and is
in saturation. The collector of Q1 approaches the emitter voltage of the transistor. Meanwhile, the base of Q2 is
negative with respect to its emitter, so
that it does not conduct and its collector
remains at the supply voltage potential.
Resistors R48 +R37 and R34 + R33,
connected to the collectors of Q 1 and
Q2 respectively are the components of a
voltage divider. The voltage resulting
from the divider action and from the
relative voltages at the collectors of the

transistors, forms one step at the SIGNAL beta control. R47.

In passing, it should be noted that
some WET and IGFET characteristics
can be tested on the 443. Once you
know the current in milliamperes per
step fed to the base, you can change the
input steps into volts per step by merely
adding a 1000 -ohm resistor from the
base to emitter terminal. The steps fed
to the transistor are normal for the enhancement mode of operation and is
quite satisfactory for most IGFET's.
For JFET's, the bias should be in the reverse direction. However, it may be
used in the direction supplied on the
443 for gate to source values up to 0.5
volts, if there is to be no conduction between the gate and source. The Toss
will, of course, be the lowest step established when V08 = 0. Vp can be determined from this curve. The ratio of the
difference in drain current between the
IDSS step and the next step, to the difference in gate voltages establishing these
steps, is the gmo.
Extended use and imaginative applications are not limited to the engineers. Technicians can use any ac transistor tester to check transistors in
(continued on page 98)

USING THE CURVE TRACER

FOR PERFORMANCE

operation

Don't accept "as good as" there are

none.

Write Today for Literature

s117
asoMir
RESEARCH AND MFG. CO.

CONSHOHOCKEN PA.19428
Circle 82 on reader service card

FIG.

BUYING
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4-50' HANKS HOOK -UP WIRE 51

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Chotee assortment .
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ANY 6 KITS FOR S5
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300
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Selection
100 -ASST 1/4 WATT RESISTORS $1
stand. choice ohmeges, some in 5%
100 -ASST 11/2 WATT RESISTORS $1
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70
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96

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51

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IMMEDIATE DELIVERY
Scientific light packing for safe delivery at minimum cost.
HANDY WAY TO ORDER: Pencil mark or write amounts wanted in each box, place letter
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Tearsheets will be returned as packing slips in your order, plus lists of new offers.

Minimum Order $3.00

FREE GIFT

t;':sBlry;

NOVEMBER 1972

www.americanradiohistory.com

N. Y. 10024

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USE YOUR MASTER CHARGE OR BANKAMERICARD

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8 assorted Units we
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RADIO -ELECTRONICS

97

HARD -TO-FIND

USING THE CURVE TRACER

FOR ELECTRONICS AND FINE MECHANICS

circuit. The curve tracer is an ac transistor tester. To be sure, the curves will not
be as logical nor as valuable as when
the transistor is tested out of circuit, but,
in some distorted manner, these tests
will show four steps and indicate that
there is gain if the transistor is not defective. A shorted transistor will appear
as a single vertical line on the `scope
while an open transistor will appear as a
single horizontal line.
The circuit in Fig. 7 -a does not supply enough base drive to accommodate
a power transistor. A position on the
FUNCTION switch is provided for this
type of device. In the 443, two transistors are added to the collector circuits or
Q1 and Q2. They increase the current at
the collectors enough to drive the base
of a power transistor. The circuit is
shown in Fig. 8. The performance is exactly as discussed above for the signal
device, except that now, the POWER dial
must be used for beta measurements. It
is accurately calibrated in beta when the
maximum collector current step is at 1
ampere. All suggestions listed for diverse tests in the signal transistor discussion can be applied here as well. I
am certain you will find a few more!
Only a curve tracer will provide reverse characteristic information about a
diode economically. The 443 will test
the breakdown of rectifiers up to 2000
volts and show leakage current down to
1 mA per division. A protection switch
and flashing warning light are provided
on the front panel to alert the user that
high voltages are present.
The forward and reverse breakdown voltages of SCR's can likewise be
tested. Connect a 1000 -ohm resistor
from the gate to the cathode and connect. the cathode and anode to the tester
as you would an ordinary diode. Advance the VOLTAGE ADJUST control and
note the reverse breakdown voltage of
the SCR. The forward breakdown voltage can be measured by simply reversing the connections of the SCR to the
tester. The holding current can likewise
be observed in this test.
The 443 must be connected to a
scope to observe the various displays.
Inexpensive scopes using ac amplifiers
are perfectly satisfactory. However, due
to capacitive coupling, you will find it
necessary to reset the vertical and horizontal controls for many of the measurements. In addition there will not be
a true dc level so that you will be unable
to note leakage current on the set of collector curves. You will, however, be
able to measure it quite accurately using
the reverse diode test position.
The best solution is obvious. Use a
scope with horizontal and vertical dc

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used by electronic technicians, instrument mechanics, engineers, scientists.
Over 1700 items listed. Write today.
Qvaarzoozm

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--

NOW $4.95

TV TECH AID BOOKS ARE FILLED WITH THE LATEST QUICK -SERViCING
INFO ON COLOR TV, B &W TV, AND STEREO
.

..

right to the source of the trouble without guess

work and wasted time. In each monthly issue you receive over 40 actual
causes and cures of color and B &W TV trouble symptoms. You also
receive timely and complete information about circuit modifications and
other valuable service data.
TV Tech Aid Takes you

USE THE COUPON BELOW TO PLACE YOUR 1972

SUBSCRIPTION (12 ISSUES $7.95) OR VALUABLE BACK ISSUES

SEND YOUR CHECK

OR MONEY ORDER

1969 12 Issues $4.95

1970 -Book Form $4.95

Book $4.95

1971 12 Issues $7.95

1971

B &W

1972 All New 12 Issues $7.95

TO:
Name

TV TECH AID
P. O.

Address

Box 603

Kings Park
N.Y. 11754

City

State

Zip

(continued from page 97)

amplifiers.

98

Circle 87 on reader service card

NOVEMBER 1972
RADIO -ELECTRONICS

www.americanradiohistory.com

R -E

SPECTACULAR!! PRICE WAR ON SURPLUS SEMICONDUCTORS

SANKEN HYBRID AUDIO
AMPLIFIER MODULES

LINEAR 111..' ICES, OP AMPS, REGULATORS

a 709 High
Li

711 Dual

performance Op-Amp

Comparator

5.50

50

......$1.25
723 Regulator
741 C.ompenwted Op-Amp.
$.50
Dual
741
558
$1.011
$2.25
LM309 5 Volt I amp Regulator. TO -3

CHIP SPECIAL

......

FAIRCHILD VOLTAGE REGULATOR

Fairchild UGH7805 5 Volt 1 amp
voltage regulator. Perfect for logic
applies, very compact
$1.95

and F has purchased a quantity of MOS large orale

integration chips for calculators. We are not allowed
to mention the manufacturers name, however, the
specs should make them self-evident.
Four 24 pin 1.C.'s, BCD output, 16 digit,
Set "X"
fixed automatic decimal point, possible memory
B

$29.00
"Y" - Single 40 pin, 7 segment output 12 digit,
$15.00
fixed automatic decimal. no constant . .
Set "Z" - Single 411 pin LC., 7 ergotent output.
$I9.50
8 digit, floating point, constant
expansion, constant

SPECIAL I.C.'S, PHASE LOCKED LOOPS

NE560 Phase Locked Loop
NE561 Phase Locked Loop
NE562 Phase Locked Loop
NE565 Phase Locked Loop
.l NE566Function Generator/Tone Encoder
tl NE567 PLL/Tone Decoder .
1 NE595 Four Quadrant Multiplier
NE555 Timer, 2u Sec to 1 hour, Special
NE540 Power Driver, for 100w AB amp.

Set

$4.65
$4.65
$4.65
$4.65
$4.65
$4.65
$3.75

7400 SERIES TTL SUMMER CLEARANCE

MOST POPULAR I.C. SERIES MADE

$1.25
$2.25

MEMORIES, SHIFT REGISTERS, ROM'S

1101
1

1103

u 7489

256 Bit RAM,MOS

1024 Bit RAM,MOS

$4.00
$8.75

64 Bit RAM,TTL

$3 75

. - ,

2513 Character Generator ROM.

1402 Shift Register
.
it 1403 Shift Register
n 1404 Shift Register
8224 Programable ROM.

$14.75
$4.00
$4.00

....

$4.00

$14.75

Dear Customers.

want to take this opportunity to thank you for your

patronage. Your response. has in a few short years allowed
is to grow to become one of the largest surplus dealers in the
U.S., and because of our buying power, we are able to offer
you "state of the art" components at prices the hobbyist can
abord. Offering the latest technology though, has its pitfalls.
Sometimes manufacturers, promising us the latest in LED's.
MSI, or other advanced technology, have had problems get
ting their production lines going and have delayed shipment
to us which resulted in a delay to you. We hope you will
understand this at these times and accept our apologies.
in order to offer you still better service in the future, we
have made some significant changes here at B & F. We have
formed a mint venture with Aries Inc. to develop, manufac
lure and market kits Only (You will find their ed elsewhere
in this nagazinel. The engineering staff represents some of
the finest engineering talent in the United States. even if we
say it ourselves. The division leaves us free to pursue the surplus business and to devote our full time to servicing your
orders and finding new "buys'.
We also have increased our staff and can now offer more
service on information requests. Please keep them simple.
however, as we can not do the engineering for you, but will
do all within our power to provide you with complete data
on everything we sell,
Thank you again, and we look forward to many more years
of offering you the latest in electronics and electroaptical
technology.
Very tryly yours,
We

Franklin

G.

7400
7401

7402
u 7403
7404
0 7405

7406
7407
7408
7409
u 7410
u 7411

.22
.22
.22
.22

0 7451
0 7453
0 7454

.27
.27
.50
.50
.30
.30

0 7470
0 7472

.22

7426
7430
o 7437

.32
.22
.53

u 7438

7 11(1

7446
7447
7448
7450

07473
0 7474

0 7475
0 7476
0 7480

.22

7421

7113
7114
7 f t5

07460

.22
.27
.55
.50
.50

7413
7416
u 7417
7420

Fink

07481
07482
0 7483
0 7485
0 7486
0 7489
07490

0 7491

0 7492

.22
.22
.22
.22
.40
.36
.48
.48
.76
-53

1.62
1.17
1.10
1.37
.22

1.55
1.13
1.55

230

0 74155

0 74156
0 74157
0 74158

74160

0 74161

o 74184

07496 -1.12
-

0 74154

.76
1.12
1.12

1.21
1.21
1.21

74100
74107
74121
74122
74123
74141
74145

0 74151
0 74153

o 74162
0 74163
o 74164

0 7493
o 7494
o 7495

74150

.72
2.45
2.45
1.55
2.45
.55
4.00
.76
1.35
.76

.53
.22
1.64

o
o
o

1.44
.49
.53
.67
1.06
1.55
1.33

74165
74166
74167
74170
74180
74181
74182

0 74185
o 74190

1.39
1.39
1.48
1.48
1.79
1.79

With these you can build

your own audio amplifiers
at less than the price of
discrete components. Just
add a power supply, and a
chassis to act as a heat sink. Brand new units, in original boxes, guaranteed by B and F, Sanken and the
Sanken 1 S. distributor. Available in three sizes:
10 watts R MS (20 watts mush power), 25 watts RMS
(50 watts M.P.) and 50 watts RMS (100 watts M.P.)
per channel. 20 page manufacturers instruction book
included. Sanken amplifiers have proved no sinople
and reliable. that they are being used for industrial
applications, such as servo amplifiers and wide band
laboratory amplifiers.
o SI1010Y
10 watt RMS amplifier,

industrial grade
25 wall RNS amplifier,
industrial grade
cl SI1050A
50 watt RMS amplifier,
industrial grade
o S11025E
25 watt RMS amplifier.
entertainment grade
SII050E
50 watt RMS amplifier,
entertainment grade
ti Transformer for stereo 10 watt amplifiers
(2 lbs,)
Transformer for stereo 25 or 50 watt
amplifiers (5 lbs.).
u Set of (3) 2000 mfd 50V capacitors
for 10 watt stereo
Set of (3) 2200 mid 75V capacitors
for 25 or 50 watt amplifiers
4 Amp Bridge Rectifier, suitable
for all amplifiers

$4.75

S11025A

$14.75
$22.50

$14.00
$21.00
$3.95

... ...

ri Complete

$5.95
$4.00

$5.00

$2.00

kit for 100 watt RMS etereo

amplifier (200 watt music) including two

50 watt Sanken hybrids, all parts instructions, and nice 1/16" thick black ano-

1.79
1.79
3.75
3.75
3.75

dized and punched chassis

Same for 50 watt RAIS stereo amplifier.
includes two 25 watt Sanken, etc.
Same for 20 watt RMS stereo, includes
two 10 watt Sanken, etc.
SGS

$88.00

$58.00
.

830.N1

TAA 621 AUDIO AMPLIFIER

I.C. audio amplifier in 14 pin DIP package. provide,

up to 4 watts power with proper heat sink. and 28 Volt
supply. Can be used at 12 Volts with reduced output
power. -$195
6 for $10.00
D

4.75
5.75

16 DIGIT POCKET CALCULATOR

1.13

4.90
-

1.13

295

COMPLETE WITH
CARRYING CASE
AC/DC TYPE

2.95
2.95

7419 2.45
74192

0 74193
0 74194
0 74195

1.87

295

0 74198

0 74199

1.87

1.95
2.65

2.65

UNBELIEVABLE? A COMPLETE POCKET

CALCULATOR FOR ONLY
$99.00
ere closing out some demonstrator Sanyo pocket calco
lators for only $99.00, This is a complete unit with nickle
radium battery. Has eight digit LED display, with sixteen
digit capability. Fixed automatic decimal at 0, 2, or 4 places.
Units are demonstrators, but are in original factory cartons
with guarantee cards, instructions, etc. Carries full one year
factory guarantee by Sanyo. Only 35 available so order now.
We

- invaluable for high power

applications, motor speed controls.
lighting circuits welding controlo,
etc. Never before at this low price.

SCR's

Brand new packaged devices comeat and 24 page

plete with data
consumer applications manual.

2N5062
D 2N5064
0 2N4169
o 2N4170
2N4172
O 2N3525
2N 1772/C 15A
2N1774/C15B
0 2N 1777/C 15D
0 2N1844/C20A
0 2N1846/C20B
0 2N5169
2N5170
2N5171
2N3896/C30A
0 2N3897/C30B
0 2N3899/C30E

inventory of

over one million brand new, factory packaged integrated circuits,

and is continually buying more
from sources throughout the country. N e intend to
offer these at the lowest prices of any supplier, and
to prove this point we have just cut our own normally
fantastic low prices even lower. We will meet or better any 7400 series price. Data sheets are included
with all items. On orders over $20.00 we will include
free, TTL data book or Linear data book, totaling
over 200 pages Orders over $100.00 will receive
1000 page data file. An additional discount of 5%
will be allowed for orders over $250.00 and 10% for
orders over $1000.00.

HIGH POWER SCR's

B and F maintains an

71.11

Peter E. Boniface
Partners B & F Enterprises

fortunate
purchase of Sanken Audio
Amplifier Hybrid Modules.
We have made a

CALCULATOR

Plastic 100V amp

Plastic 200V I amp
100V /8 amp stud
200V /8 amp stud
400V /8 amp stud
400V/3 amp press fit
100V/8 amp stud
200V /8 amp stud
400V /8 amp stud
100V/12 amp stud
200V/12 amp stud
200V/20 amp stud
500V /20 amp stud
700V/20 amp stud
IOOV/25 amp stud
200V /25 amp stud
1

500V/25 amp stud

$.35
.40
1.45
1.65
1.95
.95
1.75
1.95
2.50
1.75
1.95
3.75
4.75
6.75
2.95
3.95
4.95

FLAT NYLON LACING TAPE

One pound tube of black lacing. about 1,000 yards
should last the average hobbyist several years. Usual
price is $10.50. At this price you can use it for all
kinds of applications besides lacing. Test over 50 Ibs

Lacing Cord

lb.

$2.00

Sanyo Pocket Calculator

AC Power Pack /Recharger

59900
$19.00

SANKEN HIGH POWER, HIGH PERFORM- ALL ITEMS WHERE WEIGHT NOT SPECIFIED
ANCE HYBRID VOLTAGE REGULATORS
POSTAGE PAID IN THE U. S. A.
These hybrid regulators are easy to

Phone in charges to (617) 531-5774 or (617) 532 -2323.

requiring no external componMastercharge. $10.00 minimum. No
ents
Excellent for operational BankAmericard
amplifier supplies logic applies C.O.D.'S please.
and other high performance app//nur
lications. All regulators have lese
$10.00
than 50 millivolts ripple and better
master charge Minimum
BANNAMERICARO
than 1% line and load regulation,
Charge
some models far exceeding this
a./rnu.r /ru
specification.
use,

S13120E 12
O

O
O

Volts

Ampere
SI3150E IS Volta, I Ampere
S13240E 24 Volts I Ampere
SI3050E 5 Volta, I Ampere
S13554M 5 Volta, 3 Amperes
1

Circle 88 on reader .service card

$2.25
$2.25
$2.25
$2.25
$7.00

B. &
P

F.

ENTERPRISES

Phone 16171 532 2323

Box 44. Hathorne. Massachusetts 01937

NOVEMBER 1972

RADIO -ELECTRONICS

99

circuits

SAVE
MONEY:
A Delta Mark Ten Capacitive
Discharge Ignition (CDI) System
On Your Car Slashes Maintenance
Costs And Increases Performance.
Put a Mark Ten on your car and save
by eliminating 3 out of 4 tune -ups.
Save as gasoline mileage increases
(up to 20 %). The Mark Ten CDI System
also extends spark plug life, promotes

more complete combustion and

assures instant starts in all weather.
It operates on any 6 or 12 volt negative
or positive ground system.
The Mark Ten B affords additional

money saving advantages by drastically reducing combustion contaminants and restoring power lost by the
use of smog control devices. Equipped
with handy switch for instant return to
standard ignition, the Mark Ten B
works with ANY 12 volt negative
ground engine. Both systems install
in ten minutes without rewiring.
Order your Mark Ten or Mark Ten B
today. Save money while you enjoy
low maintenance and increased
performance.
Mark Ten (Assembled) $44.95 ppd.
Mark Ten (Deltaklt) $29.95 ppd.
(Kits available in 12 volt only,
positive or negative ground)

Mark Ten B $59.95 ppd.

112

volt negative ground only)

Superior Products at Sensible Prices

Mfg. in U.S.A.
Dept.

RE-1

DELTA PRODUCTS, INC.

GRAND JUNCTION. COLORADO 81501
PHONE (303) 242 -9000
P.O. BOX 1147

A SIMPLE ALARM
Need a simple alarm? A 3pst relay
with normal open contacts will solve the
problem. From the schematic, once triggered the alarm sensor and on /off
switch are bypassed. The on /off switch
is a toggle switch, thus saving the extra
cost of a key operated switch. For optimum protection, it is suggested that the
power source he wired direct to line,
thereby eliminating an obvious line
cord. For the same reason, the alarm

In order to acquaint you with our

unique, universal wiring board, we'd
like to send you a sample .. free
of charge. You'll find it a great timesaver in circuit construction and it
eliminates the need for etching, drilling and tools. Send for your free
sample today . . . You'll be glad
.

OPERATING
VOLTAGE
INPUT

you did.

ON OFF
SWITCH

VERO ELECTRONICS Inc.

171 Bridge Road
Hauppauge, N.Y. 11787
Circle 90 on reader service card
N.O.
SENSOR

ALARM

OVER RIDE
(CONCEALED)

Draw
the line
on contact

failure...

should be attached to the same box as

the relay. With this scheme, the only
visible wire would be the alarm sensor
and by the time an intruder noticed this
wire, the alarm would be on and an attempt to cut this wire would end in negative results. The concealed over-ride
switch is a major feature of this system.
The ingenuity of the constructor will
dictate type and access to this switch.
A form of self test can be performed by operating the alarm sensor, a
test for power as well as component
failure. In addition, relay life should be
optimum.-Herbert C. Olney
R -E

with an Electrolube pen.

A newly developed

contact treatment that:

Prevents tarnishing
Inhibits arcing
Reduces contact resistance
Improves reliability
Special introductory
coupon offer. Regular $2.50
Electrolube pen

only $1.95.

Please send me literature immediately:

Enclosed is S
Ship ppd.
Ship C.O.D.
Mark Ten B @ S59.95 ppd.
Please send'
Standard Mark Ten (Assembled) @ $44.95 ppd
Positive Ground
Volt: Neg. Ground Only
Negative Ground
12 Volt: Specify
Mark
Ten
(Deltakito)
@ $29.95 ppd.
Standard
(12 Volt Positive Or Negative Ground Only)
Make
Car Year
Name
Address
Zip
City /State

GUARD THOSE YOU LOVE

__

100

GIVE TO THE

AMERICAN
CANCER
SOCIETY

Electrolube Corporation
155 Michael Drive
Syosset, N.Y. 11791
Please send me one Electrolube pen.
enclose $1.95.
I

Name

Address
City

I.

Circle 89 on reader service card

NOVEMBER 1972
RADIO -ELECTRONICS

www.americanradiohistory.com

State

Zip

Circle 91 on reader service card

50 MHz DIGITAL COUNTER

LABORATORY SPECIFICATIONS
AT A BUDGET PRICE!

We feel the most important thing about building a kit

is saving money. There are a lot of other advantages
of course . . maintainability, use of standard parts,

AIRCRAFT /AUTO/BOAT QUARTZ

CRYSTAL CHRONOMETER
Revolutionary!, was the reaction of our customers
when they saw our latest kit. Measuring only 2-1/2"
x 2-1/2" x 4", and accurate to 10 seconds a month.
this chronometer promiaes to entirely replace meets
ancial clocks in cars, boats and airplanes
Fits into a standard 2-1/4" instrument panel cutout.
The displays are bright L.E.D. displays that should
last a lifetime. Setting controls are recessed and operate from a pointed object such as a pencil point or
paper clip, in order to keep non-authorized hands off.
The clock should only have to be reset at very great
intervals, or in the event of power loss (i.e. replacing
battery in car). The clock is wired so that the timing
circuits are always running, but the displays are only
lit when the ignition is on, resulting in negligable
power drain. The low price ie only possible because
of a new one chip MOS clock circuit, developed for
quartz crystal wristwatches.
Operates from 10-14 Volts D.C. An accessory unit
which mounts on the back adapts the unit to 20.28
volts for twin engine aircraft and larger boats using
24 Volts ignition. Know how disgusted you are with
the usual car clock? Order this fine unit now for rallying, sports events, navigation, or just to have a fine
chronometer that will give you a lifetime of superbly
accurate time.
Quartz Chronometer, Kit Form
$59.50
o Quartz Chronometer, Wired
$99.50
0 24 Volt Adapter
$10.00

aa9a']L

-...

complete documentation, and the experience and fun

of building it, but the overriding consideration iseconomy. This kit costs less than half that of the lowest
priced competitive unit on the market.
The Aries 50 MHz counter is designed for years of
maintainence free service. MSI integrated circuitry,
cold cathode display tubes and conservatively rated
transformers mean low temperature rise. All displays
and I.C.'s are in sockets for easy maintainability. The
master oscillator is a 1.0 MHz crystal in a custom de
signed cosmos oscillator circuit, having a stability of
3 PPM. Accuracy is 0.005% worst case, 0.0002%
or better when adjusted to WWV with a communications receiver. A front panel selects a timing interval of 1.0 seconds, 0.1 seconds or 10 milliseconds.
A variable monostable multivibrator holds the count
on the front panel for a period of a fraction of a
second to infinity. For use in the period mode. the
1.0 MHz oscillator is connected to the main counting
chain and gated by the input signal.
Assembly time for the kit is approx. 10 hours. The
semiconductor complement is (1) 7400, (1) 7408,
(1) 7442, (10) 7490, (2) 74122, (6) 74141, (1) 74193,
(1) 74196, (1) 74511, (1) CD 4007AE, (1) LM309,
(6) Diodes, and (1) Transistor. If you always wanted
a laboratory quality counter, but could never justify
the price, here is your chance.
50 MHz Counter Kit, Complete with Crystal Time
Base and Case
Postpaid in USA
$125.50

Due to the tremendous demand for B & F Electronic

kits
new company, ARIES/BF, has been formed.

This move provides a complete, well staffed organization to deal with kits and only kits, thus offering
faster delivery, better service. and most important of
all, a continuing flow of new kits that will advance
the "state of the art" in their fields.
The activities of the entire staff of ARIES/BF will be
devoted full time to satisfying your needs and providing you with a large selection of interesting and
up- to-the- minute kit devices for the home, the car, and
the electronic shop.
Although ARIES is still at the mercy of vendors for
their delivery in some cases, every effort is being made
to develop sufficient inventory to be able to assure
off-the -shelf delivery of all our kits.
Sincerely,

DIGITAL CLOCK KIT WITH NIXIE DISPLAY

Because we have made an extremely good purchase
of over 20,000 nixies, we can sell a complete digital
clock kit for less than the usual cost of the display
tubes alone. We provide a complete etched and thruplated circuit board, all integrated circuits, complete
power supply, display tubes, I.C. sockets and a nice
front panel with polaroid visor. We have never seen
anyone offer this kit for less than $100 -00 before.
Includes BCD outputs for use as with timer option.
May be wired for 12 or 24 hour display. Indicates

hours, minutes and seconds.

Clock Kit, complete less outside cover .
0 Aluminum blue or black anodized cover

$57.50
$4.50

AUDIO AMPLIFIER KIT

This is not our prettiest kit, but it sure does perform.
Hybrid Sanken audio modules snake wiring easy. Output ratings are maximum continuous at 1000 Hz with
a distortion leas than 0.5% into a load of 8 ohms Response is
0.5 db 20.20KHz @1 watt. Chassis supplied is heavy gunge anodized aluminum. Capacitors
are all computer grade. Level controls on both inputs.
100 Watt (RMS) Stereo Kit
$88.00
50 Watt (RMS) Stereo Kit
$58.00
20 Watt (RMS) Stereo Kit
$30.00

CALCULATOR KIT
Just one evening puts it together. Even if you have
never assembled a kit before, our comprehensive step
by -step manual makes it easy. This calculator adds,
subtracts, multiplies. divides - multiplies & divides by
a constant. Has full 16 digit capacity with 8 decades
of display and zero suppression. Entries and answers
with greater than 8 digits can be displayed in their
entirety in two alternate sections: the last eight digits
and those digits exceeding eight. Negative results are
correctly displayed, and an error symbol indicates an
overflow beyond the 16 digit capability. Sequential
operations can be performed using the answer to the
previous operation as one of the entries for the next.
The decimal point can be positioned following any of
the eight least significant digits and will be caned
automatically during subsequent operations An additional good feature, concerning the beginner, is that
all major components are in sockets, making troubleshooting easy. And if all else fails, (an unlikely occurance) you can send it back to Aries and we will fix
it for a maximum of $10.00, no matter what is wrong,
baring grow negligence.
Kit with Power Supply & Case
.$99.00

Dear Customers

'iCiC.6tt'a+K'

,...,,

16 DIGIT ELECTRONIC DESK TOP

POCKET CALCULATOR
expected a favorable reaction to our calculator,
however, we were overwhelmed when we received
orders for hundreds at a time. The reaction of our
customers was that they felt this was the most advanced pocket calculator on the market, and priced so

We

low, they could assemble and market it at a profit.

The features that make this so exciting are:
So compact it fits in a shirt pocket (3 -13/16 x
4-5/8 x 1 -1/4).
Performs every function you would expect in a
desk calculator, and them some, multiplies, divides, adds, subtracts and gives true credit balance.
Includes constant and chain operation, full floating decimal, suppressed trailing zeroes, and automatic single entry squaring.
Powered by self contained AA batteries with up
to six hours operation (Nicad batteries with charger option, up to five hours per charge).
Calculations performed by
single 40 pin LSI
(large scale integration) chip. Displays are 8 digit
LED's (light emitting diodes) and overflow and
minus signs are also LED's.
As a student, engineer, salesman, accountant or anyone who would like fast accurate answers, this calculator fills the bill, and at a price that unquestionably
makes this the lowest price high quality calculator

Arthur Pennell
President, ARIES /BF

ARIES INC.
Sig Foster Street, Peabody,

Mass. 01960

(6171532 -0450
Please send:

Amount

Description

Qty.

Name
Address

Zip

City /State
Check Enclosed

Master Charge

BenkAme ;card

M.C. No.

available.
Pocket Calculator Kit
Pocket Calculator Completed
NiCad Batteries & Charger
Batteries & Charger Completed

Circle

92 on reader service

$75.00
$99.00
$17.50
$25.00

B.A. No.

Explratio Date
Please c

II

Bank No

factory for quantity prices

card

NOVEMBER 1972

www.americanradiohistory.com

RADIO- ELECTRONICS

101

(continued from page

of

ONO

11/41'

/s\

Modules,
Speakers,
Stereo, HI- Fl,
Photo Cells and
thousands of
other

Elettroni.

Parts. Send for

FREE
Catalog

11161111.1111.1

MIME

ELECTRONIC DISTRIBUTORS INC.

Dept TA -2, 4900 Elston
Chicago, III. 60630

.
.

RUSH CATALOG

Name

Address
City

State

Zip Code

mum um mom im

111

Circle

III
II
-

95 on reader service card

59)

dition of each battery can be read by

turning the meter selector switch to
BATT TEST. To save battery power, the
on -off switch is a spring - return type.
Power is drawn only when readings are
actually being taken.
For receiver alignment, a double
PIN -diode attenuator is used. This provides accurate control of the rf output
over the entire range from 25 to 1000
MHz. This is a special voltage -controlled device. The control voltage applied can be monitored by placing the
selector switch in the A position.
Receiver i.f. stages can be accurately aligned by installing the proper
crystals. Any frequency between 5 and
20 MHz can be generated on fundamentals, and up to 40 MHz using harmonics. A lot of dual-conversion receivers use a 5.0 MHz "High i.f.," so this
one could be very useful.
Internal construction of the instrument is rugged. A heavy PC board
holds two IC's, used in the counter circuits, 5 transistors, plus the other parts.
The whole thing is housed in a rugged
steel case, with storage space in the lid
for calibration charts, cables, the pickup
antenna, earphones, etc.
For the operating tests, we took it
out to the local airport. We checked several of our friend's aircraft (and some
found wanting!) and tuned up. Even in
the crowded quarters of the "offices" of
some of these Bamboo Bombers, we
had no trouble using this convenient
little instrument. All in all, a very compact, accurate and useful instrument,
and one that will make some difficult
R -E
jobs a lot easier.
.dye 1.stng cemnbufed for the eoUK good

too

12 REASONS
YOUR CAR NEEDS
A TIGER 500
Instant starting in any weather - Eliminates
tune -ups - Increases gas mileage - Increases
horsepower 15% - Improves acceleration &
performance - Spark plugs and points last
up to 70,000 miles - Reduces engine maintenance expense - Amplifies spark plug
voltage to 45,000 volts - Maintains spark
plug voltage to 10,000 RPM
Reduces
exhaust emissions - Dual Ignition switch Unconditional guarantee for original owner
Installs in 10 minutes on any car with 12
volt negative ground - No rewiring - Most
powerful, efficient and reliable Solid State
Ignition made.
SATISFACTION GUARANTEED

SOCKET

the EL

EQUIPMENT REPORT

FOR PEOPLE

WHO NEED PEOPLE.

i_,+ u.1e%:-;:-.-t
S

Test new circuit ideas...

I. C. circuits...

discreet components...
at no risk!
Money back guarantee!

All you need are #4 mounting screws

just plug -in components
.
like 1/4 watt resistors, ceramic capacitors, diodes, I.C.s, transistors
and more
and your circuit's
built! No special patch cords
needed! Components interconnected
with any solid No. 22 -26 gauge wire.
And you can try it with absolutely no
risk for 5 days. If not satisfied, just
return your EL Socket and receive a
full refund. Trying is believing. How
can you go wrong? Order your EL
Socket now!
Nickel /silver plated terminals
very low contact resistance
Low insertion force
Mounts with #4 screws
Initial contact characteristics beyond 10,000 insertions
Vertical, horizontal interconnecting matrices
Accommodates wide range of wire
and component leads from
8015"- .032"
.

Send check or M.O. today!

Add 50 for postage and handling

25% deposit on C.O.D.s

1

The American Red Cross.

D EL INSTRUMENTS, INC

61 First St., Derby, Conn. 06418

1J Telephone: 203; 735 -8774

S THE MOST UNUSUAL

Kind Chimes
Th. original baclopound muse .y.btm.
cenmrw ofd id.. r.produoM .Newoni.
oily. Trimmer odjurmr.nh meet dto
rwo of bets chin.. of Rto {ornately.
r..nrurto d b.mboo rad.. U.. with

or money back.

Assembled

Post Paid in U.S.A.

KITS AVAILABLE

.ry

$49.95

No. 3721

Send check or money order with order to:

816.95

Other Kits: SURF SYNTHESIZER NO. 3711

$11.95
SOLID STATE BIRD NO. 1710
S 6.95
Plus electronic music accessories and many more
Please add 50e postage & handling to orders.
.

Star Corporation
Dept. R, P. O. Box 1946
Grand Junction, Colorado 81501

DEALER INQUIRIES INVITED

102

EL Instruments, Inc.
61 First St., Derby, CT. 06418
EL SOCKET(S) 5 $17.25
Please rush
enclose
each, for which
plus 50 for postage and handling. I understand that may try it FREE for 5 days and
may return it for a full
if not satisfied
I

refund.
NAME

STREET
CITY

Writ. for FREE Catalog

PAIA Electronics, Inc.

Box 014359. Oklahoma City, Oklahoma 73114

Circle 94 on reader service card

RADIO -ELECTRONICS
NOVEMBER 1972

www.americanradiohistory.com

STATE

ZIP

Circle 93 on reader service card

market
center
CONSTRUCT Quality but very inexpensive inverter transformer for CD ignition or other uses.
Dollar brings instructions. HOFFMAN Box 838,
Enterprise, AL 36330

BUSINESS OPPORTUNITIES
START SMALL HIGHLY PROFITABLE ELECTRONIC PRODUCTION AT HOME. INVESTMENT, KNOWLEDGE UNNECESSARY. Postcard brings facts. BARTA -RAH, Box 248, Walnut
Creek, CA 94597

EMPLOYMENT Information -Electronic Technicians -How to earn 15.000- 20,000 yearly. Not
field service. Not over seas. Work in U.S.A. Detains 3:00. W.L.D. CONTRACT ENGINEERING,
8450 Anthony Wayne Ave., Cincinnati, OH
45216

OWW
F=C
a%
n
s
D3

103
104
105
135
165
153
159
161
170
100

IM

D5
1)7

D8
R2
11.7

R9

511
R47
R99

CTS

OTO

231

GT7
GT8
GT29
GT36
GT38
GT40
ST2

232
233
632

639
641
643
51
54
55
56

CONVERT any television to sensitive big -screen

oscilloscope. Only minor changes required. No
electronic experience necessary. Illustrated
plans $2.00. RELCO -A25, Box 10563, Houston,

8T20 310

BT11 240

8T14 243
8T17 246

8TI8

247

ST25 703
ST26 709
ST42 721

8T89 3001

FEI'1

FEr2

801
002

FET3 003
TH5 320

RItI

175

DESCRIPTION

WW

oq

o:_

o)

n.

Zeuer Diode 6.2V 1W 5% DO-7

Zener Diode 9.1V 1W 5% DO-7
Zener Diode 12V 1W 5% DO-7
GE Diode 1N60 Subst.
DO-7
Sel Dual Diode Com. Cathode
8
Si Pwr Rect 200V 15A
DO-4
Si Rect. Az lead 800V 2.5A DO-41
Si Rect Az lead LOV 3A
20
Si Rect. Az lead 1000V 2.5A DO-15
B+ Boost Rectifier 800V
6500 volt Focus Rectifier
30
GE RF Tr PNP 250 bLHZ TO-18
GE Pwr To l'NP 15A
TO-36
GE Pwr Tr PNP 7A
TO-3
GE Pwr Tr PM' 15A
TO-36
GE Audio Ampl. PNP
TO-5

GE Drift-Field PNP
TO-18
GE RF Ampl. NPN
TO-5
GE Audio Pwr Ampl. PNP TO-66
Si RF Tr PNP 150 MHZ
TO-5
Si RF Tr NPN 30 MHZ
TO-5
Si RF Tr NPN 200 MHZ
TO-92
Si VHF Doc. NPN 750 MHZ TO-92
SI Pwr Tr NPN 300V 10W TO-66
Si Med Pwr Tr NPN 60V 3A TO-5
Si Med Pwr Tr PNP 60V 3A TO-220
SI Pwr Tr NPN 70V l0A
TO-3
TO-92
Si T7ni1unction Tr 300mW
Si Audio Pwr Ampl. NPN TO-66
TO-3
Si Audio Pwr Amp! NPN
SI Audio Ampl. NPN
260 MHZ
TO-92
Si RF Pwr Tr NPN 65V 5W TO-5
Fet Audio N Channel
TO-46
TO-46
Fet RF N Channel
TO-46
Fet Audio RF P Channel
Thyristor (SCR) 30V 800ma. TO-18
Full Wave Bridge 50V 3A .750/.600Rd

.70
.70
.70
.16
.38
1.32'
.40
.66
.55
.60
1.20
.77
1.36
1.65
2.97
1.10
.99
.88
1.15
.77
.66
.70
.88
1.20
1.10
1.32
1.70
.99
1.76
1.43

1.50
2.30
.99
.99

2.10
.60

.60

Terms: Add 250 for postage

Minimum Order 2 Dollars.
Send 100 for Complete catalog.

INVENTIONS & PATENTS

GF Electronics
P.O. Box 14

Greenwood, Mass. 01880

INVENTIONS Wanted Patented; Unpatented.

GLOBAL MARKETING, 2420-AE 77th Ave.,
Oakland, CA 94605

TRONIX ORGAN PRODUCTS, Dept. B, 5872

Amapola Drive, San Jose, CA 95129

J
a>

CC*. A.

I-

8T5
8T6
8T7

BUILD your own TELEPHONE ANSWERING

SERVICE. Put your TAPE RECORDER to work.
Detailed plans $3.90. TONASCOPE -E, 400 Third
Ave., Satellite Beach, FL 32937

ANTIGRAVITY DEVICE. Brochure rushed free.

AGD. Box 3062, Bartlesville, OK 74003
ELECTRONIC ORGAN KITS, KEYBOARDS for
music synthesizers and organs. Every corn ponent for organ circuitry. 25e for catalog. DEV-

-J

PROFITABLE ELECTRONICS DEVICES. Plans,

instructions, sources and COMPLETE BUSINESS SETUP. LET YOUR SKILL PAY! Free literature. BARTA -REH, Walnut Creek, CA 94597

TX

PLANS AND KITS

EVERYTHING IN SEMICONDUCTORS
YOUR CHOICE FROM OVER 300 POPULAR
DEVICES. IF YOU DON'T SEE IT HERE, ASK
FOR IT.

Circle

101 on reader service

card

"WINTER SALE" NEW GUARANTEED DIP IC'S

CLASSIFIED COMMERCIAL RATE (for firms or individuals offering commercial products or services). 900 per word
minimum 10 words.
NONCOMMERCIAL RATE (for individuals who want to buy or sell personal items) 606 per word
no minimum.
FIRST WORD and NAME set in bold caps at no extra charge. Additional bold face at 10C per word.
Payment must accompany all ads except those placed by accredited advertising agencies. 10% discount on 12 consecutive insertions, if paid in advance. Misleading or objectionable ads not accepted. Copy for January issue must reach us before Nov. 1.
.

7400 7401 7402 7403

7405 7410 7420 7430
7440 7450 7453 7454

CLASSIFIED ADVERTISING ORDER FORM

2

441

7446
7472
7473

5
DM

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

EACH 5.90

74L74
HOT PRICES!!

7448

EACH 5.23

LOW POWER UNITS -WHY USE BIG

EXPENSIVE POWER SUPPLIES? THESE
IC's USE ONLY ONE TENTH THE CURRENT
74L00 74104 74L08
EACH 5.40
74L10 74120 74L30 74L51

74L73

7404
7408
7460

DM
DM
DM
DM
DM
DM
DM
SE
SE
SE

7442
7447
7483
7474
7476

EA.
EA.
EA.
EA.
EA.

EA.
EA.
7493 EA.
7496 EA.
74192 74193 EA.

7475
7486
7490
7495

$1.10
1.10
1.40
.45
.50

SOPHISTICATED IC'S
$1.90
8200
4 Bit Magnatude Comparator
(Indicates Less -Than, More -Than, or Equal)
Presettable 4 Bit Counter
1.30
8281
Modulo N Divider -25 MC
1.90
8520
1.90
8570
8 Bit Serial -To -Par. Shift Reg.
1.90
8590
8 Bit Par -To- Serial Shift Reg.
Version
Lo
of
DM
8570
2.50
86L70
-Power
8601
1.20
Retrig. Mono. Multivibrator
8880
2.50
7 Segment Neon Decoder -Driver
Function Generator-TO -5 Or Dip 3.25
566
567
Tone Decoder-TO -S
3.25
Phase Locked Loop
565
3.25

THE MONSANTO

MAN -1

DISPLAY

L.E.D.-7-SEGMENT-D.I.P.
26

27

31
No. of Words

32
1

.60 Non-Commercial Rates

.90 Commercial Rate
No. of Words in bold caps
@ .10
@
@

Total Enclosed

Insert
Starting

29

30

33

34

35

NAMF

PROGRAM FOR $5.00 MORE

CITY_

through accred.
ited advertising

SIGNATURE
MAIL TO: RADIO- ELECTRONICS, CLASSIFIED AD DEPT.,
200 PARK AVE. SOUTH, NEW YORK, N.Y. 10003

28

COPY

8223 FIELD PROGRAMABLE ROM

256 BIT WITH 32 8 -BIT WORDS
ONLY $8.00 ALSO -WE WILL

=5

Payment must accompany order un-

agency

"LIKE"

Volt -1 amp Regulator -To -3

$2.25
Package-Short- Circuit Protected
Visible Light Emitting Diode
.60
LM 351 Dual Driver -Each Driver Has
1.90
TTL 2 -Input Nand Gate Control Of
Output Transistor Rated Up To 30V -.3A
2.25
LM 380
2 Waft Audio Amplifier

SS

issue

'

OR

M -309K 5

=5

less placed

"SIMILAR TO"

NOT SOME

ADDRESS

time(s)
with

28

$.75
.55
.75
1.00
1.80

STATE

ZIP

-IF

WANTED

All Shipments First Class Mail -Free

To You

Missourians -Add 4% Sales Tax

JTM ASSOCIATES

P.O. Box 843

Manchester, Mo. 63011

Circle 102 on reader service card

RADIO -ELECTRONICS
NOVEMBER 1972

www.americanradiohistory.com

103

wOg10 FAMOUS

SE

ON

FA

0
D
O

O
O

6D

channel.

S, forSCRS
TRIGGER DIODES,

$1

Si
Si
$1
Si

51
51
$1

Si

S1

51

'

By

19

SLIM -7

Flourescent Blue -Green

SOc
Seckel
Filament V.
W.
Characters
s
H.
.360 .570 1.5V AC /DC 42 mils
MINI.7 1.75 a 1.7
1.5V AC /DC 42 mils
.40 n .20
a 0.375
SLIM -7 1.6
Compatible te 7- segment driver IC's.
KIM -7
MINI -7
All 3 kern O-5 numerals. decimal, and letters.
3- 2N2646 UNIJUNCTIONS, plastic transistors, Cesas
5 - 2N1O7, GE, mbet commonly used pop, germanium

'

3
SO
SO

SI

-3 -AMP 1000 PIV epoxy bullet, silicon rectifiers

leaden

sl
si

-SILICON, glose rectifiera, computer, axial

-GERMANIUM, glass rectifiers, signal, axial leads-2N170, GE, RF, germanium, npn, transietora, TO -22
10 -1 -AMP 1000 PIV, epoxy, submini, silicon rectifiers
30 -500 MW ZENERS, axial 4, 6. 9, 10, 12V rectifiera
4 -2N3055, HOBBY, 40W non silicon transistors, TO-3TO -8
5 -2N155, HOBBY, 101V pnp germanium transistors,
3 - 50 AMP SILICON RECTIFIERS, silicon, 6, 12, 24 volte
S -2N1038, TEXAS, germanium pnp, 20 watts, TO -6, w /sink
30mc
10- 2N3054 hobby, npn, TO-66, silicon, 80W.
10 -SCRS, assorted voltagea, TO-5, TO -18, TO -46
?n -3 -AMP RECTIFIERS, silicon, epoxy, assorted V. axial' .
r SN7441N, hobby, BCD -to -Nixie driver LC, DIP
10 -LINEAR AMPS, 709, 710, 711, 741, TO -6
10 -709 LINEAR AMPS 741'. too, DIP
S -HOBBY MEMORY CELLS SN7481, up to 16 -cell, DIP
10 -709. 710. 711 LINEAR AMPS, brand new. flat pak
2 .2N5296 35 -WATT NPN PLASTIC TRANSISTORS for any 540
2 -2N6109 40-WATT PNP PLASTIC TRANSISTORS for any 640
5

Cl

-723 VOLTAGE REGULATORS, TO -5

cane
4.1000 NFE DARLINGTON transistor., TO -187 amp
85 watts
1 -2N5036 HI PWR plastic trans 100 vceo.
2 -2N5296 HOBBY 35 watts, plastic powere NPN
2 -2N6109 HOBBY 40 watts, plastic Dowers PNP
Untested tiaranteed a ishTtion
LED -PHON -SOLAR 'DOLLAR STRETCHERS'

-- "LEDS
-IR
", visible, lambo,
2"LEO ". invieible, parabolic reflector,
tore,
3-- "LEDS
"LEDS ", visible, M101,1
", infrared, jumbo, TO-
2
1
1

4
5

----

axial !ende

si
si
S1

SI

Si
SI
Si
SI
$1
Si
$1
51

red, TO

SI
SI
SI

.......

si
SI

RCA

TRANSISTOR, with darlington ame filiar. lens

TRANSISTORS, with darlington ame. 2N5777, GE.
CELLS. Clairex, pancake, 305.70 ohms
CELLS round. en. rent., suo power cir Elite
SILICON SENSORS. TEXAS, II -38 Motchstix cvisible
PHOTO
PHOTO
PHOTO
SOLAR

SI
S1

61

Si
Si

$1 PARTS "DOLLAR STRETCHERS"

30 POWER RESISTORS, 3- to -mow, aguare, vitreous. Y
REED SWITCHES, 2" long, fastest mock. switch
8
30- MICRO REED SWITCHES 1e long, traneietor work
SUPER ECONOMY

-10 - TRANSISTOR SOCKETS, for pnp -npn trans powers too

- $23. SURPRISE PAK, resistore, caps, transistors, etc,
60- TERMINAL STRIPS, -to -8 screw & tie lugs

ss

40

& TV KNOBS. asst chapes, colore, styles

-- RADIO
SQUARE DISCS, 86mmf to .01mf, apace-savers
-FORMED DISCS, condensere, printed circuit
-- PRE
PHONO PLUG- AND -JACK SETS, tunes, amps. doublet too
LENSES, piano convex, concave, convex, mirror
-- RODAR
TUBE SOCKETS, receptacles plugs, sodio. etc.
PREFORMED RESISTORS. i/2 watt, printed ckt
-- DIPPED
SILVER MICAS, pop reluce, silvers, too
& CHOKES, if, rl, ant, peaks, ose, parasitic
- COILS
'IC' SOCKET- ADAPTERS, TO-5 DIP, flat, handy
RESISTORS t/8. 1/2, i & 2W. % seat val
-- PRECISION
TUBULAR CONDENSERS, to .6mf, to 1kv, molded too

30
75
10
10
60
100
30
50
10
60
60
10

SN7430
SN7437

Sale

51.

SI.
SI.
SI.
Si.
Si.
51.
Si.
Si.

.21

5N7474
5N7475
SN7476

.50
.51
.21
5157441 1.00
SN7442 1.12
5157443 1.21
SN7444 1.21
SN7445 1.50
SN7446 1.40
SN7447 1.10
SN7448 1.25
SN7450
.21
SN7451
.21
5157453
.21
SN7454
.21
SN7460
.21
5157470
.39
SN7472
.32
SN7473
.44
Factory Marked.

5.21
.21

51.47438

SN7440

.21
.21

.27
.27
.45
.45
.29
.29
.21

.25
.50
.48
.48
.21
.21

.32

20%

kit (with vices'

.39
.71
.44
.65
1.10
.88
1.25
.49

SN748O

SN7481

5157482

SN7483
SN7486
SN7490
SN7491
SN7492
SN7493
5147494

SN7495
.93
SN7496 1.10
SN74107 .49
SN74121 .49
SN74122 .67
SN74123 .99
Factory Guaranteed!
,-

ad'
~

Completely wired, ~m'y

S1.

tee--i-

WITH CASE

Smaller

8"

&

more compact
3" case

x 5t/2" x

8 -DIGIT ELECTRONIC POCKET

kit hou
and advanced battery operated pocket
$100. Makes use of the smallest
(Large Scale Integration), LED dis-

CALCULATOR
Betterr and Electric
Includes Battery

Chart

099.95
Uses LSI Chip
& LED Display

Factory

Gift paked.eSise:

NEW FOR 1973!

at
Never before offered at this price! You've seen them
but now et a price calculator users
$175, $149
has 16h
can afford. EIGHT -DIGIT fluorescent display and
Div digit capacity. Adde! Subtracts! Multiplies!
MINUS
ideal in chain or mixed calculation.. Includes
OVERFLOW
balance.
credit
negative
sign showing
(K)
INDICATOR 10 to the eight power, CONSTANT
4. 6 decimal
MEMORY switch. Floating decimal or 2. 8. calculator
of
points as required. (CE) key clean tinning vero
last entry error. Automatic loading and
suppression. LSI (Large Scale Integration) equivalent
epsed
to more than 8,000 transistors. Calculation
I.
adds and subtracts 10,000th of a second. Keyboard
REED SWITCH seeembly for extensive trouble -free
116
operation. Separate power switch, Removable
Wt.
cycles.
VAC
50
-60
VAC line cord. Power 110 -120
silver
8 lbs. Handsome black molded cabinet with
trim, sise: 9t/2" x 51/4" a fit/a ". Complete with

51.

Brand New

CLOCK KIT

snap-action keyboard.
use or
away
ccan be thrown charger
(included).
the AC power
Performs Addition, Subtraction, Multiplication, Division functions, including Chain or Mixed Multiplication
to
and Division, ae well ae true "credit" balance up the
10 digits. For added convenience and simplicity digit
the eight
decimal point I. fixed to two places Indenote
overflow
display. Additional display indicators
beyond the eight digits and negative result (minus
instruction booklet.
Includes
nrantee
gua

1.45
1.25
1.25
1.13
1.23
1.95
1.39
1.39
1.25
1.48
1.79
1.79
1.79
1.79
1.10
4.50
1.10
1.75
1.75
1.19

By Scientific

Mont economical
calculator under
single chip LSI
play technology
The 9V battery
recharged with

mere,

10%

dIseeuet

"ONLY"

SN74141
SN74145
54474150
SN74151
SN74153
SN74154
SN74155
SN74156
SN74157
SN74158
5N74160
SN74161
SN74162
SN74163
SN74180
SN74181
SN74182
SN74192
51574193
5N74195

3.50
.69
1.10
.71
.71
1.10

5157489

Indicates HOURS, MINUTES. SECONDS. 115 VACoff80

Take 10%
Buy 3
cy. Gift packed. Wt. 8 lbs.

Si.
Si.
SI.
Si.
Si.
51.
Si.
SI.
etc. Si.
Si.
Si.

SN7400
SN7401
5N7402
SN7403
SN7404
SN7405
SN7406
SN7407
SN7408
SN7409
SN7410
SN7411
SN7413
SN7416
SN7417
SN7420
SN7421
SN7426
300
Take

Buy 3

by type number! Spec sheets on request

Devices'' give
patience in des!gp!ng to give
nearing dept, took extra patience
the latest techyou the finest digital clock kit
understand booklet. The cabinetniques in an
touch
making section gives it the "interior decorating"
any room at home, ehoD
into
fit
may
it
that
o
front cabinet, with
office. Walnut laminated tapered easy
Large
viewing.
gold -line front. Tapered legs for
"blue- green" polaroid
7-segment fluorescent
G.E.
8 display
FEATURES:
viewing.
easylatest
the
glow for
board,
tubes, completely etched and thru plated circuit
timer
all IC's. Includes BCD outputs for me with

SI

.si

10 -RCA CA -3000 OP AMPS, TO -6 cbee

st Selection TTL 1

"DIP" Packages Order

The lowest price digital clock

far as we c. see in U.S.A.

D MINI -7

f.

Type

S1

Floureseent Blue -Green

50e
Seeket

7 -SEG. READOUTS

2.50

$1
$1
$1

--

only axial) ads

ALPHA -NUMERIC
3 for

Li

Stretchers

2N3055 npn, 100w I5A, TO -3, transistor

-92, plastic transistor
2- 2N3572 l' 11F,1000mc, npn, TO SCRs
& Triaca
6 -ER900 TRIGGER DIODES for
4 -2.5 AMP 1000 NV ITT, silicon epoxy rectifiers
lOpf, 20p, 3opf, 40pf, 50p1
5- VARACTOR DIODES,
2 -FET'S 2N5457 N channel 5000 umho.. TO-92 plastic
1 -90 WATT PNP, 15A, 2N2612, TO -8, silicon
3 -2N389 npn, silicon, 85 watts, Vice 80, aguare case
3- 2N1212 npn, silicon, 85 watts, Vice 60, stud case
10 -1N914 fast switch diodes, silicon 4 nanoseconds
10 -215404 germanium pnp, TO-6 chrome case
2 -6 AMP TRIAL 200 PR V, TO -6
40 -G -E MICRO MINI RECTIFIERS, silicon. porcelain to 1 KV
assorted volts
40- RECTIFIERS A ZENERS, IW. & 1A. bullets,
1W, assorted volts.
30- WORLD'S SMALLEST RECT. & severe,
1 - FAIRCHILD 2n3919 80mc, 15W, npn, 10A, TO -68
5 -2N3638 PNP, silicon, TO -6 plastic transistors
5 - 2N3641 NPN, silicon, TO-6 plastic transistors
4 -2N4269 Nixie tube driver transistors 100V, npn
2 -PET'S 2N3085 N channel, 10,000 umho TO -18 traneiston
2 -PUTS, pros. ni- transistors, similar to GE-D13T
2 - 2N2606 P channel, 2500 umho, TO-18
1 -

O
O

D ollar

booklet.
CALCULATOR BYE A MAU, ORDER
ADVERTISER. Gift Packed!
Uses single Texas Instrument "Chip"
Features found In more ex enslve units

GUARANTEED

'Uaique Scientific Device, "hand claps ",

tal mike amplifier, triggers SCR. Needs
Use as burglar alarm, intrusion device.
cell, triaser. SCR's, relays. LED's, Eves
pipe may be used. With hand booklet.

sensitises crysonly 8 to 6vde

Use with photo
fiber optic light

$2.503
TUBE SALE
- SUBMINIATURE IF'S. 455 kce, 045 square, transistor
A -to10 - TUBULAR ELECTROLVTICS to 100mf. for ac /dc sets,
170V.
characters,
high
2.
21/2
NIvir
IL
15 - NE -2 NEON BULBS, for 110050, 100'e of projectsvalues
30 - POLYSTYRENE CONDS. finest cap. made. Yet.
slide, 51.
PHI
10 - PANEL SWITCHES, 110vac, micro, rotary. thermal,
so O5..79 t85
10- VOLUME CONTROLS, to lmeg, duals too. some w /switch 51. EPDXY
.99
100
40 - MICRO MINI
.93 1.25
200
1KV
to
SI.
WAVE
11m
FULL
to
U30- MOLDEO CONDENSERS, Supright,160axial,
mes51.
1% & 5%, AB's too, 100 to
50- ONE WATT RESISTORS,
1.35
i
6
D
600 D
Si. SILICON
10 - TRANSISTOR ELECTRO't, 6mf to 800m, upright too
1.69
1.65
800
Si.

cAlCULATOIR
COMPLETELY WIRED

Only

99.95
NOT
A

KIT
B ur 3

Yaka 10%
D lsceunt

MAGIC

"SOUND
TRIGGER''

LINEAR

FACTORY
FACTORY MARRED

6.Y

Burroughs

FACTORY
111)

AnY 3

PAKf

TESTA

Sale
Description
$2.50
2 50
741 TO -5
power
Micro
1
2 50
Micro power 709
.
2.50
FET Input op eme
2 90
Precision 741 TO -S
10 UPRIGHT TRANSISTOR ELECTRO'. m to 800m diece
1.79
2.25
D
loso
S1.
2.04
npo'e,
.04,
10mmf
to
amp
70W pwr driver
60- CERAMIC CONDENSERS,
O
TO
-6
ease
2
amp
Code:
Si.
1 17
Cerafll
Preclsien 723 voltage reg
40 MICRO-MICRO-MINI CONDENSERS, to .05mf
I/2 x 3/i6 eg
t/2
a
Ante
a
S1.
2 uSeconds to 1 -hour sass 3 fib
IBM COMPUTER BOARDS, trans, caps, res, coils, etc.
Timer
5
too
Si.
!mint DIP)
741
Dual
10 ELECTROLYTIC CONO'.. FP's & tubular, 2 & 3 sect. snap
;28
-inS1.
10K 25K 1 /ew,
TRIMMER POTS, 100, 500, 2Ii,
ON
Phase lock loops (A)
Si,
299 5%
Function generator (Miel DIP)
60 HI -Q RESISTORS, carbon, Ve. 1/2. 1.
D
Si.
Most complete listing!
3 25
Two SCRs in ene cate!
(Mini DIP)
DISC CAPACITORS, 10mmf to .05, npo's, hi -Q, to 6KV
decoder
SO
Ton.
O
asst
51.
310
10 amp 15 amp 25 amp
8 eme
50 MICA CAPACITORS, to .01, to 1KV, silvers too,
3 amp
Four quandrant multipliai
5% asst . Si.
5.85
S.65
1.00
5.45
21er
TO-S
5.35
DC
amp,
35 TWO WATTERS, resistors, carbon, metal-film,
^.
S.22
-gal
50
Hi
1.05
.85
.64
.62
1 00
MICRO POTS w /knob, snap -in. 1 /6W, 26k, 50k 100k. Imeg $1.
4
.35
100
RF -IF, eme. 14 ckts, TO-5
i1.
etc.
1.45
1.25
trans,
electro's,
.88
.72
400 PRINTED CIRCUIT PARTS,
.65
amp (A)
200
Operational
Si.
1.85
&
sises
values
1.45
1.10
39
.89
30 - YELLOW PACKET MYLARS, assorted
.79
300
amp
(A)
Differential
71OC
Si. 400
1.95
nest types
1.85
1.35
1.15
39
10 - POWER TRANSISTOR SOCKETS, for TO-8, high
.92
Dual dig. Comp (A)
711C
2.26
51. 500
speed
2.55
1.39
95
1.25
3 - "MINIATURE" MOTORS, shaft, 8- 12vdc,
Voltage regulator (A)
723C
Si.
2.85
circuit
TO
-18,
printed
1.69
1.50
64 -PLASTIC TRANSISTORS,
600
compensator 70911 ,41
Frequency
741C
10 amp TO -66, 15 & 25 amp stud.
TO
-5,
(A)
741C,
amp
Dual
6
G
3
747C
Quad -2-input NAND gate
L) 551574500
.. $ .99
1 44
First Time
re
O
w/open collector
1 00
709C (DIP)
51574503, SN74SOO
Ever Offered
1 -WATT D 709-709 Dual
STEREO PREAMP
99
1 98
Dual stereo preamp
739
-739
SN74504 He: Inverter
99
'
100
IC
AUDIO
741.741 Dual 741C (A)
SN74SOS Hex inverter (open toll)
99 At These Prices!
8
amp
channel
-739
Dual
739
-749
749
AMP
SN745O8 Quad 2 input AND gate
99 SCHOTTKY
DIP dual in l ine pak
TO -6
B. transistors
51.1745
Trip 88 ut
collector
99
8- translators
per channel.
51574510 Triple 8 Input NAND gate sass 99
Any
In TOS case.
Choose
80,
net
50K in. Imp
add postage, cod's 25 %. Rcted:
51574511 Triple 8 input AND gate
99
400K In. Imp. Terms,
for phono -tape
Phone Orders: Wakefield, Mass. (617) 245 -3829
51574515, SN74811 w /open collector
99
Westinghouset
Retell, 211 Albion St., Wakefield. Mass.
IC'S 20- 20,000 me. 3 for 54.50
SN74520 Dual 4 Input NAND gate
99
TO -5.
WC334.
C.O.D.'S MAY BE PHONED IN
DIP. Fairchild.
SN74521 Dual 4 input AND gate
99
Flip sop toggle
SN74522. 8(074521 w /open collector
99
Parts
15$ CATALOG on Fiber Optics. 'ICs', Semi's.
trap One so
SN74540 Dual 4 Input buffer
99
INTEGRATED CIRCUIT SOCKETS
to 125mha
SN74564 4 wide. 4 -2 -3 -2 in AND-OR Inv 99
Dlscountl
10%
Tek.
Any
3
Buy
SN74573 Dual J -K master slave flip Sop . 1 9s ' Switches
14 -Pin, dual In line ..5.45
4 times tastar
01 5N74574
Dual D edge trig. flip flop . , .. 1 88
16 -Pin, dual in line .. .20
than standard
515745113. SN74574 with preset
P.O. BOX. 942R, LYNNFIELD,MASS. 01940
1 98
TO -5, 8 or 10 pins ..
.

- -6---

66

BRIDGE
RECTIFIERS
LOW PRICES

5K,

'TRIALS'

--

-- -

...
...
...

Buy 3

104

Teka 10% Discount

RADIO -ELECTRONICS

TTL

Type

531
532
533
536
537
540
550
555
558
565
566
567
595
702C
703C
709C

NI slew rata op -amp

...

...

Ai

1.95

POLY PAKS

TTL's

Circle
NOVEMBER 1972

103 on reader service card

www.americanradiohistory.com

EXCLUSIVE ECONOMY -PACKED

Fie 2

Sale

DOUBLE BONUS
BONUS

a t

PA K

,tad 25r for nanao na

Kua CHOOSE

Ics. DIOD[3
R TRANSISTORS

ANY ITEM

=sass

OR

p R KNOBS,

KNOBS, [TC.

s
rRE

BOTH FREE WITH ANY $10. ORDER

NEW LOWEST PRICES

BRAND

GENERAL $2.95 vP'

ELECTRIC 3 FOR 16.00
`i
3-WATT AUDIO AMP l'

(0
{

PHILCO 11 TRANSISTOR
AM RADIO CHASSIS
t9',y
use aft
OMy
PAM. amplifier
;ley',

`'-

4.95

Phone ampliBar
Tape amplifier 77

'

c
OSO K. to
1500 K. Broadcast band
AC or DC
One of the moat versatile AM Radio and mule- purpose
amplifiers we have seen at Poly Paks famous "Economy"
price. Measures only 4t/2" 5 3" x 2" high. With tuning
capacitor, IF circuitry, loopetick, ant., volume control
with switch, AC and phono -mike jacks. Separate switch
for changing from AM radio to amplifier. Uses either
110V plug -in adapter (not with unit) and a 9 -volt
battery power. Exceptional sensitivity and power. Feeds
into 16 ohm speaker. Complete with spec sheets, dia*_y

grams, and hookup ideas.

'

; A,.

8 TRANSISTOR
AMPLIFIER CHASSIS

only $3.95

IT'S NEW! 12 -DIGIT 3 for $35

"CALCULATOR ON A CHIP" 12
Sorry, can't name U.S. maker! Type SD5001.
Similar to Mostek 6012. Outperforms Texas
8 -digit TMS -1802. Features: 40 -pin DIP; not 5,
not 3, but only single "calculator chip ". 12digit capacity; adds, subtracts, multiplies, divides, fixed point (0. 2, 3 or 4 decimal places),
chain operations, leading zero blanking, 7 -segment decoded display output, overflow lockout,
and negative sign output. Drives incandescent,
fluorescent, Nixies, and LED readouts, complete

3.88

t,

MANUALS for Govt. surplus radios, test sets,

scopes, teletypes. List 25e. BOOKS, 4905
Roanne Drive, Washington, DC 20021

:'

o -9 plus

SN7446 or 157447./?
in 14-Pin DIP
% x as%"
o
characters: '/
le per wK,

,11.11,11.11111

Focters

Famous

ETCO
ELECTRONICS, 464B McGill, Montreal, Canada

VATELY- AUTOMATICALLY.

!7

-1

.50

N.

STATE
TUNER

LED READOUT
COUNTING

SYSTEM

cp

II

124

24-709, 710, 711. 723, 741 asst. cases $2.911

24 -7400 Series, Dual in line, asst.
.. 1.980
24- Linear L 7400 Series, east. cases .. 1.980
10 -709, 710, 711, 723, 741, TO -5 ...

1.00

c, 1iuo die.
-2" high, M2unt s I , I.^
hole, with shaft, near,
Tx
1

riu n -proof high

73

100

Ohm-

2.0K

ALLEN BRADLEY
'MICRO -POTS'

7.K

2.3K

")

2 for $1

25.K
75.K

1O.K

500
5.OK
20.K
100.K
5 Meg
We stock Lockout Bushing & Screwdriver types
at same low prices.

ALLEN BRADLEY'S
'TRANSISTOR' POTS
Ohms

75
100
200

2so
500
750

1.0K

2.5K

5 -0K

7.5K
10.0K
20.0K

Type

POLY PAKS

pin DIP

-75

screw rt "er adios`'

100K
200K

25.K
50. K
75.K

2
S

Na.
EA.

Any
es

BE PHONED

ly0 805

IN

Mass. 01940

and two

pages

application

3.50

sheet

3.50
9.50

Also self correcting

ring counter
hookups, etc.
10 LU321 W /data
$4.00

of

notes describing hookups for-divide

by three through ten, and twelve.

All IC's

are new and fully tested

leads are plated with gold or solder.
Orders for $5 or more will be shipped
prepaid. Add 356 handling and postage for smaller orders. California
residents add sales tax. IC orders are

shipped

within

two

workdays
of
receipt of order -kits are shipped
within ten days of receipt of order.
Money back guarantee on all goods
sold.

for

r',

7442
7447
7473
7474
7475
7476

BCD decoder driver

BCD decoder
7 Segment decoder driver
dual 3K flip -floe
dual type D FE
quad latch
dual 31( FT

LIS
1,15
1.60
.65
.50
1.15
.65

o4o

BABYLON

'S`

ELECTRONICS

(10)

two -page

7480 gated full adder

7483 4 bit full adder
7486 quail exclusive or gate
7488 64 bit RAM
7490 decade counter
7491 8 bit shift register
7492 divide by 12 counter
7493 4 bit binary counter
74154 one of 16 decoder
74181 Arithmetic Logic Unit
24

$1.75
$15.00

.80
1.60
.65

..

4.00
1.15
1.15
1.15
1.15

3.00

pin DIP

2.4.50
00

fast carry for above

74192 up/down decade counter

74193 up /down binary counter
74195 univ. 4 bit SR
8280 preset decade counter
8281 preset binary counter
8520 25 MC divide by "N"
2

7495
8590
8270
8570

4
8
4
8

.
.

2.25
2.00
1.15

1.15
1.15

2.00

to 15

hit SHIFT REGISTER 1.15

hit Shift register
2.00
bit shift register
2.00
bit Sr. PO, shift register 2.50

SEND FOR FREE FLYER

`-'V
Circle

105 on reader service

NOVEMBER 1972

www.americanradiohistory.com

TO -5

Teledyne

amplifiers

sheet

of

with

741

application

notes covering the basic

circuits

using op -.M".
$.65 each Op -amp package
10- 791's. data sheet
and

application notes
only $5.00

IC's (dual -in -line)

operational amplifier .. .40
voltage comparator ... .75
LM309K Sv -IA

77090

LMIOOwpositive l voltage l reg. 2.80

747 dual 741 op amp

DIP

40 PIN DIP Package

subtract,
multiply

LED Red Emitting Lamp ....$1.15

8261

TTL dual -in -line

Ten

operational

LINEAR

combination (2 IC's)
ten sets (20 IC's)

Trade Mark

7441

Toren: add postage. cod's 25 le. Rated` net 30

Phone Orders: Wakefield, Mess. 16171 245 -31429
Retail: 211 Albion St.. Wakefield, Maas.
('. O.D,'S MAY

carriers) dual -inline 1K flip -flops -L321 with data

7400, 7401, 7402, 7404, 7405, 7410,

7420, 7430. 7440, 7450, 7451,
7453 ..ea. $.25, 100, any mix, $22.00

F.

LINEAR SPECIAL

DIGITAL SPECIAL
Ten brand new (on

not marked.

Factory To Youl
With Diagrams!
No Test!

Dual In Line 958 decade

L[0

Circle 104 on reader service card

-5

Fairchild
counter and Fairchild 960 nixie*
driver combination. These are new and fullyy gguaranteed but are

7477
7475

8.88

Send 25 for Surplus Catalog

JOHN MESHNA JR. ELECTRONICS

P.O. Box 62 E. Lynn, Moss. 01904

COUNTER IC SPECIAL

7sw

`PIK -A- PAK'FACTORY IC KITS:

.0

DIP

NE567 tone decoder

SYSTEM

tNr
lfor

FOLLOWING ITEMS IN
LIMITED QUANTITY
dual peripheral driver
2 pin DIP
N E565 phase lock loop TO -5
N E566 function generator 8 pin
75451

for

J'
/tl/

Please add postage for above items

BOX

7of/'
tr''

BC 221 except this one

covers range of 20-450 mc. Accuracy .005%
Used, guaranteed OK, less batteries, with schematic.
TS -323 ship wgt 35 lbs.
$50.00

volt regulator
LM309K
This TO-3 device is a complete regulator on a chip. The 309 is
virtually blowout proof, it is designed to shut itself off with overload of current drain or over temperature operation.
Input voltage (DC) can range from 10 to 30 volts and the
output will be five volts (tolerance is worst case TTL requirement)
.
at current of up to one ampere
$10.00
FIVE for
Each
$2.50

4.50
1I2.

323 FREQ. METER

Similar to the familiar

LEAVE

RECORDER UNATTENDED. ROBERT'S,

49RE, PARKRIDGE, IL 60068

READOUTS
UTS
'

TS

INTERCOM, Bogen SA10 -40, 30 Station, Speakers, offers to KOSMAN Box 6251, Lincoln, NE
68506

LOGIC Probe with LED display $20.00 postpaid

U.S. Order from UTI POB 252 Waldwick, NJ
07463

LED

kb

(3

j
-''

iill

CANADIAN Surplus Catalog $1.00.

FM

letter.

KEYSWITCHES

COMPUTER

Another fantastic bargain for the builder. We have

brand new bounce -less micro switch keys, spares
from the above units, less key -tops. Make up your
own keyboards. Made for PC mount. Package of 48
brand new key- switches only $12.00 postpaid.

WRITE for our free 32 page catalog. It lists resistors (14 different types, in kits and singly), 1542
tube types, 3024 different transistor types, many
transistor kits, rectifiers in kits and singly, condensers of various types, tools, wire, antennae,
phonograph cartridges and needles, speakers,
CRT boosters, controls, switches, tv. tuners,
yokes, flybacks, etc. HYTRON HUDSON, Dept.
RE, 2201 Bergenline Ave., Union City, NJ 07087

'

t u'

COMPUTER KEYBOARD W /ENCODER $35

Another shipment just received. Alpha- numerics
keyboard excellent condition. Once again we expect
an early sellout. Price of $35 includes prepaid shipment in the US and shipment made within 24 hours
of receipt of order.

88.108m!tz A AM 5501600kcs. Sensitive 22q x 2.4

x I t/2" module. Can be used
with 10,7mc & 455kcs IF
;oee
strips & any hi -fi amp. P.C.,
4 -gang venable supw[sTttt1w0sa wred.
ply
Rage 9V fi
O
for
diode fur AF['. Schematics.
3 for S I

.'

SOLID
0 AM
-FM

=ii:i:i::iwi1

ELECTRONIC Ignition- Various Types. Information 106. ANDERSON ENGINEERING, Epsom,

with instruction booklet.

Fd
6.t'"it'

111111111111
l X11111 /1111

RECORD TELEPHONE CONVERSATIONS PRI-

except minus the redo,

section of the chassis. 4'/2" x 4" x 2" high.

Same

I,

DIGITAL ELECTRONICS! Complete schematics, parts lists, theories -Discrete Component

Digital Clock, $3.00 -Sound Sensitive Switch,
$1.50. Increase technical competence, hobby
skills -Complete Course in Digital Electronics is
highly effective, $10.00. Limited -Clock plans
INCLUDED with Course! Free literature. DYNASIGN, Box 60R1, Wayland, MA 01778

NH 03239

Delivers 3.5 watts continuous, 10 watts peak. With

heat sinks; micro-mini siz
s/ xt/2n' /a ". 9 to 30V supply. High sensitivity. 8 to 16 ohms. For mono and
stereo phonos. tape. FM. AM, TV, servo.

Awl'.

FOR SALE

Add,

1.10

and

divide.
12

digit display and calculate

Chain Calculations.
True credit balance sign output.

Automatic overflow indication.

Fixed decimal point at 0, 2, 3,
or 4.

Leading zero suppression,

Complete data supplied with
chip.
Complete only $12.95.
Data only $1.00 refundable with
purchase

3 Chip Calculator Set

features
40 Pin
as
Calculator chip above except
digit
display
8
and calculate
Floating decimal point.
Complete with data $8.95

Same

P.O. Box

CARM I CHAEL, CA. 95608

(916) 966 -2111

card
RADIO -ELECTRONICS

105

U.S. GOV'T ELECTRONIC SURPLUS

Naa -Wend Promos SURPLUS CENTER otters
in, Bnmrit Swpin 1rtrenlo units aid
*action or their original aqulsItiN au.

NatlN.Ily

fintt

aver

comp onntt at a

(rtIM

-0141- - Expensive, maIsla null. Fine for college labs, research

rvl<e shops, etc. Pure DC over a wie
a of voltages. DC output voltages 6. 12.
N, etc. Wide age of AC Yolleees available.
A22

Finest trans forums. filters, Deana, load

regulation
on syste.
m Independent of nine voltage
fluctuations. Contains five separate rectifier
furnished
"regulating
be by-passed. Data and circuit diagrams furnished. 30" a 12"
10 ". ( 125 1b.
u.rd,

i11

e.

itingca"

RADIO- ELECTRONICS does not assume

responsibility for any errors which may appear In the Index below.

-.

IBM COMPUTER POWER SUPPLY

READER SERVICE CARD NO

,
-

r k
;'4.

Ay`

$24.95

Cost Gov't
Over $500.00

'

Aries, Inc

88

Bell & Howell Schools

B.F. Enterprises

77

& K, Division of
ascan Corp
Brooks Radio & TV orp.
BSR USA Ltd
Castle TV Tuner Service. Inc

69

PTD. CCT. RELAY BOARDS

92

84

ONCE-IN-A-LIFETIME SPECIAL

-"9

Channellock, Inc.
Chemtronics, Inc.
Cleveland Institute of Electronics
Cook's Institute of Electronics
Engineering
CREE Division of the McGraw -Hill

15
( ITEM #22-9661- - Peer enemata,
ester l 512 .95 such relays.
oa 800prated circuit
r
28-VDC n

bb

twelve

3R"

.:' ua!'

_s

x SS".

Cat

other
s
12 oz. l

same as need
tive polliished Oblack.

thrnghont U.S.A. SW-ac-

,0

mama,
Coer

-- s,'i

nits

6"

a S

".

IM.

IB

Cnl Over

Telephone

did for

o.der as

Item,

W0.00

use with shove

00

89
72

v{s,-,I

I-.
.e-

$6.29
alta9.

$1.97

MAGNETIC DIGITAL COUNTER (12 o16-VDC)

( ITEM 921963) - - One to earn Ieeldnuy.
Use to count number or tams door Is opened after
rene Is closed, to show
aH prices, sluu -

_'.-

.I

transfer
rte Ietc.count to

lap CoM

tbs.

I 1K

war

E. <h

119.00

en i nil.

4%

$1.99

1C n 1%'.
'mree

85

Fordham Radio Supply Co

Grantham School of Engineering

GTE Sylvania Electronic Components

81

91

100

Heath Co

73

Indiana Home Study Institute

International Crystal Mfg. Co
Jensen Tools & Alloys
Jerrold Electronics
Judson Research & Mfg. Co.
Lafayette Electronics

17

$4.99

Fn

83

Edmund Scientific Co
EL Instruments
Electronic Distributors, Inc.
EICO, Electronic Instrument Co,
EMC, Electronic Measurements Corp
Electrolube Corp
Electro-Voice, Inc
E.S. Enterprises

96
93
95

1c,r

mm1li

86
18

200 AMP., 50 VOLT, SILICON DIODE

Lin

over 915.00

I ITEM 4151 I -- 2ealth 115 -VAC unit. Use

for periodic = anaung, work breaks, classes, tom
ON OFF switching
on mdio. e.c. Ad). clips
-day'
Also
hour period.
Eppeenull
has ',kip-a
*2Y
e(n,24

iw-

6W'

"mi a lb..

rill,
n,

'.I

pai

._rJ,

-OHM- AMMETER

121bs

Rep
Puce
39.9S

ELECTRICAL

4
8

RUNNING TIME METER

( ITEM 921811 - - Record number of op.
ling hours or electric lights and electrical
devices such as refriger0ns, furnaces. etc,

in- 4tA
.

Records total hours, tenths and hundredths up

to 9,999.99 hours. For 115-volt. 60- cycles.
Sae 4W'a3.' a 2W. Shipping weight 2 tbs. ig

$4.39

Cost_._
Over 529.00

COMPUTER TRANSISTORS ON HEAT SINKS

IBM Oomputr Quality Units

Unit consists of one 15n.

power trsaslsler on heavy, ribbed,

abate= heat sink. Many experimental
ssox, (1 1b.)
$1.
Cost Gov't Over 1110.00

99

ins-Si

cnni
or two Isepots..
several
lnnlston,
- -

unit

2
power
heavy,
diodes, capacitors. resistors, lc,
ribbed aluminum hest sinks. Ideal for re
s la.)
motor speed control.
Cat Gael Oyer $33.00
1

$4.91

'..

'emu
..T

r, E

&,,. /.

,yi

Schober Organ
Shure Bros
Sony Corp. of America
Supersomc Electronics Co

62
Outside U.S.A.

Obtain technical training al low cost' Lincoln

its Correspondence Courses because
Engineering
are
available, bur
icc. The coursesconi,u
the examination
ne grading
and standard ansisls of 15 lesson bake. each with associated ex
wining
nnone Expetmenlal nbontory
Book describing Prize
furnished
al
no
extra
coat.
Bend,

RCA Institutes
RCA Parts & Accessories
RCA Technical Publications
Robins Industries, Inc
Rye Industries. Inc.
Sans & Co., Howard W.

10

preload Is U.R.A.

I-

--

Radio Shack

11

tatted

Qwetrole

79

En gnee{rinr School has suspended

( 922 121

20
74

$6.79

ENGINEERING

Mall

64

Correspondence
Course In

ITEM 9A ISO

66
21

SPECIAL SAL

Olson Electronics
PAIA Electronics, Inc.
Pennwood Numechron
Perma -Power
FTS Electronics, Inc
Quam -Nichols

13

'.

$36.90

Mountain West Alarm Systems

National Camera Supply Co
National Radio Institute
National Technical Schools
Nelson -Hershfield Electronics

70

ITEM

76

Systems, Inc

opening Me line.Simpi, press's handleAad snap h probe

around the conductor. Reads cu en es Iron ,25 to 125 amp.. Reads voltages to 300, ream ohms up to 500. Test
motors. appliances. eke. Three current ranges. two veilage ranges. With case. test leads. 1S"
S" x Hr.

Micro-Instrumentation Telemetry

63

$15.75

A1 SNAP AROUND VOLT

Cost Gov't
Over 830.00

99

Leader Instruments
Lectrotech, Inc
Lee Electronic Labs

97
78

$4.99

'

AC PROGRAM TIMING CLOCK

82

80

ITEM S2246111- - A Four star Gay' New, leading

Mk.. neavy dug unite nteeu nit for use in 12 or 29 -volt
fast chargers. hash corral power sopplo ansleme, etc.
V" SOS" x n. ". V" -16 SAE mnnung threads. ( 1 ib. )
(

y'.
-

'.

i-.15.

`.
:

All Items shipped f.o.b. Llneola. Nebr.

WRITE FOR FREE CATALOGS

Order Wrest From Ad. Money Beek Oparanta.

SURPLUS CENTER
Dept. RE-112 Lincoln, Nebr. 68501

2
101

24-25
99
91

68

15W RMS HYBRID AUDIO AMPLIFIER -Panasonic -Freq. response 20Hz- 100KHz. 1/2% dist.
Price $6.50 PPD. PACE ELECTRONIC PRODUCTS, Box 161, Ontario Center, NY 14520

HEATH 10 -102 Oscilloscope $110.00. HOWARD

GRUBAUGH 1634 Kimbrough, Springfield, MO
65804

TRIPLETT #603 FET VOM USED EXCELLENT

CONDITION $65.00. HEWLETT -PACKARD
#204C AUDIO OSCILLATOR EXC. $50.00
POSTPAID. ROLAND SINCLAIR,879 Lenox
Road, Brooklyn, NY 11203

96-97
87

Cover II
70
86

BACKISSUE electronic magazines, books. List

256. BELL, 3890 Bayridge, West Vancouver,
Canada

28-31
86
18-21

26

Delta Electronics
Delta Products, Inc
Dictaphone Corp
Dynasaences Corp

$7.49

$24.30

( ITEM
/imaging telephone selector
1 -switch. Great experimental Item. When used with twowmre telephone dial
111 select any number from 0 to 100.
M ke intercom o private system. Use to turn n remote
uehis, mart no a, etc, complete with enact honk.

Continuing Education Co.

Crown International

12

STEP -BY -STEP TELEPHONE SWITCH

l"

14

65

75

new condition. Use

plile e
several phones together for local ntercomnsystem. FLU nsuuctln are furnished. WL 9 lbs.

67

$1.49

Gov't Over 170.00

STANDARD DIAL TELEPHONE

( ITEM SUS).- sererd.
comooreiia
telenl.ne

Y5

components.

PAGE

Amperes

'.y

eeymdeor
wasiitaln

ADVERTISING INDEX

IC MANUAL listing more than 500 common digital IC's with pin connection diagrams, $2.75.
ELECTRONETICS -RE -1, P.O. Box 278, Cranbury, NJ 08512

90
100
89
71

IC

110
102
102
95
91

100
12

97
98
I

32

74-77
90
72
98
73
96
93 -94

Cover

III

92
88
13

84
8-11

46-49

NATIONALLY
KNOWN
BRANDS
SATISFACTION GUARANTEED
DIGITAL TTL

7400N
7401N
7402N
7403N
7404N
7410N
7420N
7430N
7440N
7441N
7442N
7447N
7451N

"5%

United Sales
Yeats Appliance Dolly Sales Co

SCHOOL DIRECTORY
Valparaiso Technical Institute

241

224
224
224
224
$1.20
$1.15
$1.02
224

OFF

l
1

7453N
7454N

74/2N

7473N
7474N
7475N
7476N
7486N
7490N
7492N
7493N
7495N
74107N
74121N

TTL IC PRICES AT 100 PCS TTL ICS

LINEAR INTEGRATED CIRCUITS

27
102

86
81

80
79
90
17

or T0 -5 709....38f, 10/$3.50, 710....38f,

10/$3.50, 741....401, 10/$3 70, 748.. -.430,
10/$3.95 T0 -5 only 723....901, 10/$8.25, Dual
741 (558) TO -5 901, 10/$8.25, Dual 741 (558)
Mini -DIP 751, 10/$6.75 LM 309K T0 -3 $2.25
5/$10.00
DIP

64-67
22
85
16

92

GENERAL PURPOSE TRANSISTORS

2N5134 Si NPN or 2N5138
2N3055 Si NPN Power

23
84

7
15

87

105

104-105
108
107
109
106
107
108
107
108

108
108

Si

PNP..150 8/$1.00

$1.00 10/$9.50

AMP SILCON SUBMINIATURE

RECTIFIERS

1N4001 50 PIV, 1N4002 100 PIV, 1N4004 400

10 /$1.00, 100/$7.50
PIV 1N4005 600 PIV

SILICON SIGNAL DIODES

1N4148 (1N914 equiv.) ....20/$1.00, 100/$4.00

RTL INTEGRATED CIRCUITS

uL900, uL914

&

uL923 Mix

5/$1.00, 100/$15.00

READOUT TUBES
Segment Readout Tube $2.95. Counting and Display Kit (Readout Tube +7490+
7475 -F7447) $5.25, 3 Kits for $15.00
5

Volt

1/2

WATT 10% RESISTORS

40 25/750 100/$2.50 500/$11.25

Pick Values
50f
Complete Digital Data Book
501
Linear Data Book
Free Catalog -Large Quantify Discounts-Orders
Less Than $10.00 Add 254- Others Postpaid

DIGI -KEY
BOX 126H

FOR QUALITY EICS

THIEF RIVER FALLS, MN56701

Circle 106 on reader service card

106

RADIO -ELECTRONICS

NOVEMBER 1972

226
224
356
464
424
724
504
524
724
724
724
$1.05
474
514

MIXED.

'

109

224
220
224
224

OtlIIIIpp g

rl

A`t

89

83
Telematic
78
19
Telex
102
Tri-Star Corp.
94
5
3
Tuner Service Corp
98
TV Tech Aids
87
Vero Electronics
100
90
Cover IV
98
Winegard
71
Electronic
Products,
Inc.
89
Workman
14
7
Xcelite
MARKET CENTER.....- ............. ..- .......- ............._.....- ..103.109
108
ATV Research Corp
105
Babylon Electronics
105
108
Command Productions
106
106
Digi -Key
107
Fair Radio Sales
103
Electronics
G.F.
IOI
107
H & R Electronics
107
103
1TM
Associates
102
108
Lakeside Industries
107
Radio
Leeds

Meshna Electronics, John Jr.

Polypaks
Solid State Sales
Southwest Technical Products
Southwest Technical Products
Surplus Center
Surplus Center
Sydmur Electronics

SLASHED

FACTORY FIRSTS

90

61

104
103
108

PRICES

SPECIAL SALE CB RADIO EQUIP'T

MEMORIES Semiconducters Free Flyer, UTI

POB 252, Waldwick, NJ 07463

DIODES

ea
ea
ea
ea
1N4OO6 -12 ea
1N4007 -15 ea

JAPANESE new products monthly! $1.00. Refundable. DEERE, 10639 Riverside, North Hollywood, CA

composition
1/4

Free catalog and price sheet. FORDHAM RADIO, 265 East 149th Street, Bronx, NY 10451

18KV 100 milliamp

(1N3055) $6.50 ea
Bonus gift for orders
of $5.00 or more

TUBE TESTERS MERCURY MODEL 204 Write:

BOB GREBER, 10144 Dunbarton Dr., EI Paso,
TX 79925

seg. fluorescent display tubes, LSI package for

logic, completely silent electronic operation.
Internal power supply operates clock up to 20 minutes
during power failures. Front set P.B. clock controls.

$19.95 Prepaid
Places transistor into actual
operation. Operates upon contact. Clear speaker tone
visual observations to make.
Tests transistors in or out of
the circuit. Money back guar antee.

-no

it

UNITED SALES. DEPT. 8690

BRIGHTWOOD, WASHINGTON, D.C. 20011

23-channel

SURPLUS

S139.95

ELECTRONICS

R- 388 /URR RADIO RECEIVER

550 RC
to 30.5 MHZ: 30 Bands -Used, Serviceable: $375.00;
Checked: $400.00
AN /URM -32 FRFRUENCY METER
125 KC
to 1000 MC In 3 Ranges -Used, Serviceable: $150.00;
Checked: $175.00
FR -4 /1.1 FREQUENCY METER
100 KHZ to
20 KHZ.
Used Serviceable: $ 85.00;
Checked: $110.00
FR -5 /U FREQUENCY METER
10 MHZ to
100 MHZ.
Used Serviceable: $ 80.00:
Checked: $105.00
FR -6 /1' FREQUENCY METER
100 MIIZ to
500 MHZ
Used Serviceable: $ 80.00;
Checked: $105.00
F R -38/U FREQUENCY METER & COUNTER

10

HZ to

10

MHZ -Used, Serviceable: $175.00:

-

With 525E Plug -In for

100 -220

Checked: $200.00

MHZ Extra:

50.00

Prices F.O.B. Lima, 0. -Dept. RE

SEND FOR BIG NEW CATALOG

$89.95

Rag. camas
$109.95

List Rice

23 -chanI ITEM M13- 870C -RE ) - - Professional

nel mobile CB transceiver with all crystals furnished.
Full legal ( 5 -watts ) power gives long range, dependable rodio communications with base station and other
mobile units. Very compact, easy to install in trucks,

autos, ATV's, etc. Mounting bracket furnished.

Latest design, solid state circuitry. Crystal controlled transmit receive frequencies and ceramic filter
provide sharp, clear reception over long range. Built in speaker. Microphone with coil cord and magnetic
hanger furnished. Jocks provided for microphone, ex.
ternal speaker and external antenna. 8'2 x 6" x 214
.

23- Channel, 5 -Watt, CB

Base Station Transceiver

FAIR. -RADIO SALES

1016 E, EUREKA

Box 1105'. LIMA, OHIO

Now Get MUSIC

ONLY FM

45802

Programs

...

Convert ANY FM TUNER to receive uninterrupted commercial free music being broadcast
by many stations.

'r
RIM

List

....... ......'

_
Limited Sale*

$99.90

Rag. Catalog

5149.95

$11111.90

ITEM #M13-891-RE I - Special savings on CB

Base Station Transceiver ideal for Contractors, Construction Co's., Road Builders, etc. Full legal power
( 5 -watts ) gives
you dependable rodio contact with
all your CB equipped vehicles in the field. Equipped
with crystals for all 23 CB channels, none extra to
buy! Latest design, solid state circuitry for trouble
free performance, long range, exceptional clarity.
(

Kit Only
New three transistor plus "Phase
locked loop" IC circuit gives you
$1450
perfect reception. No tuned cir- With Squelch
cuits, or critical adjustments. The
$1950
11/2" x 4" circuit board is powered from the tuner supply. +9 Wired & Tested
to 12 Volts DC @ 10 Ma. required.

$2500

With Squelch

Extender
Cable
Included
with
Tester

held

Hand

Limited Sole

Circle 107 on reader service card

CO

"IN CIRCUIT" -Model 85

Industries
PO BOX 413
TEWKSBURY MASS 01876

Wake up to music or tone. Compact size, beautifully

New $99.00
Prepaid U.S.A.
styled 115 V 60 cy.
EQUIPT cab. alum. blk, wrnkl. shock mtd for TS164/AR freq. mtr. 10'W x 7 %H x 11' 4'D overall. Hinged front door. Ideal for solid state devices.
New $7.95
Prepaid U.S.A.

TRANSISTOR TESTER

H & R

clock

LEEDS RADIO

23- Channel, 5 -Watt, CB

Mobile Transceiver

57RE WARREN ST. N.Y.C. N.Y. 10007

lbs.)

MAIL TO:

GOVERNMENT

DIGITAL CLOCK RADIO

15Ibs.)

FREE catalog New Electronic Devices! World's

Smallest Transmitter $19.95! Telephone Answerer $49.501 Telephone Recording Device
$19.95! "Bug" Detector $59.501 Many more!
SONIC DEVICES, 69-29R Queens Blvd., NY
11377.

FM /AM

a1

Nv

ITEM M13- 795 -RE

HIGH VOLTAGE DIODE

CAPACITORS: 75mfd,6V, Tantalum, 5/$1.00,

5,000/$550.; 1000mfd, 50V, 2/$1.00,
2,000/$600.; 2000mfd, 25V, 2/$1.00,
2,000/$600.; More; Free Flyer. OSBORN, Box
1191, Flagstaff, AZ 86001

d.N

transceiver has full legal ( 5 -watts power ) to give it

plenty of punch for reliable, long range communications. Has all the features and power of the larger
base mobile units. You can use these where you can't
get vehicles to go.
All 23 crystals are furnished. Isolated chassis
permits use in cars or trucks with 12 -volt system. Operates on 10 "AA" cells ( not furnished ) . Built -in
2'a" speaker /mike, 70" telescoping antenna, full controls. Jacks provided for external speaker, earphone,
external mike, antenna, power source, battery charger.
Carrying case with strap furnished. 10" x 3'," x 2'a"

watt 5%

10 for $1.00
specify low med or
high range of values

B & K, sencor test equipment, discount prices.

HIGH SCHOOL DIPLOMA for adults. Earn State

Diploma. Accepted by Civil Service, business,
colleges. Low cost. No tedious study. Money back guarantee. DETAILS: H -S PROGRAM,
Suite 2507, 1221 Avenue of Americas, New
York, NY 10020

$109.90

mixed values

IGNITION, 250: 1 Coil, Ballast $7.95. Free lists.

TRANSPARK, Carlisle, MA 01741

ELECTRONICS ENGINEERING &

INSTRUCTION

Reg. Catalog

$149.95

$99.95

DIO EQUIPMENT, P.O. Box 611, Fairfield, CT

06430

RENT Stereo tapes $1.50 week postpaid. Catalog 25 cents, TAPE LIBRARY, Box 8126, Washington, DC 20024

List Price

Limited Sale*

RESISTOR KITS

Powerful, 5 -Watt,
23- Channel, CB
Walkie- Talkie

741 70 ea

Crystals Supplied. Fully warranted. $99.95

check or M.O. (Information on request) CB RA-

RENT 4 -track open reel tapes -all major labels

3,000 different -free brochure. STEREO -PARTI,
55 St. James Drive, Santa Rosa, CA 95401

Nary, while supply is good!

LINEAR IC'S
709 35 ea

CB -SBE'S 23 channel mobile transceiver. All

TAPE & RECORDERS

SURPLUS
CENTER is offering Iola limited time only. Citizen's Brand radio equipment at a Very Special, Very Low price.
famous Brand Name

1N4001 -3
1N4003-60
1N4004-80
1N4005 -10

THE GREATEST R &R ALBUM two years in compilation. Available only thru mail. All songs released in original master form. 19 songs inc
Bopalena, House of Blue Lights, Strange Love
etc. All songs are collectors items and stylistic
landmarks in Rock and Roll. Send $5.00 to ALBUM P08 1301, Studio City, CA 91604

$2995
Plus postage
and m:urance

Free list of FM stations with SCA authorizations included. (List alone S .25)

THOUSANDS
SOLD

Operates on 110 -VAC, equipped with complete con-

trols; an -off-volume, illuminated channel selector, full

variable squelch, transmit/modulate indicator light.
Built-in 4'' o 2)5' dynamic speaker. Dynamic microphone with coil cord furnished. Jacks provided for
microphone, external speaker, external antenna. 11" o

7',"

v,r... -_

Southwest Technical Products Corp.

BOX

32040

SAN ANTONIO, TEXAS 78284

NOVEMBER 1972

www.americanradiohistory.com

4!; ". 110 Ibs.

All Items F.0.8. Lincoln, Near.

ii.

FIT

7,a.

filllig.

!i

Order Oireot From Ad.

Money Back 0

SURPLUS CENTER
pEPT RE -112,

LINCOLN, NEBR. 118501

RADIO- ELECTRONICS

107

AVIATION ELECTRONICS TECHNICIAN -Prepare for exciting career in new field of "Avionics". Train at nation's largest aeronautical
school. Indicate if eligible G. I. Benefits. SPARTAN AIRSCHOOL, International Airport, MN,
Tulsa, OK 74151

QUICK CASH
for Electronic EQUIPMENT,
COMPONENTS, unused TUBES. Send list now!
BARRY, 512 Broadway, New York, NY 10012,
212 Walker 5 -7000

TUBES -IEC 70% DISC. 5 FREE WITH EA. 50.

SENCORE, EICO, MALLORY, HEP, SHURE.

TUBES

RADIO and TV Tubes 364 each. One year guaranteed. Plus many unusual electronic bargains.
Free Catalog. CORNELL 4217 -E University, San
Diego, CA 92105

SHORTCUTS To Success! Highly Effective,

Profitable Short Courses. (75 Choices). Study At
Home. Diploma Awarded. Our 27th Year. Free
Literature. CIEE -E, Box 10634, Jackson, MS
39209.

RECEIVING & INDUSTRIAL TUBES, TRANSISTORS, All Brands -Biggest Discounts. Technicians, Hobbyists, Experimenters- Request
FREE Giant Catalog and SAVEI ZALYTRON,
469 Jericho Turnpike, Mineola, NY 11501

TV TUNER REPAIRS -Complete Course Details.

12 Repair Tricks. Many Plans. Two Lessons, all
for $1. Refundable. FRANK BOCEK, Qox 3236
(Enterprise), Redding, CA 96001

TUBES Receiving Factory Boxed, Low Prices,

Free Price List. TRANSLETERONIC INC. 1306
40th Street, Brooklyn, N.Y. 11218. Telephone
212- 633 -2800.

WANTED

SAVE money on parts and transmitting- receiving tubes, foreign -domestic. Send 25C for Giant

WANTED: Old radios, tubes -24, 47, 80's; pre

40's. M.E. SCOTT, M.D., Box 3608, Radford, VA

Catalog. Refunded first order. UNITED RADIO

COMPANY, 56-R Ferry Street, Newark, NJ
07105

24141

NEEDLES LOWEST

ALSO CARTRIDGES,

PRICES. FULL GUARANTEE. M & K ELEC.

DIST., 135-33 Northern BLVD., NYC 11354

XENON STROBELIGHT FLASHTUBES FT1 06

50W $2.50, 2/$4.00, 10/$16.00, 100/5125.00.

Plans 504. MINDLIGHT, P.O. Box 2846RE, Van

Nuys, CA 91404

lchnical Excellence
in Electronics.

On our small. friendly campus the emphasis is on Living as well

as Learning. Extra -curricular social activities. student clubs, a
student operated radio station. student government, new dormitory and a full sports program help provide a world of your own
In which to prepare for tomorrow. Associate Degree in Engineer-

ing Electronics. 13.8. obtainable. O.I. approved.

VALPARAISO TECHNICAL INSTITUTE

2N965
2N1605
2N2360
2N5324
2N1015D
2N2015
2N3584
2N3724
2N3772

regulator
$250
Power Design 3240, 1.32V at
4A power supplies
$95
Power Design 1210, 1 -12V at
l0A power supplies
$95
Dumont 304A scopes
$95
Tektronix 531 scopes with
B or K plug -ins
$475
$125
HP 521C counters
HP 400D voltmeters
$95
Ballantine 314 voltmeters
$95
Analog Devices regulated power supplies have been designed to provide
complementary power for Operational
Amplifiers, Function Modules, A -D

Price

10

UJT's

PROGRAMMABLE

similar to D13T with data

sheet
$.75
VARIABLE CAPACITANCE DIODES,
(similar to 1N5463A) used to tune
VHF, Color TV & FM broadcast
sets
$ 95
ER900 TRIGGER DIODES. These
biodirectional trigger diodes are one
of the best and cheapest methods to
trigger SCR's and triads ..4/$1.00
$ .65
FLV 100 Visible LED
$ 65
GaAs IR LED
MRD 148 photo
darlingtons
$ .65
2N3055 7 amp NPN silicon
power transistor 115 Vice
$1.00
6/$1.00
3/" reed relay

1N4886 25-40W
Power varactor

$4.95

10A

1A

100
200
300
400
500
*Press

e40

.70
.90
1.00
1.50

fit

Send

.70
1.10
1.35
1.60
2.00

15A

1.00
1.50
1.90
2.70
3.20

15

12

50

100

60

4.7
10

TANTULUM CAPACITORS
5/$1.00
MFD at 20V
4/$1.00
MFD at 20V
$ .50
MFD at 100V
MFD at 100V
S .75

2A

6A

200
.90 11.20
400 11.10 11.40
600 11.25 11.60
I

ITL IC SERIES

7400- .25
7401- .25
7402- .25
7404- .27
7410- .25
7413- .75
7420- .25
7430- .25
7440- .25
7441 -1.30
7447 -1.15
7450- .25
7460- .25
7472- .50
7473- .50

7474
7475
7476
7480
7481
7483
7486
7490
7492
7493
7495

--

.60
.80

--1.25
-1.20
--1.00

SOLID-STATE CAMERA eNK

Aloav able factory assembled
Ideal foe
experimenters, industry, o
High
etc.
quality performance backed by over seven years of
lob arel field testing
Fully Guaranteed
a
Completely
is to any TV
Con
a
nembly
without modification
Sal
E
y-to.fallee
manual
o Riedel ST-1A, eries D cm-

ucld

--

7410774121-

.57
.79
.80
.75

.75
.85
.55

74192 -1.92
8570 -1.50
8590 -1.50

3/51.00

14 Pin DIP sockets

16 Pin DIP sockets

60

MINIATURE TRIM POTS

500ohm, 10K, 20K, 25K

5 75 3/$2.00

50K

PRV

1A

3A

12A

100I.061.09I.24I
.07

200

.12

.20

50A

.90
1.25

400I.09I.16I.35I1.50
600
800
1000

.11

I
I

.15
.20

.20

I.28

.35

-7490

-7475

-7441

Special priced at $4.75

pm

will.
1149.40 PP onynene in USA F.
Cando /less vidicon tube $116.95:?)Mmy other
kits, ports and pl.s oleo available.
PHONO or WRITE for CATALOG...DIAL 402-987-3771

ATV Research

453 -RE

DAKOTA CITE NEAR. 68731

REBUILD YOUR OWN

PICTURE TUBES?
With Lakeside Inctries precision
equipment. yen can rebuild any
Dickure WWI

.. Il

For complete details. send tame,

address. sip code Lei

,I'Io
a

LAKESIDE INDUSTRIES

Fullerton Ave.

Miniature 7 segment cold

readouts
cathode neon

.$.50
709C operational Amp
741 operational Amp ....$.50
Amp
$1.00
Video
501
SE
.95
748 Adjust 741
$
$1.39
Dual
5.75
723 Regulator
TVR 2002 high power
.

$1.00

723

Silicon Control Rectifiers

20A 7011
6A 110A
PRV
.321
50 1.25
1

dolllas

1ilpi
i

'M EASY

YEATS

dolly

elan Model No.

'"n"

\\ AL

I1
FREE

a oowN
crams

iubaW

ii

ill.

sow

;111m,

kmeare

Yeats Appliance Dolly Sales Co.

.]

rii
%
a

1301 W. FOND DU LAC AVE

MILWAUKEE, WIS. 53205

F.C.C.

tli

.45
.75
300 .601 .90
400 .701 1.10
500 .80 1.25
600 1.90 1.40

1001.30
2001.50

'

and Second class licenses.

113

Dated

multiple

Schematic

Ability

for our fall catalog featuring Transistors and Rectifiers; 325 Elm St., Cambridge, Mass.

ALES
r1

Tel. (617) 547 -4005

www.americanradiohistory.com

choice

Includes Upand key

tests

PLUS - "Self -Study

agrees.
Test.' -- ONLY: 59.95 Postpaid

Ji

di

...

11010 010111811110 01511105

_e
.

84H
raar,w
Dose

NOW build your own

Capacitor

COMPAC
3

Frkr
r'want

P.O. 8 0 X 26348 E
SAN FRANCISCO, CALIF. 94126

COMMAND PRODUCTIONS

$3.00

r+D.a,
y

1.00 3.50
6.50
1.25
1.50
9.50
1.75
2.00
12.25 11.00

Postage. Average Wt. per package

1/2 lb. No. C.O.D.'s. Minimum Order

MAXNUAL!

Original Test -Answers cure manual

that prepares you at home for FCC First

.70 12.30
.90 12.75

Circle /08 on reader service card

NOVEMBER 1972
RADIO -ELECTRONICS

ts

LINEAR CIRCUITS

Terms: FOB Cambridge, Mass.

Send check or Money Order. Include

'

1.

appliance

$2.85

MG19F

YSATS

avow roues room,.

1.80

.50

self...I.da

MOVE

CONSISTING OF:
1 -NIXIE TUBE and SOCKET

.75

Somerville, Mass. 02143

108

RO%

NIXIE TUBES
Similar to Raytheon 8650
long life tubes, wtih socket
$2.25
& data sheet

DECADE
COUNTER KIT

Silicon Power Rectifiers

20A*
1.20
1.60
2.00
2.40
2.80

PRV

$18.95

200 PRV 15A full wave

rectifier 5.95

TRIACS
PRV

i-15

ONLY

Chicago. Ill. 60647

Phone: 312 -342 -3399

4.7

5.45
$.50

Full Wave Bridges

BUILD A 'SPACE -AGE "" TV CAMERAI!

3520 W.

NE 565 Phase lock loops $3.50

2N3819 FET
TIS43 UiT

.8
.8

SE 12 -60

$18.95 $26.95

30 $1.25
60 $.50
60 5.55

.2

30A
4A
4A

60V
40V
40V

SE904 SE902

Output Voltage (VDC)

Output Current (MA)

A. Converters and Digital

Logic. The supplies are completely
self contained. Epoxy encapsulation
provides properties close to a true
hermetic seal.

Consisting of 7 segment readout driven by 5 volts, having

5l," display, and a 7447 decoder and 7490 decade counter
$7.50

PNP
PNP
NPN
NPN
NPN
NPN
NPN
NPN
PNP

Model

D.

SEVEN SEGMENT
COUNTER KIT

.lA 300MHZ 40Hte 5 /51.00

7V
.15W
.lA 14MHZ 125 5/$1.00
.15W 24V
980
32 5.50
.06W 20V .05A
20
35 $1.50
60W 250V l0A
.025
10 $1.45
200V
7.5A
150W
26 $1.45
.012
150W 50V l0A
10
100 $1.50
2A
35W 250V
60 3/51.00
250
IA
.8W 30V

PNP 6E TO-18
NPN 6E T0-5

6E T0-33
6E TO-3
SI TO-82
SI TO-36
SI TO-66
SI TO-5
150W
SI T0-3
2N5296
SI TO-220 36W
36W
TO-220
2N6109
SI
Match pair push pull amplifier

Fine

and

Oat. G YatbenMne Trail, Vatparabo, banana 46393

TRANSISTOR SPECIALS

TEST EQUIPMENT SPECIALS

(used in good condition)
Tektronix 545A scopes with CA
$800
STABILINE
NE 15 KVA 95 -135V

as

Discharge
System for
little as $11.45!

Circuit diagram

^.

cluded with
-

in-

special

ignition transformer.
TR -200 transformer

6 or 12 volts
Complete COMPAC KIT
6 or 12 volts 25.95
(as described in

11.45

POPULAR ELECTRONICS-Nov. 1966)

all SYDMUR "CD" Systems.
SYDMUR -1268 E. 12 St..
Brooklyn, N.Y. 11230

FREE LITERATURE on

Southwest Technical Products

Catalog of Unique Kits
Tired of the some old projects? Ready for something new and different? Your free Southwest Technical Products catalog describes
olmost 50 of our unique reasonable priced kits. Save up to 50% over
the cost of comparable kits. Amplifiers, preamps, color organs, digital readout systems and more. Send for your free copy now.

Function
Generator

Digital
Microlab

Sine- Square
Pulse- Triangle
and Ramp Waveforms

logic

1.0 Hz to 1.0 MHz

The ideal way to check out your digital system designs,

or to learn how digital logic works. This versatile low
cost system contains four flip -flops, four gates, two buffers and three data switch system that can be used to
make up hundreds of experiments and basic logic circuits.
Indicator lights show the state at each output. Connect ions
are made with simple clip -on leads that are easy to attach
and remove. The instrument cannot be damaged by any
combination of external connections, no matter how wrong.
Connect more than one together for complex experiments.
Kit is complete with AC supply and wood grain finish outer
case. 10 x 7 x 3. Learn the basics of digital electronics by
yourself using our twenty -seven experiment lab manual written
for use with the Microlab.
Kit #DLM
4 lbs
$29.95
Microlab lab Manual
$ 1.95

Ask anyone who has been able to afford one. A function

generator is one of the handiest signal generators you can
own. You get five different waveforms that may be used
to test TV, radio, hi -fi, servo, digital logic and many
other systems. Output level is 2.5 Volts P-P maximum
at 70 Ohms source impedance. Choice of AC, or DC coupled output, with adjustable offset when DC coupled.
Plug together construction and three printed circuit boards make
construction easy. 51/4 x 6% x 21/2 impact plastic case. Get yours
now at our special low introductory price.
Kit #FG -1
3 lbs
$39.95

NEW

Digital Tachometer

400 to 9,990 RPM

4

Digit -LED Readout

Work with all 4,

Two Great Color Organs for your Holiday Decorations

cylinder engines
Something really difor 8

PSYCHEDELIA

ferent to add to your

car.
This beautiful
little instrument reads
out your engine RPM
directly on a bright red light emitting diode display. Phase
locked loop circuit makes possible a four digit readout
that is accurate to 2 %.
Plug together construction simplifies construction. Only +12
Volts and distributor point connections required on the engine.
41/2 x 21/2 x 7 black vinyl covered metal case.
Kit # TACH -1
3 0 lbs
$79.50

Short Proof
Power Supply
-32 Volts
Dual Meters
0

0 -2

Amps

Continuous adjustment of voltage and current. Regulated

low ripple output. Compare the voltage and current output
with others at twice our low price.
Brushed gold front panel, black vinyl covered metal case. 9 x 7 x
Kit #143
8 lbs
$39.50

Tel

and now PSYCHEDELIA II

The best color organs available. Both of these unique
color organ systems have four channel output. You can
use up to 750 Watts of lamps per channel for a total of
over 2.5 Kilowatts of light from each color organ circuit.
Transformer isolated inputs can be safely driven from
any sound system, or stereo system speaker connection.
Psychedelia is a filter type color organ, using the "classical"
and amplitude detector system to generate four channels.
Op -amp active filters are used in our circuit along with our exclusive ramp triggering system to give fast proportional light
response. Automatic level control allows the circuit to corn pensate for up to 40 dB variation in sound system level without
any need to readjust the color organ sensitivity.
Psychedelia Il is a digital color organ. This new and different
approach to color organ design uses a sampling system and
counting techniques to separate the sound input into four light
channels. This type system tends to produce a very active
flashing type display which many prefer. It also is more random and does not follow the music in quite os obvious o way
os a filter type color organ.
Kit #QX -1 or QX -11
4 lbs.
$44.95
Both kits less display of any kind.
Bookshelf display semikit
$26.50
I

filter

SOUTHWEST TECHNICAL PRODUCTS CORPORATION

219 W. RHAPSODY, SAN ANTONIO, TEXAS 18216
Circle 109 on reader.service card
NOVEMBER 1972

www.americanradiohistory.com

RADIO -ELECTRONICS

109

LIVE IN THE WORLD OF TOMORROW...TODAY!

(And our FREE CATALOG is packed with exciting and
unusual ecological & physical science items -plus
4,000 finds for fun, study or profit ... for every member of the family.)

M.

111111

low

MIR

NE"

FLEXIBLE IMAGE
TRANSMITTER

ELECTRONIC D IGITAL
COMPUTER KIT

...

1.

subject to infinity.

Ideal for monitoring

hazardous processes, surveillance instrument, demonstrate fiber optics. Over 4,000
coherent glass fibers (.002 "), a/e" diamepiiister
semi -rigid gooseneck sheathing.
Stock No. 60 ,857EN .... S40.00 Ppd.

i 4")

(11 it 12+

MO 111111 1111.11

power

Detects your "find" sharply with "sound -

Stock No. 60.175EH

$39.95 Ppd.

TAPE -SLIDE SYNCHRONIZER

11111.

Coordinate tape recordings with

$9950

terrific American -made value w, big

slide series. Hook up stereo recorder

to remote control projector and TSS
-then record what you wish for each
slide. Playback and TSS AUTOMATICALLY changes slides in synch. w/
tape. Your presentation "gives itself". Perfect for sales meetings,
lectures, and "talking albums" of
child's growth -add new dimension
. anywhere.
to vacations, parties .
Stock No. 41,222EH
$21.95 Ppd.
6' CONNECTOR CORDS, $4.50 Ppd. ea.
Kodak Projector (#60,804E11)
Airequipt(#60,805EH)
Monaural Tape Slide Synchronizer

ma-

chine capabilities. Add, subtract, multiply, divide, do mixed calculations

silent answers in milli- seconds. 8digit entry and readout w /16 -digit
cap. Auto. precise to the decimal.
Also features fixed decimal, constant key underflow, zero suppression, minus signal for true
credit balance, error correction, keyboard roll over memory. Solid state: modular
constr., only 3 -lb. Year
guarantee normal use).

No. 76,000EH (61/2x9x2" Hi)

loss.

off" loudspeaker. Comes ready to go. One tuner control;

all transistor; adjust. stem; perfect balance. Includes 9v
battery, FREE TREASURE GUIDE To 101 Treasure Sites.

bleed fuel

lines, check leaks, etc. Lifts 40 lbs.

with included "T" lifter (21/2" diameter
much more with larger cup.
cup)
Stock No. 71,301EH
$12.00 Ppd
$5.50 Ppd
Stock No. 71.300EN
(without gauge /lifter)

ELECTRONIC CALCULATOR

FINDER

Best, easiest to use solid state

metal detector at its price. U. S. made!
Only 3 lbs. 6" search head detects
penny at depth of 5 ", silver dollar at 8 ",
bag of coins at 18 ". Easily works thru dirt,
3..%
sand, wood, water (30" deep) and rock with no

N`INS MI

, TREASURE

,.

Nothing like it! Top -quality hand -held

pump produces and maintains 25" of
vacuum. Has instant release tab, 15/8''
diameter stainless gauge (0-30"). 100'.s
siphon noxious fluids, evacuof uses
ate bell jars and castings, clean, retrieve, lift sterile objects, demonstrate

Magdeburg hemispheres,

FEATHERWEIGHT

a!-

FIRST LOW -COST

VACUUM PUMP!

$50.95 Ppd.

Stock No. 71,701EH

$99.50 Ppd.

TODAY!

COMPLETE AND MAIL

MAIL COUPON FOR

ORDER

GIANT FREE
CATALOG!

EDMUND SCIENTIFIC COMPANY

300 Edscorp Building, Barrington, N.J. 08007
How Many

Total

Price Each

Description

Stock No.

MORE THAN

4000 UNUSUAL BARGAINS!

Completely new Catalog. Packed with huge selection
of telescopes, microscopes, binoculars, magnets, magnifiers, prisms, photo components, ecology and Unique
Lighting items, parts, kits, accessories
many hard to-get surplus bargains. 100's of charts, illustrations.
For hobbyists, experimenters, schools, industry

PLEASE SEND

GIANT FREE CATALOG

TOTAL $

" EH"

EDMUND SCIENTIFIC CO.

300 Edscorp Building, Barrington, N.

1.

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Please rush Free Giant Catalog "EH "

check
enclose
money order for

30 DAY
MONEY -BALK

Name

NAME

YOU MUST BE SAMISFIED

OR RETURN AN{ PURCHASE IN 30 DAYS
FOR FULL REFUND

City

ADDRESS

CITY

Zi=
11=111

110

GUARANTEE

Address

RADIO -ELECTRONICS

about computer programming

logic,
decimal, binary systems, Laws of Sets.
Even do your own programming after
completing the simplified, 116 -page
Instruction booklet. Circuits are eas- /
IN changed, readout Is from an
Illuminated control panel. Requires
2 "D" batteries (not incl.)
Stock No. 71,434E11 ..$31.50 Ppd.

mtew

164 PAGES

oft

Solve problems, play games, predict weather,

even play miniature chess, with this actual working model of giant electronic
brains. Amazing new fun way to learn all

Hi- resolution image- transmitter lets you

see into remote, inaccessible illuminated
areas; through pipes, tubes or any 4" +
op
no
r ho
intricate. Provides
clear, wide sigathting. 7 X magnifying eyepiece focuses from less than 1/2" from

lift MN

MIMI

'MN

Circle 96 on reader service card

NOVEMBER 1972

www.americanradiohistory.com

STATE

ZIP

111111

Leader

Multiplex/Stereo
Generator

WITH STABILITY
LIKE THIS,
WHAT ELSE
DO YOU
NEED?
Check multiplex alignment, balance and separation with "never
before stability "! The LSG -231
is so precise, so accurate, you
may not want to use a scope!
That's because this compact,
easy -to- operate, Multiplex /Stereo
Generator has an audio signal
frequency of KHz, with 1%
accuracy, and 50dB signalseparation. The 19KHz pilot signal
frequency has - 2Hz accuracy.
Output voltage is 0 to 3Vrms
(cont. variable).
Whether you use it in the field,
on the bench, or in a lab, this
is the generator with all the
features you want for fast, easy
service of all multiplex receivers
and tuners. Complete with handy
tilt- stand, it's another reliable,
rugged instrument from Leader.

LSG -231
$229.95

Loader

The more you see ...

the more you believe.

INSTRUMENTS CORP.

37

27 Twenty- Seventh Street,

Long Island City, N.Y. 11101

(212) 729 -7410

Circle 97 on reader service card

www.americanradiohistory.com

FROM WINEGARDIUI.THE GREATEST

BROADBANDAMPLIFIER VALUE EVER!
Winegard
Ultrapiex
Modular
Broadband

Amplifies
with
Highest
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and
Output
Capability.

111.110.44.0
nsx-a

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Z11E4AR0 tO:PAM!
69(9LIOA,

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WINEGARD
ULTRA -PLX

TV

MOCEt

PM

O4t8t80

o,smigunom SKIM
MOIL DSX.11A

82 CHANNEL
BROAU3ANO
TV AMPL FIER

* 5 models with unlimited

flexibility
* VHF, UHF or any combination

* sub -channel and closed

circuit optional
* electronically regulated and filtered
power supply with heavy duty transformer

Now you can install a higher- performance

system for sharper - much sharper - MATV
pictures! Check your distributor or write
Winegard.

* choice of single or separate band

antennas, plus switch -selectable FM

trap on 3 largest models
* modular boosters available for 15 db
additional gain in weak signal areas

WINEGARD

TELEVISION SYSTEMS

Winegard Company, 3000 Kirkwood Street, Burlington, Iowa 52601

Circle 98 on reader service card

www.americanradiohistory.com