Multiple Choice Questions

for Laboratory Experiments

--

1. Design and measure the frequency response of an RC coupled amplifier using

discrete components.
2

ioup,ed amp,,fler and

rdtrc
JKI

dete,ne

<*

Which capacitors assists in preventing the loss of gain due to negative feedback
without affecting the DC stability of R-C coupled amplifier ?
|bj Bypass capacitors (CE)
aj Coupling capacitors (Cc)
S c] Both a and b
j d j None of the above
[An*. : b]

Q.1

The rate of -20 dB/decade is almost equivalent to

[b] 6 dB/octave
aj - 4 dB/octave
[id] 10 dB/octave
[c] - 8 dB/octave
Q.2

[Ans. : b]

Which region/s in frequency response curve of an amplifier maintains the constant

level of gain ?
[bj Mid Frequency Region
| a! Low Frequency Region
[Ans. : b]
fd] All of the above
|c ] High Frequency Region
Q.3

CM
frequencies are values of frequency at which the RC circuits reduce the
vltage gain to 70.7 % of its midrange value.
[Ans. : d]
jc] Comer [d] All of the above
Critical
[bj Cutoff

til

F. Determine the
An amplifier has an Rin = 1.2 k. The coupling capacitor is 1
approximate lower cut off frequency.
[Ans. : a]
133 kHz
kHz
13.3
[c]
kHz
133 Hz
133
[b]
Q.5

a lower cut-off frequency of

A certain amplifier has a bandwidth of 22.5 kHz with
Hz. What is the value of higher cut-off frequency?
[Ans. : c]
jb! 225 kHz [cj 23.1kHz [dj 21.9 kHz
600 Hz

Scanned by CamScanner

4\

r
MCQ for Lab

1-2

Analog Electronics

Expehm

An amplifier has an input signal voltage of 0.054 mV. The output voltage is 12.5 V
The voltage gain in dB is
.
Q.7

0 53.6 dB
Q.8

[a]

[b]

107.3 dB

231 dB

[d]

116 dB

A ten-times change in frequency is called a(n)

octave
[b] decade
none of the above
decimal

[Ans. : b]

[Ans. : b]

Q.9

A three stage RC coupled amplifier uses identical stages with cut-off frequencies
fj = 100 Hz and f2 = 500 kHz. The overall cut off frequencies f and fHpj will be
and

0 100 Hz, 500 kHz

0 196 Hz, 255 kHz

0 300 Hz, 1500 kHz

0 None of these

[Ans. : c]

Study the effect of voltage series, current series, voltage shunt and current shunt
feedback on amplifier using discrete components.

3.
Q.10

Open-loop gain and loop gain of an amplifier is given by.

0A,AP
none of the above
[b] Aft A
ft A

_
0
0
0
feedback amplifier, voltage sampling_.

Q.11 In a feedback

0 AP

.
amplifier, sensitivity D is equal to
1/(Ap+l)
1 + A0
1-A3

[Ans.: a]

[Ans.: c]

Q.12 In a negative

|aj

tends to decrease the output resistance

tends to increase to output resistance

0
0 does not alter the output resistance

[dj produces the same effect on output resistance as current sampling

[Ans : a]

.
amplifier, current sampling
[a] tends to increase the output resistance
tends to decrease the output resistance
does not alter file output resistance
[dj produces the same effect on input resistance as voltage sampling

[Ans. : a]

Q.13 In a negative feedback

0
0

Q.14 In a negative feedback amplifier, series mixing

j a~|
j b]

tends to increase the input resistance

tends to decrease the input resistance
[ c j does not alter the input resistance
produces the same effect on input resistance as shunt mixing

Scanned by CamScanner

[Ans. : a]

'

' 4

/mel9

Electronic8

L-3

a neatiVe fmiback a>PUfier,

shunt mixmg
the
increase
to
input resistance
tends
tends to decrease the input resistance

Q.15

|a]

g]

!c| does not alter the input resistance

Pfduces *e same effect input resistance as

@j

"

MCQ for Lab Experiments

the series mixing

[Ans. : b]

Q.16 Negative feedback in an amplifier improves

l a j the signal to noise ratio at the output

03 reduces distortion

[c j both (a) and (b)

I d| none of the above

[Ans. : c]

Q.17 For a shunt-shunt negative feedback amplifier

fa] input impedance decreases but output impedance iincreases

f b] both input impedance and output impedance increases
Q both input impedance and output impedance decreases
[dj none of the above

[Ans. : c]

Q.18 An amplifier with the negative

feedback.
[b] reduces the noise

[a] controls the gain

[cj reduces phase distortion
Q.19 When negative

[aj is increased [b]

[d]

[Ans. : d]

all of the above

voltage feedback is applied to an amplifier, its voltage gain

is reduced [c] remains the same [d] none of the above [Ans. : b]

feedback fraction is always

more than 1 [c equal to 1 [d] none of the above

Q.20 The value of negative

[a] less than 1 jlbj

[Ans. : a]

to the
output of an amplifier is 10 V and 100 mV from the output is fed back
input, then feedback fraction is -

Q.21 If fte

B 0 001

0.01

a
0
0.!

[Ans. : a]

0.22 The gain of an amplifier without feedback is 100 db. If a negative feedback
is applied, the gain of the amplifier will become

5 db

[bj

300 db

103 db

[d]

97 db

gam
Q.23 The gain of an amplifier with feedback is known as
none of the above
closed loop
open loop
resonant

Q;24

--0

Negative feedback is employed in

oscillators [b] rectifiers |7| amplifiers

Scanned by CamScanner

..M

none of the above

ihmef fhr knowfedQB

of 3 db

[Ans. : d]

[Ans. : c]

[Ans. : cj

MCQ for Lab

L-4

Analog Electronics

Q.25 When a negative voltage

[ a]

is increased

[cl

remains the same

to an amplifier, its

applied
[b] is decreased
[ d ] insufficient data

feedback

is

bandwidth

________

Experim

IAn*. : aj

amplifier using 741

Design and realize inverting, non-inverting and buffer

4.

..
.
.....

op-amps.

negative feedback is provided by connecting

terminal.
between output and
[a] noninverting jb] inverting [cj ground dj none of these
Q.26 In closed loop mode, the

mode.
In most of the applications the op-amp is used in
open loop [b] saturated [c| dosed loop[d| none of these

resistance
[An*. : b]

Q.27

[a]

[Ans. : C]

following statement is true for the concept of virtual ground ?

j a I Both input terminals carry equal current.
[b| Both input terminals are directly grounded.
[c] Both input terminals are at same potential.
[dj None of these
[Ana. : c]
Q.28 Which of the

Q.29

[a]
[~cj

is a linear op-amp application.

[ b] Zero crossing detector

f d] None of these

Comparator
Voltage follower

[Ans. : c]

Q.30 The phase shift between input and

[b]

180

output in an inverting amplifier is

90
[d| 270

Q.31 The gain of the inverting amplifier using

0 -10

-11

0 10

[Ans. : b]

= 10 k2 and Ri = 1 kQ is
[0 11

Rf

[Ans. : a]

Q.32

0
[ c]

In an inverting amplifier if gain is one then the

circuit is called
Schmitt trigger
[b] summer
phase inverter
[d] rectifier

[Ans. : c]

Q.33

( a]

Which of the following circuit is used as

a scale changer ?
Schmitt trigger
Averting amplifier
Phase shifter

0
0 Noninverting integrator

[Ans. : b]
TECHNICAL PUBLICATIONS\

Scanned by CamScanner

AnuP bailor knowledge

L-5

MCQ for Lab Experiments

@'6V

-16V

B - 12 V

jdj

-18 V

Q.J5 The phase shift between input and output in a

noninverting amplifier is
[b] 180
9*
[d| 270

0*

Q.36 The gain of the noninverting amplifier using R,

= 10 kQ and Ri

[a] "10

0 -ii

0 10

-[b]

Q.37 The closed loop gain of

0 inverting amplifier
@

[Ans. : d]

amplifier.

[b]

[Ans. : b]

= 2 k2 hence its R* =
21ka

amplifier gain is 21 and it uses Ri

0 4OkQ 0

20 k2

of the voltage follower is

negative
[b] infinite

0 unity

Q41 The voltage follower has

[Ans. : b]

CM2 The voltage follower is practically used to

0 increasing efficiency
reducing loading effect
0 none of these
reducing offset error

0
0

043 The feedback factor P of the voltage follower circuit is

Q-44 An OP-AMP

adder

[b]

[Ans. : d]

property.

HI all the above

large output resistance

0i

[Ans. : c]

fbj large input resistance

0 small bandwidth

that of a inverting

greater than
fd] none of these

Q.39 An noninverting

0 zero

[Ans. : b]

[b]

0 equal to

Q.40 The gain

= 1 k2 is

aa

Q.38 The input resistance of noninverting amplifier is

[a] less than

[An#. : c]

[Ans. : a]

circuit fe always greater than 1.

noninverting amplifier
[d] none of these

voltage follower

0 10.5 kQ

[c]

greater than 1

[d] less than 1

and output terminal

shorted between inverting terminal
voltage follower

[c]

integrator

TECHNICAL PUBLICATIONS

Scanned by CamScanner

[d|

inverter

An up thrust for knowledge

[Ans. : a]

[Ans. : a]

is

called

[Ans. : b]

Analog Electronics

Q.45 When

the

MCQforLabExpenrmM,

L-6

non-inverting amplifier, the input signal is

an Op-Amp is used as a
a resistor.
input is grounded through
input and die

___

[b] inverting, non-inverting

(d] inverting, inverting

a j non-inverting, inverting
[cl noninverting, noninverting

[Ans. : a]

using op amp IC 741 and show that

Verify the operation of a differentiator circuit
_
it acts as a high pass filter.

s.

Q.46 If input to an differentiator using

R = 100 k2 and C

output equation is
[a] o) cos cot
[cj -100 o) cos cot

none of these

fbj + co cos cot

[d]

If we apply a sine wave to a differentiator, then we get

fb] negative cosine wave
[aj cosine wave
[d] triangular
[cj sine wave
Q.48

If we apply a square waveform to a differentiator, then we get

cosine wave
[b] negative cosine wave

j d]

ramp

train of impulses

Q.49 In an inverting

ideal differentiator a

[a]

resistor

diode

Q.50

[c]

capacitor

[aj high pass

Q.52 A

[b]
[bj

[c]

square

Q.53

at its output.
[Ans. : d]

[Ans. : b]

[Ans. : c]

[dj

low pass
[Ans. : a]

id] trianglular

An output of a differentiator is
proportional to
input phase
RC time cocnstat
input amplitude
E] input freqauency

Scanned by CamScanner

[Ans. : b]

filter.

band reject [cj bandpass

sawtooth

at its output.

inductor

differentiator converts linear ramp into

j a] constant d.c.

[aj
[cj

[d]

E R1Cf J
El ciRf%

differentiator acts as a

[Ans. : a]

is connected in the feedback path.

The expression for output voltage of differentiatior is

i
d + C
- 1 V|n dt+C

Q.51 A

0.1 pF is 100 sin t then the

Q.47

[aj
[cj

[Ans. : a]

TFr.HMir.Al

f># I <31

|/h aw-M.

[Ans. : M

L-7

MCQ for Lab Experiments

the paiK f-'

l'o op-an.p differentiator
OM Match
Input

Step

Square wave

3.

Sine

Output

1-

Train of impulses

2.

Impulse

3.

Cosine

0 W' 2'2' 3-3 13' 22' M 0 '-2. 2-1, 3-3 [dl None of these
the operaHot. of a integrator clrc|Ilt
uslng p amp

Q.55

m and show that ft acts

is used in analog computers.

[a] Differentiator
[c] Integrator

[b"| Summer
[d] None of these

[Ans. : c]

Q.56 If we

[c]

[An*. : c]

apply a sine wave to an integrator, then we get

cosine wave
negative cosine wave
sine wave
[dj triangular

at its output

we apply a step waveform to an integrator, then we get

jbj negative cosine wave
cosine wave

Q.57 If

[aj
@ ramP

[dj

[Ans. : a]

at its output
[Ans. : c]

sine wave

integrator.
op-amp is called
[c] hybrid id] composite

Q.58 The integrator not using an

[a] active

jb]

passive

an op-amp is called
passive [c] hybrid

Q.59 The integrator using

0 active

[b]

_
[dj

[Ans. : b]

integrator.

composite

[Ans. : 4

is connected in the feedback path.

In an inverting ideal integrator a
diode
[bj resistor [c] capacitor [d] inductor
[Ans. : c]

Q.60

Q-61 At the

0 10 Hz

[b]

frequency, gain of an integrator is maximum.

[dj 0 Hz;
jc] fH
infinite

[Ans. : d]

<5.62 The expression for output voltage of an inverting integrator is

0 RJ Via d+ C

0 -Rrl V *+C

0ciRfTT
knowledge
TECHNICAL PUBLICATIONS'"- An up thrust for

Scanned by CamScanner

[Ans. : b]

L-0

Analog Electronics

MCQ for Lab

Ex

pure d.c. input, the integrator output is

zero
triangular
ramp
[d] cannot be decided

fWrnonto

Q.63 For a

[aj
|c]

lAna. : cj

Q.64 An

[a]

filter.
integrator acts as a
high pass
[bj band reject [c] bandpass

Q.65 The time

[d|

Q.66 Match the pairs for an

0%

@1 R,Cr

[Ans. ; tq

op-amp integrator.
Output

Input
1.

Step

1.

Triangular

2.

Sine

2.

Ramp

3.

Square wave

3.

Cosine

[a] 1-1, 2-2, 3-3

[bj 1-2, 2-3, 3-1

[d] None of these

0 1-3, 2-2, 3-1

[Ans. : b]

Design & Verify the operation of adder and subtractor circuit using op amp 741.

Q.67 The expression for the

[R!

R2

Vz]

output in 2

0
Q.68

VQ

[Ans. : aj

constant of an op-amp_integrator is

7.

low pass

inut inverting summing amplifier is

Rt Vl r2 v*
+

none of these

In an inverting summing amplifier with 2 inputs if

=-

0 -V, +V2

0 - (V, + V2) 0

Vj -V2

Q.69 An

[d| none of

inverting summing amplifier uses

V.
Vi =V2 =1 V then its output is
4V
-2V
-4 V

Q.70 The

zero.

[Ans. : a]

these

R1=R2=lkft

0 +2V

phase difference between input and output for

fa]

inverting

[c]

unity gain

[bj non-inverting
[d] none of these
TECHNICAL PUBLICATIONS

Scanned by CamScanner

- An up thmst

R1 =R2 =Rf

=R then
[Ans. : b]

and

Rf

=2k> with

[Ans. : c]

summing amplifier is

[Ans. : bl

for knowledge

L-9

**
Rf*

***. ifRi =Rz =RJ _R

0R

MCQ for Lab Experiments

4R

0 3R

[dj

In a 2 input non-inverting amplifier, if R,

a72

SR

_-

0 3R

to4~72+Vg

2R
[Ans. : d]

=R2 =R then Vc =V, +V, if R. =

jdj

2R

[Ans. a]

circuit is used as an average circuit.

Q.T3
lay Inverting summer
Non-inverting summer

0
0 Buffer amplifier

uTj Integrator
Q.74 For an average

circuit Rx =R2

0f

Rn =R then Rf =

Hi @4

Q.75 A differential

[a]

amplifier amplifies the

addition
[b] subtraction
multiplication
[d] division

[Ans. : b]

between two input signals.

[Ans. : b]

0.76 An average circuit has 5 inputs then the ratio of Rfto R is

10
5
1
0.2

[Ans. : a]

[Ans. : d]

8. Plot frequency response of AC coupled amplifier using op amp 741 and study the
effect of negative feedback on the bandwidth and gain of the amplifier.

0.77 The closed loop gain of practical inverting amplifier is

0-Ri + RfA+OLAOLRI

Rf
0-Rl + AOL
Rf + AQLRI

a - RlApL(Ri+Rf)
+ Rf + AOLRl

Rf
IS-Ri + AOL
+
Rf A0lri

[Ans. : b]

0 78 The closed loop gain of practical noninverting amplifier is

....

+ AOL
R1 Rf + AOLRl

\r\

AOLRf
Ri + Rf + AOLRi

+ Rf)
PI 4.-AOL(Rl
Rl + Rf+AOLRl

nn

A OL Rf
R1 + Rf + A0LRi

j.

"

IP

Scanned by CamScanner

AM

tin

fhmcf fr\r IrtVUu/cwirM

[Ans. : c]

MCQ for Lab ExperUne

L- 10

Analog Electronics

loop inverting
closed
of
bandwidth
Q.79 The
configuration.
compared to its open loop

[b] 1+ AOL

0A?
f

a I+AOLB

AOL

cj

amplifier increases by the factor

- as

B
noninverting amplifier increases by the factor
Q.80 The bandwiidtt, of closed loop
compared to its open loop configuration.
1 + AOL

Rx1
A0L

El

g 1 + AOL
B

0I+AOLB

Q.81 The

open loop bandwidth of op-amp is

[Ans. : d]

[Ans. : c]

0 3dBto/o 0 idBto /o0 OHzto/0 [1 Noneofthese

Q.82 If operating frequency of op-amp varies then its [a]
[cj

both gain and phase angle varies[b] only gain varies

[ d] both gain and phase angle remain constant
only phase angle varies
[Ans. : a]

_.

Q.83 The

called

graph of variations in gain and phase angle of op-amp against frequency is

[b] frequency response

[dj frequency stability response

[a] transient response

[cj switching resposne
Q.84 In the frequency

[Ans. : b]

response of op-amp, the frequency scale is

[a] antilogarithmic
[cj linear

El exponential
GQ

logarithmic

Q.85 The frequency at which the gain

[a]
[cj

___

[Ans. :

comer frequency

of the op-amp is unity is called

[b] unity gain bandwidth

break frequency

0 none of these

--

[Ans. : d]

[Ans. : b]

9. Study of IC 555 as astable and monostable

multivibrator.
Q.86

HI *

The IC 555 timer has

16

pins.

til

TPrnMini

Scanned by CamScanner

0 24

[Ans.: cl

L-11

Ofi

** threShld *""*r ftan 3V

[b] zero

Q.8S For
high

[c]

MCQ for Lab Experiments

output of IC 555 to

low

[dj

infinite

less 1111111 I Vcc / *be output of

IC 555 is
3

triK8er

zero

c low

__

[An*. : c]

[dj infinite
[An*. : a]

Q.89 The charging time constant in IC 555 used as an oscillator is

[a] (RA +2RB)C

0 (RA+RB)C

a RC

@2(RA+RB)C

[An*. : b]

Q.90 The discharging time constant in IC 555 used as an oscillator is

@ (RA + 2Rb)c
(RA +Rb)C

[cj 2(Ra +RB)C

@ RBC

[An*. : d]

Q.91 The total time period of IC 555 as an oscillator is

|aj (RA +2Rb)C

@ 2(Ra +Rb)C
Q.92 The

duty cycle is defined as

0?

0w
Q.93 The

(7
L

0 (RA+RB)c
0 RbC

[An*. : c]

duty cycle of IC 555 timer as an oscillator is

2a+r B

RA+2RB

RA + 2RB
RA +RB

Q.94 The frequency of

+ 2Rb)
u fl*A1.44 C

RA + RB
2RA +RB

RA +2RB
[An*. : a]

Hz.

1.44

(RA+2RB)C
[dj none of these

0 (2RA1.44
+Rb)C
Q.95 IC 555 time

oscillator of IC 555 timer is

FT)

used as an astable multivibrator uses RA

[An*. : b]

= 5 kQ,

and C = 1 |iF then its frequency is- Hz.

none of these
4.86 x 10s
4.86 x10s [Bj 205.714

RB = lkQ

[An*. : a]

Q.96 In IC 555 used as

+
to
.

[An*. : b]

monostable multivibrator, pin 4 is connected to pin 8 and both to

VCC
l?j adjust the time period

[b| to increase the duty cycle

TECHNICAL PUBLICATIONS' An up thnjst for knowledge

Scanned by CamScanner

Analog

Electronics

cycle
to decrease the duty

(cl

monostable multivibrator

Q.97 In

[dj

to avoid the

using 555, the

fb]

i
trigger voltage is greater than Vcc

0
[c]

__-

MCQ for Lab Experiment*

L- 12

trigger voltage is greater than

monostable multivibrator

Q.98 In

[a]

[An*. : d]

circuit state remains unchanged till

1
trigger voltage is less than -

Vcc

[An*. : a]

fdj none of these

Vcc

55
ecc, the circuit returns to low state

using

when

|b] threshold becomes greater than Vcc

Vcc
threshold becomes greater than Vcc
threshold becomes less than

accedental reset

threshold becomes less than

Vcc
[An*. : b]

pulse width of monostable multivibrator is given by

1.38 RC
1.1 RC
RC
0.69 RC

Q.99 The

Q.100 For R

0 5 msec

= 454.54 kQ and C = 10 pF,

5 nsec

the pulse width of monostable multivibrator is

0 5 nsec 0 5 sec

a pulse width of 15 sec and R =136.363 k2 the C

multivibrator.
0.1 nF
100 pF
1 pF
100 pF
Q.101 For

[Ans. : c]

[Ans. : d]

in a monostable
[Ans. : c]

Q.102 For

a time delay of 1 sec and C =10 pF, the resistance R required in monostable
multivibrator is

0 91 kfl

0 9.1 kQ

0 91 Q 0 910 Q

[Ans. : a]

10. Design & realize using op amp 741, wien-bridge

oscillator
Q-103 An

oscillator differs from an amplifier because it

has more power
requires no input signal
requires a feedback
none of

0
0

these

J
[Ans. : b]

Q-104The

0 A3
0 A0
LCj

A0
A0

Barkhausen condition for oscillators

states that
= 0, phase shift around a loop = 180
= 1, phase shift around a loop = 180
* 1, phase shift around a
loop = 360
0,
= phase shift around a loop 360

Scanned by CamScanner

Anu'>*tforkt

[Ans. : d

L- 13

Wien bridge oscillator, the op-amp is used in

0.105

ja|

r-.
noninverting jbj inverting

Q l06ln

0180

MCQ for Lab Experiments

[c]

open loop

[dj

mode.

none of these

a Wien bridge oscillator, the feedback contributes

[bj 90
[c] 270
o

[Ans. : a]

- phase shift.
[Ans. : d]

Q.107 In a Wien bridge oscillator, the forward path contributes - phase shift.

0 270

90

0 180

[Ans. : a]

Q.108The gain of the op-amp circuit used in a Wien bridge oscillator must be greater
.
than or equal to
2
[Ans. : c]
3
9

0V3

frequency of oscillations of a Wien bridge oscillator using equal resistances and

.
equal capacitances is given by
Q.109 The

2JIRCV6

1
2rcRC

[dj

Q.110 A wien bridge oscillator uses

[c]

both

[a] positive

jb]

negative

Q.111 If registance value in

None of these

[Ans. : b]

type of feedback.

fd]

none of these

[Ans. : e]

frequency sensitive arm of a Wien bridge osdllater decreases,

the frequency

[a] increases

[b]

decreases

[c]

remains constant

Q.112A Wien bridge oscillator uses R

0 15-91

[b]

0.1591

Scanned by CamScanner

[dj none of these.

= 10 kft and C =

0 1591

11-591

[Ans. : a]

0.01 pF then its frequency is

[Ans. : d]