For full-wave rectified sine wave, rms value is

0.707 im

0.6036 im
0.5 im

0.318 im

Ripple factor of full wave rectifier

Ripple factor of full wave rectifier

It has dynamic resistance

. The value of the resistance is the inverse of the slope of the i-v characteristics of the Zener
diode

All of these

Which of the following eliminates fluctuation in the rectified voltage and produces smooth dc :

ransformer

rectifier

regulator

filter
Which of the items below describes an RF amplifier which will amplify a weak signal voltage in
relatively the same proportion as it will amplify a stronger signal voltage?

Class A amplifier

Linear amplifier

Non-linear amplifier

Ritarted amplifier

Inverting amplifier

How many AND gates are required to realize Y = CD + EF + G?

1

2
3
4

Both transistors either NPN or PNP, in the multivibrator are biased for linear operation and are
operated as Common Emitter Amplifiers with…….. positive feedback.

80%

90%

100%

33%

Which of the following is provided by a CB transistor amplifier?

Voltage gain
Power gain

Current gain

Gain stability

Registration No *

bsf1701928

The output voltage waveform of the given circuit will be

Option 1

Option 2

Option 3
 Option 4

The voltage gain of a common collector configuration is

Unity
Zero

Very high

Moderate

OR and AND gates can have only inputs…….

All of these
Exclusive-OR (XOR) logic gates can be constructed from ………..logic gates.

OR gates only

AND gates and NOT gates

AND gates, OR gates, and NOT gates

OR gates and NOT gates

In an unregulated power supply, if input A.C. voltage increases, the output voltage …….

Increases
Decreases
 Remains the same

None of the above

In a transistor

Ic = Ie + Ib

Ib = Ic + Ie

Ie = Ic – Ib

Ie = Ic + Ib

Why zener diodes are provided in dc supply?

For forward conduction

For reverse currents

For reference voltage

For increasing amplitude

Ripple factor of full wave rectifier

0.48

48

.048

480

If the output of the transistor amplifier 5V rms and the input is 100mV rms, the voltage gain is

50

50

100

An ammeter’s ideal resistance should be

Zero
 Unity

Infinite

The same with the circuits resistance

A heavily doped semiconductor has

High resistance

No effect on the semiconductor characteristics

More heat dissipation

Zero resistance

Low resistance

Output waveform of the circuit given below is

a
 b

A power supply which has voltage regulation of ……….. is unregulated power supply

0%

5%

10 %

8%
A transistor converts

Dc power into ac power

Ac power into dc power

High resistance into low resistance

Low resistance into high resistance

The capacitors are considered in the dc equivalent circuit of a transistor amplifier.

Short

Partially short

Open
Partially open

The bias condition for a transistor to be used as a linear amplifier is called

forward-reverse

reverse-reverse

forward-forward

collector bias

An LED

emits light when reverse biased

senses light when reverse biased

doest emit any light

emits light when forward biased

acts as a variable resistance

Which of the items below is not true for a transistor?

It is the current gain of a common-base configuration

It is the ratio of the change in collector current to the change in emitter current

It is usually having a value of unity in some approximations

It is having a value Ic=zaro

 It is the ratio of the change in collector current to the change in base current.

Refer to the figure given below if a load resistance of 600Ω is placed at the output the
maximum gain would be

65.5

6.55

0.655

655

Program and shift (e.g MSc Physics Evening) *

BS Physics Morning

BS Physics Evening

MSc Physics Morning

MSc Physics Evening

If the load current drawn by unregulated power supply increases, the d.c. output voltage ………

Increases

Decreases
Stays the same

None of the above

Circuits which produce an output wave shape resembling that of a symmetrical or

asymmetrical square wave are called

Timing generator

Frequency generator
 Multivibrator

Single vibrator

Which of the following can be source of supply in dc power supplies?

Battery

Dry cell

Full wave rectifier

cell

All of these

A Multi meter is used to measure___________

Only AC current

Only DC voltage

Both AC and DC quantities

Resistance only

Capacitance

Student Name *

m zubair arshad

What diode has no depletion layer?

Varactor

Varistor

Schottky diode

Zener

Shockley diode

To increase current capacity, cells are connected in

parallel

series

series- parallel

parallel- series
 vertically

Which of the applications filters used for?

a. Reducing ripples
b. Increasing ripples
c. Increasing phase change
d. Increasing amplitude
e. Low ripple

Ripple factor of a half wave rectifier is_________Im is the peak current and RL is load
resistance)

1.21

0.48

1.414

1.4

When a transistor is fully saturated,

The emitter current is at its minimum value

The transistor alpha is at its maximum value

The current is zero at emitter

The beta of the transistor is at minimal value

The collector current is at its maximum value

In an unregulated power supply, if input A.C. voltage increases, the output voltage …….

Increases

Decreases

Remains the same

None of these

The Zener current will be minimum when …………

Load current is maximum

Load current is minimum

 Load current is zero

None of the above

Ina common emitter amplifier, the capacitor from emitter to ground is called the

Coupling capacitor

Bypass capacitor
Decoupling capacitor

Tuning capacitor

Refer to the figure given below the value of gain is

a. 170
b. 171
c. 100
d. 17

In a BJT, if the collector-base junction and the base-emitter junction are both reverse-biased,
which region is the BJT operating in?

Starting region

Saturation region

Active region
 Cutoff region

None of the mentioned

A power supply can deliver a maximum rated current of 0.5 A at full-load output voltage of 20
V. What is the minimum load resistance that you can connect across the supply?

10 Ω

20 Ω

15 Ω

40 Ω

The number of depletion region in transistor is_____ *

a. 1
b. 2
c. 3
d. 4

The collector of the transistor is____ doped? *

a. Heavily
b. Moderately

c. Lightly
d. None of these

To deflect electrons to desired positions on the screen of a television tube, we

use? *
a. Circuit breaker
b. Electric current
c. Electromagnets
 d. Fuse

The emitter of the diode is____ doped? *

a. Heavily

b. Moderately
c. Lightly
None of these

The output of an AND gate with three inputs, A, B, and C, is HIGH when ____. *
a. A = 1, B = 1, C = 0
b. A = 0, B = 0, C = 0
c. A = 1, B = 1, C = 1

d. A = 1, B = 0, C = 1

If a signal passing through a gate is inhibited by sending a LOW into one of the
inputs, and the output is HIGH, the gate is___ *
a. AND
b. NAND

c. NOR
d. OR

Which of the following logical operations is represented by the + sign in Boolean

algebra? *
a. inversion
 b. AND
c. OR

d. complementation

Output will be a LOW for any case when one or more inputs are zero for an: *
a. OR gate
b. NOT gate
c. AND gate

d. NOR gate

The output of a NOR gate is HIGH if ____. *

a. all inputs are HIGH
b. any input is HIGH
c. any input is LOW
d. all inputs are LOW

The format used to present the logic output for the various combinations of
logic inputs to a gate is called an *
a. Boolean constant
b. Boolean variable
c. truth table

d. input logic function

The Boolean expression for a 3-input AND gate is ____. *

 a. X = AB
b. X = ABC

c. X = A + B + C
d. X = AB + C

If the input to a NOT gate is A and the output is X, then ____. *

a. X = A
b. X= A~

c. X = 0
d. none of the above

Which of the following gates has the exact inverse output of the OR gate for all
possible input combinations? *
a. NOR

b. NOT
c. NAND
d. AND

2-input NOR gate is equivalent to a ____. *

a. negative-OR gate
b. negative-AND gate
c. negative-NAND gate

d. none of the above

Zener diodes are also known as
a. Voltage regulators
b. Breakdown diode

c. Forward bias diode

d. None of these

Which of the following can be used in series with a Zener diode so that
combination has almost zero temperature coefficient? *
a. Diode

b. Resistor
c. Transistor
d. MOSFET

. Zener diodes can be effectively used in voltage regulator. However, they are
these days being replaced by more efficient *
a. Operational Amplifier
b. MOSFET
c. Integrated Circuits

d. None of the mentioned

Which of the following is true about the temperature coefficient or TC of the

Zener diode? *
a. For Zener voltage less than 5V, TC is negative
b. For Zener voltage around 5V, TC can be made zero
c. For higher values of Zener voltage, TC is positive
 d. All of the these

Which of the following is true about the resistance of a Zener diode? *

a. It has an incremental resistance
b. It has dynamic resistance
c. The value of the resistance is the inverse of the slope of the i-v
characteristics of the Zener diode
d. All of these

Amount of current drawn from output of an amplifier or other circuits through

load resistance is called. *
a. Clock
b. Load

c. Drain
d. Input

Gain of common emitter amplifier is to determine by ratio of AC output voltage

to.
a. Collector voltage
b. Emitter voltage
c. Base voltage
d. Drain voltage

In common emitter amplifier, amplified output with respect to input is. *

a. In phase
b. 90˚ out of phase
 c. 180˚ out of phase

d. 360˚ out of phase

Measure of how well an amplifier maintains its design value over changes in
temperature or other factor is called. *
a. measurement
b. maintenance
c. stability

d. loading

If AC emitter current of common amplifier is 3.80 m A then AC emitter resistance

will be. *
a. 5.3Ω
b. 2.45 Ω
c. 6.58 Ω

d. 8.32 Ω

If supply frequency of a transformer increases, the secondary output voltage of

the transformer *
a. Increase

b. Decrease
c. Remain the same
d. Any of the above
A transformer transform *
a. Current
b. power
c. all of these
d. Voltage

Transformer core are laminated in order to. *

a. Reduce hysteresis loss
b. Reduce hysteresis & eddy current loss
c. Maximize eddy current loss

d. none of these

The rating of transformer may be expressed in ____. *

a. KW
b. KVA
c. KVB
d. none of these

A Step Up transformer _____. *

a. Step Up the level of Voltage
b. Step down the level of current
c. Step up level the power
d. Both a and b
A zener diode has ……….. *
a. An amplifier
b. A voltage regulator

c. A rectifier
d. A multivibrator
The doping level in a zener diode is …………… that of a crystal diode
a. The same as
b. Less than
c. More than
d. None of the above

A zener diode is always ………… connected. *

a. Reverse

b. Forward
c. Either reverse or forward
d. None of the above

In the break down region zener diode behave like a ___ source. *
a. Constant voltage

b. Constant current
c. Constant resistance
d. None of the above

A zener diode is destroyed if it………….. *

 a. Is forward biased
b. Is reverse biased
c. Carrier more than rated current

d. None of the above

When current is only forward biased *

a. The only current is the hole current
b. The only current is electron current
c. The only current is majority charge carriers
d. The current is produced by both holes and electrons

When forward biased is a diode then *

a. Blocks current
b. Conduction current

c. Has a high resistance

d. Drops a large resistance

Battery is connected between Negative Terminal to N-region and Positive

Terminal to P-region is called. *
a. Forward biased

b. Reverse biased
c. Both a & b
d. None
The width of depletion region is increases in *
a. Forward bias
b. Reverse bias

c. Both A & B
d. None

If the battery voltage is above a particular limit (Reverse bias breakdown voltage)
this breakdown is called. *
a. Electrical break down
b. Vacuum breakdown
c. Avalanche Breakdown

d. None

If only one half cycle of input AC wave is converted into DC wave is called…… *
a. Half wave rectification

b. Full wave rectication

c. Both of these
d. None of these

Which circuit has been represented in the associated circuit diagram? *

a. Captionless Image
b. Half wave rectifier
c. Full wave rectifier
d. NOT gate
e. AND gate
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