IES - Electronics Engineering - Analog Electronic Circuits

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IES E & T Topic wise Questions Analog Electronic Circuits

YEAR 1999 MCQ 1

Assertion(A): A monostable multivibrator can be used to alter the pulse width a repetitive pulse train. Reason (R): Monostable multivibrator has a single stable state. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 2

Assertion (A): Miller sweep circuit producing sawtooth waveform is a relaxation oscillator. Reason (R): The active device alternately supplies power to the load and relaxes when it is cut off. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true

IES E & T Topic wise 1999-2009 Analog Electronic Circuits

www.gatehelp.com MCQ 3

Assertion (A): In the circuit shown in the figure, above a prescribed value of load current IL , V0 will gradually fall. Reason (R): A above the prescribed value, as load current IL increases, IB decreases.

(A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 4

Assertion (A): A large negative feedback is deliberately introduced in an amplifier to make its gain independent of the variation of parameters of the active device and other circuit components. Reason (R): A large negative feedback results in a high value of return difference compared to unity, which makes the feedback gain inversely proportional to the feedback factor. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 5

The given figure shows a composite transistor consisting of a MOSFET Page 2

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IES E & T Topicwise 1999-2009 Analog Electronic Circuits

and a bipolar transistor in cascode

The MOSFET has a trans-conductance gm of 2 mA/V and the bipolar transistor has β _Δh fe i of 99. The overall transconductance of the composite transistor is (A) 198 mA/V

(B) 19.8 mA/V

(C) 1.98 A/V

(D) 1.98 mA/V

MCQ 6

In a single-stage differential amplifier, the output offset voltage is basically dependent on the mismatch of (A) VBE , IB and β

(B) VBE and IB

(C) IB and β

(D) VBE and β

MCQ 7

The input resistance of a common emitter stage can be increased by 1.

unbypassing emitter resistance

2.

bootstrapping

3.

biasing it at low quiescent current

4.

using compounded BJTs

The correct sequence in descending order of the effectiveness of these methods is (A) 2, 4, 1, 3 (B) 4, 3, 2, 1 (C) 2, 4, 3, 1

(D) 4, 2, 3, 1 Page 3



The collector voltage VC of the circuit shown in the given figure is approximately

(A) 2 V

(B) 4.6 V

(C) 8 V

(D) 8.6 V

MCQ 9

Thermal runaway will take place if the quiescent point is such that (B) VCE < VCC (A) VCE > 1 VCC 2 (C) VCE < 2VCC (D) VCE < 1 VCC 2 MCQ 10

Circuit shown in the given figure represents

(A) an astable multivibrator (B) a monostable multivibrator (C) voltage controlled oscillator (D) ramp generator Page 4

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MCQ 11

In a feedback series regulation circuit, the output voltage is regulated by controlling the (A) magnitude of the input voltage (B) gain of the feedback transistor (C) reference voltage (D) voltage drop across the series pass transistor MCQ 12

A three-terminal monolithic IC regulator can be used as (A) an adjustable output voltage regulator alone (B) an adjustable output voltage regulator and a current regulator (C) a current regulator and a power switch (D) a current regulator alone MCQ 13

Which one of the following devices is NOT used as the controller in a stabilizer? (A) Diac

(B) Triac

(C) SCR

(D) Power transistor

MCQ 14

A second-order band-pass active filter can be obtained by cascading a low-pass second-order section having cut-off frequency fOH with a high-pass second-order section having cut-off frequency fOL , provided (A) fOH > fOL (C) fOH = fOL

(B) fOH < fOL (D) fOH # 1 fOL 2

MCQ 15

If a class C power amplifier has an input signal with frequency of 200 kHz and the width of collector current pulses of 0.1 μs , then the duty cycle of the amplifier will be (A) 1%

(B) 2%

(C) 10%

(D) 20% Page 5



The given circuit has a feedback factor of

(A) − RC /RS

(B) − RE /RC

(C) − RE /RS

(D) − RC /RE

MCQ 17

A Hartley oscillator is used for generating (A) very low frequency oscillation (B) radio-frequency oscillation (C) microwave oscillation (D) audio-frequency oscillation MCQ 18

The output voltage V0 of the given circuit

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(A) − 100 V

(B) − 100 mV

(C) 10 V

(D) − 10 mV

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MCQ 19

The voltage gain versus frequency curve of an Op-Amp is shown in the given figure

The gain-bandwidth product of the Op-Amp is (A) 200 Hz

(B) 200 MHz

(C) 200 kHz

(D) 2 MHz

MCQ 20

The v 0 of the Op-Amp circuit shown in the given figure is

(A) 11 v1

(B) 10 v1

(C) v1

(D) zero

MCQ 21

A 12 V monolithic regulator is adjusted to obtain a higher output voltage as shown in the given figure Page 7


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The v 0 will be (A) 12 V

(B) 17 V

(C) 24 V

(D) 29 V

MCQ 22

The voltage V0 of the circuit shown in the given figure is

(A) 5 V

(B) 3.1 V

(C) 2.5 V

(D) zero

YEAR 2000 MCQ 23

Assertion (A): Op-amps with FET input stages have less gain than those with BJT. Reason (R): BJT has higher transconductance than FET. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true Page 8

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MCQ 24

Assertion (A): For equal outputs, the harmonic distortion is reduced in CE amplifier with the introduction negative feedback. Reason (R): Nonlinear distortion usually arises due to signals traversing the large part of the dynamic characteristic of the transistor at the output stage. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true and R is false (D) A is false but R is true MCQ 25

Assertion (A): Thyristors are preferred over power diodes in variable power rectifiers. Reason (R): Thyristors provide controlled rectification even though they have more power loss in comparison to power diodes. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 26

A common emitter amplifier circuit is shown in the given figure

The slope of AC load line is (A) −b 1 + 1 l RL RC

(B) −b

1 RL + RC l

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(C) − 1 RL

(D) − 1 RC

MCQ 27

An amplifier circuit is shown in the given figure:

The voltage gain (V0 /Vs) is (A) 4/3.33

(B) 100

(C) 150

(D) 160

MCQ 28

Consider the following statements: A totem pole configuration used is the output state of an op-amp has the advantage of using 1.

only n-p-n BJTs

2.

complementary symmetrical pair of transistors.

3.

only one transistor

Which of these statement is/are correct? (A) 1 alone (B) 2 alone (C) 3 alone

(D) 1 and 3

MCQ 29

A 1 ms pulse can be stretched to 1 s pulse by using (A) an astable multivibrator (B) a monostable multivibrator (C) a bistable multivibrator (D) a Schmitt trigger circuit Page 10

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MCQ 30

An FET is a better chopper than a BJT because it has (A) lower offset voltage (B) higher series ON resistance (C) lower input current (D) higher input impedance MCQ 31

Consider the following statements regarding the bootstrap biasing arrangement for a BJT emitter follower: 1.

The input impedance is very high.

2.

The voltage gain is exactly equal to one.

3.

The output impedance is equal to zero.

Which of these statements is correct? (A) None (B) 2 alone (C) 3 alone

(D) 1 alone

MCQ 32

In the circuit shown in the given figure, the approximate voltages at the transistor

(A) base and emitter respectively are − 8 V and − 7.3 V (B) base and collector respectively are − 8 V and − 5 V (C) collector and emitter respectively are − 8 V and − 7.3 V (D) base, emitter and collector respectively are − 8 V , − 7.3 V and −5 V Page 11



Consider the following statements: The lower cut-off frequencies for an RC coupled CE amplifier depend on 1. input and output coupling capacitors 2.

emitter bypass capacitor

3.

junction capacitors

Which of these statements is/are correct? (A) 1 alone (B) 2 alone (C) 1 and 2

(D) 2 and 3

MCQ 34

The op-amp circuit shown in the given figure is

(A) a high-pass circuit

(B) a low-pass circuit

(C) a band pass circuit

(D) an all-pass circuit

MCQ 35

Consider the following statements: Sziklai pair 1. is also called complementary Darlington. 2.

acts like a single p-n-p transistor with a very high current gain.

3.

can be used in class B push-pull power amplifier.

Which of these statements are correct? (A) 1 and 2 (B) 1 and 3 (C) 2 and 3

(D) 1, 2 and 3

MCQ 36

Which one of the following power amplifiers has the maximum Page 12

www.gatehelp.com efficiency? (A) Class A

(B) Class B

(C) Class AB

(D) Class C


MCQ 37

If a common emitter amplifier with an emitter resistance Re has an overall transconductance gain of − 1 mA/V , a voltage gain of − 4 and desensitivity of 50, then the value of the emitter resistance Re would be (A) 50 kΩ (B) 0.98 kΩ (C) 50 kΩ

(D) 0.98 kΩ

MCQ 38

The voltage gain of an amplifier without feedback respectively are 100 and 20. The percentage of negative feedback (β) would be (A) 4% (B) 5% (C) 20%

(D) 80%

MCQ 39

If the Q of a single-stage single-turned amplifier is doubled, then its bandwidth will (A) remain same (B) become half (C) become double

(D) become four times

MCQ 40

An amplifier using BJT has two identical stages each having a lower cut-off (3 dB) frequency of 64 Hz due to coupling capacitor. The emitter bypass capacitor also provides a lower cut-off (3 dB) frequency due to emitter degeneration alone of 64 Hz. The lower of (3 dB) frequency of the overall amplifier is nearly (A) 100 Hz (B) 128 Hz (C) 156 Hz

(D) 244 Hz

MCQ 41

Consider the following statements in relation to a large value of capacitor filter used in a full-wave rectifier: Page 13


www.gatehelp.com It gives the 1. low conduction period for the diode rectifier. 2.

increased peak current rating of the diode.

3.

large peak inverse voltage rating of the diode.

Which of these statements are correct? (A) 1, 2 and 3 (B) 2 and 3 (C) 1 and 2

(D) 1 and 3

MCQ 42

In every practical oscillator, the loop gain is slightly larger than unity and the amplitude of the oscillations is limited by the (A) magnitude of the loop gain (B) onset of non-linearity (C) magnitude of the gain of the amplifier (D) feedback transmission factor MCQ 43

In the circuit shown in the given figure, the current flowing through resistance of 100 Ω would be

(A) 8 mA

(B) 10 mA

(C) 20 mA

(D) 100 mA

MCQ 44

Which one of the following sets of circuits can be obtained by using a 555 timer? Page 14

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(A) Pulse modulator and amplitude demodulator (B) Pulse modulator and astable multivibrator (C) Amplitude demodulator and AC to DC converter (D) AC to DC converter and astable multivibrator MCQ 45

The input voltage of Zener regulator varies from 20 V to 30 V. The load current varies from 10 mA to 15 mA. If the Zener voltage is 5 V , the value of series resistor will be (A) 1 kΩ

(B) 1.5 kΩ

(C) 1.66 kΩ

(D) 2.5 kΩ

MCQ 46

CE configuration is the most preferred transistor configuration when used as a switch because it (A) requires only one power supply (B) requires low voltage or current (C) is easily understood by every one (D) has small ICEO MCQ 47

The thermal run-away in a CE transistor amplifier can be prevented by biasing the transistor in such a manner that (A) VCE > VCC 2

(B) VCE < VCC 2

(C) VCE = VCC 2

(D) VCE = 0

YEAR 2001

MCQ 48

In the circuit shown in the given figure, V0 is given by Page 15


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(A) sin (t − π/4)

(B) sin (t + π/4)

(C) sin t

(D) cos t

MCQ 49

Assertion (A): In an op-amp circuit when one input terminal of the op-amp is grounded, the other terminal becomes a virtual ground. Reason (R): Input impedance of the op-amp is high. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is false MCQ 50

Assertion (A): While using UJT for the generation of saw-tooth voltage, it has to be biased so that it can work within the range of V-I characteristic. Reason (R): Within a range of its V-I characteristic, the UJT has negative resistance and can be used as an oscillator. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 51

Assertion (A): In an amplifier with negative feedback, the gainstability is improved by the factor 1 + Aβ where A is the magnitude Page 16

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of gain and β is the feedback factor. Reason (R): The relation between gain with feedback A f and gain without feedback A, is A f =

1 dA A . Thus dA f = Af 1 + Aβ A 1 + Aβ

(A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true

MCQ 52

Assertion (A): Two stage stagger-tuned amplifier should have greater bandwidth and flatter pass band. Reason (R): When synchronous tuning is used in two cascaded tuned circuits, the bandwidth reduces considerably. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true

MCQ 53

Match List-I (Circuit name) with List-II (Circuit diagram) and select the correct answer using the codes given below the lists:

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Codes: (A) (B) (C) (D)

a 1 2 1 2

b 2 1 2 1

c 3 3 4 4

d 4 4 3 3

MCQ 54

Thermal runaway is not possible in FET because as the temperature of FET increase (A) the mobility decrease (B) the transonductance increase (C) the drain current increase (D) the mobility increases MCQ 55

In a 741 op-amp, there is 20 dB/decade fall-off starting at a relatively low frequency. This is due to the

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(A) applied load

(B) internal compensation

(C) impedance of the source

(D) power dissipation in the chip

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MCQ 56

The input differential stage of op-amp 741 is biased at about 10 μA current. Such a low current of the input stage gives (A) high CMRR (B) high differential gain (C) low differential gain

(D) high input impedance

Which of these are corrent? (A) 1 and 2

(B) 1, 2 and 4

(C) 3 and 4

(D) 1, 2, 3 and 4

MCQ 57

The condition to be satisfied to prevent thermal runaway in a transistor amplifier where (PC = Power dissipated at Collector, Tj = Junction temperature , TA = Ambient temperature , Q = Thermal resistance ) is (A) δPc > 1 δTj Q

(B) δPc < 1 δTA Q

(C) δPc < 1 δTj Q

(D) δPc > 1 δTA Q

MCQ 58

Consider the following statements: The function of bleeder resistance in filter circuit is to 1. maintain minimum current necessary for optimum inductor filter operation. 2.

work as voltage divided in order to provide variable output from the supply.

3.

provide discharge to capacitors so that output becomes zero when the circuit has been de-energised.


(D) 1, 2 and 3

MCQ 59

Consider the following rectifier circuits: 1. Half-wave rectifier without filter. 2.

Full-wave rectifier without filter. Page 19


www.gatehelp.com 3.

Full-wave rectifier with series inductance filter.

4.

Full-wave rectifier with capacitance filter

The sequence of these rectifier circuits in decreasing order of their ripple factor is (A) 1, 2, 3, 4 (B) 3, 4, 1, 2 (C) 1, 4, 3, 2

(D) 3, 2, 1, 4

MCQ 60

The use of a rectifier filter in a capacitor circuit gives satisfactory performance only when the load (A) current is high

(B) current is low

(C) voltage is high

(D) voltage is low

MCQ 61

In a single-stage RC coupled common emitter amplifier, the phase shift at the lower 3 dB frequency is (A) zero

(B) 135c

(C) 180c

(D) 225c

MCQ 62

The main drawback in the performance of shunt peaked wide band amplifier is (A) too low gain at low frequency (B) reduced gain at middle frequency (C) poor phase response (D) that the maximum gain of the stage is small MCQ 63

A relaxation oscillator is one which (A) has two stable states (B) oscillates continuously (C) relaxes indefinitely (D) produces non-sinusoidal output Page 20

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YEAR 2002 MCQ 64

Assertion (A): Operational amplifiers should have a high slew rate for good transient response. Reason (R): Slew rate is the maximum rate of change of the output voltage of the operational amplifier when a large amplitude step is applied to its input. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 65

Assertion (A): An operational amplifier should have a low input offset current. Reason (R): Input impedance of op-amp should be very high. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 66

Assertion (A): An operational amplifier can amplify very low frequency including d.c. signals. Reason (R): op-amp uses very large coupling capacitor for cascading the various stages. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true Page 21



Assertion (A): To obtain high switching speed in BJT based logic circuits, transistors are operated in active region. Reason (R): In active region transistor works as a linear element. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 68

In a circuit, if the open loop gain is 106 and output voltage is 10 volt , the differential voltage should be (A) 10 μV (B) 0.1 V (C) 100 μV

(D) 1 μV

MCQ 69

An operational amplifier possesses (A) very large input resistance and very large output resistance (B) very small input resistance and very small output resistance (C) very large input resistance and very small output resistance (D) very small input resistance and very large output MCQ 70

A BJT is to be used in a high frequency circuit in common emitter amplifier. For a higher upper cur-off frequency (C μ, C π and r0 have their usual meanings) (A) C μ should be as small as possible (B) r0 and C μ should be as large as possible (C) C π and C μ should be as large as possible (D) r0 , C π and C μ should be as large as possible MCQ 71

Consider the following statements regarding a common emitter amplifier. It can be converted into an oscillator by: Page 22

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providing adequate positive feedback

2.

phase shifting the output by 180c and feeding this phase-shifted output to the input

3.

using only a series tuned circuit as a load on the amplifier

4.

using a negative resistance device as a load on the amplifier


Which of the above statements are correct? (A) 1, 2, 3 and 4 (B) 1 and 2 (C) 1, 3 and 4

(D) 3 and 4

MCQ 72

Consider the following statements: In order to generate square wave from a sinusoidal input signal one can use 1.

Schmitt trigger circuit.

2.

Clippers and amplifier.

3.

Monostable multivibrators.

Which of the above statements/is are correct? (A) 1 alone (B) 1 and 2 (C) 2 and 3

(D) 1, 2 and 3

MCQ 73

An op-amp circuit is shown in the figure given below. Different inputs and output are given under List-I and List-II. Match List-I (Inputs) with List-II (Outputs) and select the correct answer using the codes given below the lists:

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Codes:

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a

b

c

d

(A)

2

4

1

3

(B)

1

3

2

4

(C)

2

3

1

4

(D)

1

4

2

3

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MCQ 74

The PIV rating of the diodes used in power supply circuits are chosen by which one of the following criteria? (Vm is the peak input supply voltage to the rectifier circuit used in the power supply) (A) The diodes that are to be used in a full wave rectifier should be rated 2Vm and in bridge rectifier equal to Vm (B) The diodes that are to be used in a full wave rectifier should rectifier equal to 2Vm (C) All diodes should be rated for Vm only (D) All diodes should be rated for 2Vm MCQ 75

An RC amplifier stage has a bandwidth of 500 kHz. What will be the rise time of this amplifier stage? (A) 0.35 μs

(B) 0.7 μs

(C) 1.0 μs

(D) 2.0 μs

MCQ 76

In the circuit shown above, If R1 >> R p and the impulses can completely saturated transistor Q1 , then the output voltage V0 will be

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MCQ 77

The power input to an amplifier is 2 μW . The power gain of the amplifier is 40 dB. The output power of the amplifier is (A) 80 μW

(B) 200 μW

(C) 20 mW

(D) 80 mW

MCQ 78

Given below are 2 sets of diagram one set shows 4 circuits with inputs; the order shows the output (V0). Match List-I (inputs) with List-II (Outputs) and select the correct answer using the codes given below the lists:

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Codes: (A) (B) (C)

a 1 2 1

b 3 3 4

c 2 1 2

d 4 4 3 Page 27


www.gatehelp.com (D)

2

4

1

3

MCQ 79

A class B push pull type amplifier with transformer coupled load uses two transistors rated 10 W each. What is the maximum power output one can obtain at the load from this circuit? (A) 40 W

(B) 50 W

(C) 60 W

(D) 70 W

MCQ 80

In the circuit shown,

the transistor is biased at (A) 0 mA

(B) 5 mA

(C) 3.9 mA

(D) 3

MCQ 81

An op-amp circuit is shown in the figure.

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The output V0 will be (assume ideal op-amp) (A) equal to zero because the input is zero (B) dependent on element values hence nothing can be predicted without a knowledge of element values (C) a square wave varying between + VCC and − VCC (D) a sinusoidal wave of amplifier VCC MCQ 82

An amplifier will generate stable sinusoidal oscillations if we provide feedback such that (A) its pole lie close to jω-axis in the right half of s-plane (B) its poles lie close to jω-axis in the left half of s-plane (C) its poles lie on the + ve real axis in s-plane (D) its poles lie anywhere in s-plane MCQ 83

A non-inverting op-amp is shown below (assume ideal o-amp)

The output voltage V0 for an input Vi = [2 + sin (100t)] V (A) 3/2 sin (100t) (B) 3 sin (100t) (C) 2 sin (100t)

(D) 3 sin (100t) + 1/2

YEAR 2003 MCQ 84

Match List-I (Circuit) with List-II (Property) and select the correct answer using the codes given below the lists: List-I Page 29


www.gatehelp.com a.

R-C coupled single-stage amplifier

b.

Emitter follower

c.

Common base amplifier

d.

Darlington amplifier

List-II 1.

Beta multiplier

2.

Constant current source

3.

Very high input impedance

4.

Phase inverter with voltage gain

Codes: a 3 4 3 4

(A) (B) (C) (D)

b 4 3 4 3

c 1 1 2 2

d 2 2 1 1

MCQ 85

Consider the following statements in respect of a transistor R-C coupled amplifier: 1.

The low frequency response is determined by the transistor junction capacitors.

2.

The high frequency response is limited by coupling capacitors.

3.

The Miller capacitance reduces the gain at high frequencies.

4.

As the gain is increases the bandwidth gets reduced.


(D) 1 and 4

MCQ 86

Match List-I (Circuit Name) with List-II (Characteristics) and select the correct answer using the codes given below the lists: List-I

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a.

Schmitt trigger

b.

Monostable multivibrator

c.

Astable multivibrator

www.gatehelp.com d.


Blocking oscillator

List-II 1.

It needs a pulse transformer

2.

It is used to generator gating pulse whose width can be controlled

3.

It is a bistable circuit

4.

It has no stable state

Codes: (A) (B) (C) (D)

a 3 2 3 2

b 2 3 2 3

c 4 1 1 4

d 1 4 4 1

MCQ 87

The biasing shown in the below circuit is

(A) Emitter bias

(B) Self bias

(C) Potential divider bias

(D) Bootstrap bias

MCQ 88

Which of the following main properties of a bipolar junction transistor make it necessary for the transistor to have bias stabilization? 1. Variation of VBE with temperature 2.

Variation of hFE with temperature

3.

Variation of ICO with temperature

4.

Variation of hFE with transistor replacement Page 31


www.gatehelp.com 5.

Variation of VBE with transistors replacement

6.

Variation of ICO with transistor replacement

Select the correct answer using the codes given below; (A) 1, 2 and 6 (B) 1, 3 and 4 (C) 2, 3 and 5

(D) 3, 4, 5 and 6

MCQ 89

A triangular square wave generator uses (A) A sine wave oscillation and a comparator (B) An integrator and a comparator (C) A differentiator and a comparator (D) A sine wave oscillator and a clipper MCQ 90

An amplifier has two identical cascaded stages. Each stage has a bandwidth of 20 kHz. The overall bandwidth shall approximately be equal to (A) 10 kHz (B) 12.9 kHz (C) 20 kHz

(D) 28.3 kHz

MCQ 91

The common emitter current gain-bandwidth product of a transistor (fT ) is defined as the frequency at which (A) Alpha of the transistor falls by 3 dB (B) Beta of the transistor falls by 3 dB (C) Beta of the transistor falls to unity (D) Power gain of the transistor falls to unity MCQ 92

Which of the following components control the low frequency of the R-C coupled amplifier? 1. Wiring capacitance

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2.

Parasitic capacitances of transistor

3.

Coupling capacitances

4.

Emitter bypass capacitance

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Select the correct answer using the codes given below: (A) 1 and 2

(B) 2 and 3

(C) 3 and 4

(D) 1, 2 and 4

MCQ 93

For a full-wave rectifier with shunt capacitor filter, the peak to peak ripple voltage is (A) 2IDC /fC

(B) IDC /fC

(C) IDC /2fC

(D) IDC /4fC

(where f = fundamental power line frequency, IDC = DC current ) MCQ 94

In a BJT amplifier with the introduction of feedback, the input impedance is reduced, output impedance is increased, bandwidth is increased and distortion is reduced. The feedback is (A) Voltage series

(B) Current series

(C) Voltage shunt

(D) Current shunt

MCQ 95

The stage marked X in the shown below architecture of a two-stage op-amp is

(A) Direct coupled amplifier

(B) Buffer amplifier

(C) Level shifter

(D) Blocking oscillator

MCQ 96

The current through the resistor R in the below circuit is Page 33


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(A) 1 mA

(B) 4 mA

(C) 8 mA

(D) 10 mA

MCQ 97

In the op-amp circuit shown above (assuming ideal op-amp)

(A) V0 =− 5 V

(B) V0 =+ 5 V

(C) V0 = 0

(D) V0 =− 2 V

MCQ 98

The function of the diode D in the timer circuit shown above is to Page 34

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(A) Increase the charging time of C (B) Decreases the charging time of C (C) Increase the discharging time of C (D) Decrease the discharging time of C MCQ 99

Assertion (A): If the emitter bypass capacitor of an R-C coupled, CE amplifier gets disconnected, its voltage gain increases. Reason (R): The unbypassed emitter resistor gives negative feedback. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 100

Assertion (A): A self-biased BJT circuit is more stable as compared to a fixed biased one. Reason (R): A self-biased BJT circuit uses more components as compared to a fixed biased one. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true Page 35



Assertion (A): Wien bridge oscillator is generally used as a variable audio frequency oscillator Reason (R): By varying either the capacitor or resistor value in one of the arms of the bridge, the frequency of the Wien bridge oscillator can be varied. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true

YEAR 2004 MCQ 102

Consider the following circuits:

Which one of the following statements is correct? (A) Circuit 1 is parallel connection and Circuit 2 is Darlington connection (B) Circuit 1 is cascode connection and Circuit 2 is Darlington connection (C) Circuit 1 is Darlington connection and Circuit 2 is cascode connection (D) Circuit 1 is cascode connection and Circuit 2 is parallel connection MCQ 103

An amplifier has a d.c. power supply of 15 V and draws a current of 10 mA. It produces an output of 5 V peak across a load resistance Page 36

www.gatehelp.com


of 600 Ω for a single frequency of 1 kHz. What will be its a.c. power output? (A) 260 mW

(B) 20.8 mW

(C) 520 mW

(D) 40.6 mW

MCQ 104

The transfer function of a transistor amplifier is given by Av = V0 = Vs

4240 f f c1 + j 4 105 mc1 + j 4 106 m # # Which one of the following gives the approximate upper 3 dB frequency fH* . of the amplifier? (B) 2.2 # 106 Hz (A) 4 # 105 Hz (C) 4 # 106 Hz

(D) 4.4 # 106 Hz

MCQ 105

Which one of the following is a wide-band amplifier? (A) RF amplifier

(B) IF amplifier

(C) Video amplifier

(D) AF amplifier

MCQ 106

Consider the following statements: In JFET amplifier, high frequency response can be improved by using peaking circuits containing inductors 1.

in series with drain resistance RD

2.

in series with the coupling capacitance

3.

as a feedback element between drain and gate

Which of the statements given above are correct? (A) 1 and 2 (B) 2 and 3 (C) 1 and 3

(D) 1, 2 and 3

MCQ 107

Which one of the following statements is correct? If in a double tuned voltage amplifier, the mutually coupled secondary and primary are synchronously tuned with equal Q-values then for Page 37


www.gatehelp.com the over-coupled case the maximum voltage amplification (A) is greater than that for critical coupling and the amplifier characteristic is double peaked (B) is less than that for critical coupling and the amplifier characteristics has a single peak (C) is same as that for critical coupling and the amplifier characteristic is double peaked (D) is less than that for critical coupling and the amplifier characteristic is doubled peaked MCQ 108

A tuned amplifier has a voltage gain of 100 and a bandwidth of 10 kHz. It is required to increase the bandwidth of 20 kHz. This can be achieved by which one of the following ways? (A) By doubling the gain (B) By doubling the resonant frequency (C) By halving the Q of the coil (D) By halving the power supply voltage MCQ 109

A d.c. to d.c. converter has an efficiency of 80% and is supplying a load of 24 W at 240 V. What is the current drawn from the battery if the converter is working from a batter of 12 V? (A) 0.1 A

(B) 2.0 A

(C) 2.5 A

(D) 10 A

MCQ 110

Consider the following circuit:

Page 38


www.gatehelp.com What is the function of diode D2 in the above circuit? (A) To avoid saturation of the Op-Amp (B) To provide negative feedback when the input is negative (C) To reduce reverse breakdown voltage of D1 (D) As a buffer MCQ 111


Which one of the following expressions for V0 is correct? (A) V0 = Vz b R1 + R2 l (B) V0 = AVz R + R1 + R 2 (C) V0 = AVz b1 + R1 l R2

(D) V0 = AVz b

R1 + R 2 R + R1 + R 2 l

MCQ 112

Which one of the following statements is not correct in respect of a series transistor feedback voltage regulator? (A) The regulation factor can be improved by increasing the h fe of the shunt transistor (B) The regulation factor can be improved by increasing the resistance between the collector of the shunt transistor and the collector of the series transistor (C) Output resistance can be reduced by using a Darlington pair in place of the series transistor (D) Output resistance can be reduced by reducing the h fe of the shunt transistor Page 39



Consider the following Op-Amp circuit:

What is the output voltage V0 in the above Op-Amp circuit? (A) + 10 V

(B) − 10 V

(C) + 11 V

(D) − 11 V

MCQ 114


What is the value of R 4 in the above circuit, if the voltage V− and V+ are to be amplified by the same amplification factor? (A) 7 kΩ

(B) 22 kΩ

(C) 33 kΩ

(D) 35 kΩ

MCQ 115

What is the load current IL in the circuit below? Page 40

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(A) − 5 mA

(B) − 10 mA

(C) + 25 mA

(D) + 50 mA


MCQ 116

A 50 Hz symmetric square wave is applied to the RC circuit shown in the diagram given below:

Which one the following is the correct shape of the output waveform?

Page 41


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MCQ 117


For the circuit shown above, which one of the following is a correct statement? (A) D2 does not conduct for any value of Vi (B) v 0 = 10 V for all values of vi > 10 V (C) v 0 = 0 V for all values of vi < 0 V (D) v 0 = 10 V for all values of vi > 0 V MCQ 118

Assertion (A): In a transistor switching circuit, it is desirable that the transistor should not be driven into hard saturation for fast switching applications. Reason (R): When a transistor is under saturation on state, both its emitter-base and collector-base junctions remain under forward bias. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true Page 42

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MCQ 119


What is the circuit shown above? (A) Miller sweep

(B) Bootstrap sweep

(C) Schmitt trigger

(D) Triangular wave generator

MCQ 120

Match List-I (Application of the Circuit) with List-II (Circuit Name) and select the correct answer using the codes given below the lists: List-I a.

Divider

b.

Clips input voltage at two predetermined levels

c.

Square wave generator

d.

Narrow current pulse generator

List-II 1.

Astable multivibrator

2.

Schmitt trigger

3.

Bistable multivibrator

4.

Blocking oscillator

Codes: a

b

c

d

(A)

4

2

1

3

(B)

3

2

1

4

(C)

4

1

2

3

(D)

3

1

2

4 Page 43




How does the above circuit work (A) As a logarithmic amplifier (B) As a negative clipper (C) As a positive clipper (D) As a half-wave rectifier MCQ 122


What is the type of circuit given above? (A) Monostable

(B) Ramp generator

(C) VCO

(D) Bistable multivibrator

MCQ 123

Consider the following circuit: Page 44

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What is voltage difference between collector and emitter (VCE ) in the above circuit? (B) 0 V (A) 10/3 V (C) 5 V

(D) 3 V

MCQ 124

Consider the NPN transistor circuit shown below:

What if the output voltage V0 in the above circuit? (A) 0 V (B) 12 V (C) 9 V

(D) 5 V

YEAR 2005 MCQ 125

Consider the following statements: A clamper circuit 1. adds or subtracts a dc voltage to or from a waveform. 2.

does not change the shape of the waveform. Page 45


www.gatehelp.com 3.

amplifies the waveform.

Which of the statements given above are correct? (A) 1 and 2

(B) 2 and 3

(C) 1 and 3

(D) 1, 2 and 3

MCQ 126

The noise figure of a lossy network at room temperature equals the (A) Gain of the network (B) Attenuation factor of the network (C) Equivalent noise temperature of the network (D) Input noise power MCQ 127

Assertion (A): In a Darlington connection, two transistors are connected in casecade in common emitter configuration. Reason (R): The Darlington connection aims at making the current gain very high, almost equal to the product of beta of individual transistors. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 128

Assertion (A): It is possible to use the technique of additive amplification to get a wide band amplifier. Reason (R): In additive amplifier, the overall gain of the amplifier is the sum of the gain of the individual amplifiers. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true Page 46

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MCQ 129

Assertion (A): The self bias technique as used for a JFET cannot be used for establishing an operating point for the enhancement MOSFET. Reason (R): The voltage drop across Rs is such that it reverse biased the gate (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correction explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 130

A transistor RC coupled amplifier is designed for a voltage and band gain of 20. But a measurement at a particular frequency shows the gain to be only 14. What is the likely phase shift at this frequency? (A) 180c

(B) 135c

(C) 90c

(D) 45c

MCQ 131

What is the value of Rs required to self bias an N channel JFET with Vp =− 10 V , IDSS = 40 mA and VGSQ =− 5 V ? (A) 250 Ω

(B) 500 Ω

(C) 750 Ω

(D) 1500 Ω

MCQ 132

When a voltage divider biased amplifier has its Q-point near to the middle of the dc-load line, what is the maximum unclipped peak-topeak output voltage? (A) VCEQ

(B) ICQ rL

(C) 2ICQ rL

(D) 2VCEQ

MCQ 133

fT is the frequency at which the short circuit (A) Common collector current gain has a magnitude of unity Page 47


www.gatehelp.com (B) Common base current gain has a magnitude of unity (C) Common emitter current gain has a magnitude of unity (D) Common emitter current gain has a magnitude of 1/ 2 MCQ 134

Match List-I (Type of Amplifier) with List-II (Property) and select the correct answer using the code given below the lists: List-I a.

Single ended class A

b.

Class AB push-pull

c.

Class B push-pull

d.

Class C

List-II 1.

Medium efficiency with minimum distortion

2.

High efficiency with crossover distortion

3.

Harmonic generator with highest possible conversion efficiency

4.

Poor conversion efficiency with minimum distortion

Codes: a

b

c

d

(A)

2

3

4

1

(B)

4

1

2

3

(C)

2

1

4

3

(D)

4

3

2

1

MCQ 135

A cascaded amplifier comprises N identical non-interacting stages, each having a lower 3 dB frequency of fL . If fL* is the lower 3 dB frequency of the cascaded amplifier, then which one of the following is correct?

Page 48

(A) fL* = fL

(B) fL* = fL

21/N − 1

(C) fL* = fL / 21/N − 1

(D) fL* = fL /N

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MCQ 136

Consider the following statements: 1.

To achieve wide bandwidth, a transistor with a small Cb, c is chosen.

2.

To achieve wide bandwidth, transistor with a small Cb, e is chosen.

3.

To achieve wide bandwidth, transistor with a small base spreading resistance is chosen.

Which of the statements given above are correct? (A) 1 and 2

(B) 2 and 3

(C) 1 and 3

(D) 1, 2 and 3

MCQ 137

Three amplifiers each of gain (A 0 /2) and producing a phase of 60c are connected in tandem. The feedback loop is closed through a positive gain of 0.008. What should be the value of A 0 for the system to be oscillatory? (A) + 10

(B) − 10

(C) + 250

(D) + 83.3

MCQ 138

Match List-I (Name of the Oscillator) with List-II (Characteristics) and select the correct answer using the code given below the lists: List-I a.

Colpitts Oscillator

b.

Phase Shift Oscillator

c.

Tunnel diode Oscillator

d.

Relaxation Oscillator

List-II 1.

RC Oscillator

2.

LC Oscillator

3.

Negative resistance Oscillator

4.

Sweep circuits

Codes: a

b

c

d Page 49


www.gatehelp.com (A)

1

2

3

4

(B)

2

1

3

4

(C)

1

2

4

3

(D)

2

1

4

3

MCQ 139

In a half-wave rectifier, if an a.c. supply is 60 Hz, then what is the a.c. ripple at output? (A) 30 Hz

(B) 60 Hz

(C) 120 Hz

(D) 15 Hz

MCQ 140

Select the correct output (v 0) wave-shape for a given input (v1) in the clamping network given below:

Page 50

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MCQ 141

Pulses of definite width can be obtained from irregular shaped pulses: (A) When it is given as input to a monostable multivibrator (B) When it is given as triggering signal to a bistable multivibrator (C) When it is used as input to a Schmitt trigger (D) When it is used as input to a pulse transformer MCQ 142

For the circuit given below, what is IL equal to?

(A) V/RL V (C) R + RL

(B) V/R V (D) 2R + RL

MCQ 143

For a given op-amp, CMRR = 105 and differential gain = 105 . What is the common mode gain of the op-amp? (A) 1010

(B) 2 # 105

(C) 105

(D) 1

MCQ 144

A half-wave rectifier having a resistance load of 1 kΩ rectifiers an a.c. voltage of 325 V peak value and the diode has a forward resistance of 100 Ω. What is the RMS value of the current? (A) 295.4 mA

(B) 94.0 mA

(C) 147.7 mA

(D) 208.0 mA Page 51



Silicon and Germanium are not suitable for fabrication of laser diode because: (A) Their absorption coefficients are very high (B) Their emission coefficients are very low (C) They have direct band gap (D) They have indirect band gap

YEAR 2006

MCQ 146

In the circuit shown above, what is the value of transfer function I 0 /Ii ?

(A) − Z2 Z1

(B) − Z1 Z2

(C) 1 + b Z2 l Z1

(D) 1 + b Z1 l Z2

MCQ 147

Consider the following statements related to a shunt generator: 1.

The full load voltage is lower than to load voltage.

2.

The above lowering is partly due to voltage drop in armature resistance.

3.

The field current does not change with load and has no effect on generated voltage.

Which of the statements give above are correct?

Page 52

(A) 1, 2 and 3

(B) Only 1 and 2

(C) Only 2 and 3

(D) Only 1 and 3

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MCQ 148

What is the phase shift between the input and output voltage in a common base small signal amplifier (assuming ideal coupling and bypass capacitors)? (A) 180c

(B) − 180c

(C) 0c

(D) None of the above

MCQ 149

The transistor circuit shown in the figure given below is to function as an amplifier. If ICQ = 3 mA , what is the value of VCC (approximate)?

(A) 15 V

(B) − 15 V

(C) − 10 V

(D) − 13.5 V

MCQ 150

(A) 3000 Ω

(B) 1000/3 Ω

(C) 300 Ω

(D) 100 Ω

MCQ 151

Consider the following parameters of a hybrid-π equivalent circuit of Page 53


www.gatehelp.com BJT: 1.

Transconductance (gm)

2.

h fe

3.

hie

Which of the above parameters vary with temperature is similar manner (all of them decrease or all of them increase)? Select the correct answer using the code given below: (A) only 1 and 2

(B) only 2 and 3

(C) only 1 and 3

(D) 1, 2 and 3

MCQ 152

What is the main advantage of a JFET-cascade amplifier? (A) High voltage gain

(B) Low output impedance

(C) Very low input capacitance

(D) High input impedance

MCQ 153

When used for amplification, the output port side of BJT behaves as controlled current source. According to the above, the variation of which one of the following does not change the output current of an ideal BJT? (The BJT is being used in a common emitter amplifier circuit) (A) Load resistance (B) Collector to base bias voltage (C) Both load resistance and collector to base bias voltage (D) Base-emitter bias voltage MCQ 154

Where does the operating point of a class B power amplifier lie? (A) At the middle of a.c. a load line (B) Approximately at collector cut-off on both the d.c. and a.c. load lines (C) Inside the collector cut-off region on a.c. load line (D) At the middle point of d.c. load line Page 54

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MCQ 155

Consider the following statements in respect of a CC amplifier: 1. It performs a resistance transformation from low to high resistance. 2.

Its current gain is close to unity.

3.

Its voltage gain is close to unity.

4.

Its frequency range is higher than that of a CE-stage.

Which of the statements given above are correct? (A) 1, 2 and 4 (B) 1 and 3 (C) Only 2 and 4

(D) 3 and 4

MCQ 156

A CE amplifier has RL = 10 kΩ . Given hie = 1 kΩ , h fe = 50 , hre = 0 and 1/hce = 40 kΩ . What is the voltage gain? (A) − 500 (B) − 400 (C) − 50

(D) − 40

MCQ 157

In an FET common source high frequency amplifier, which one of the following is the correct expression of input capacitance Ci ? (B) Ci = Cgs + (1 − 1/Av) Cgd (A) Ci = Cgs + (1 − Av) Cgd (C) Ci = Cgd + (1 − Av) Cgs

(D) Ci = Cgd + (1 − 1/Av) Cgs

MCQ 158

The drain gate capacitance of a junction FET is 2 pF. Assuming a common source voltage gain of 20, what is the input capacitance due to Miller effect? (A) 21 pF (B) 40 pF (C) 42 pF

(D) 10 pF

MCQ 159

Assertion (A): All practical R-C phase shift oscillators generate sinusoidal oscillation with some amount of amplitude distortion, which cannot be avoided. Reason (R): The amplitude distortion of a sinusoidal oscillator is Page 55


www.gatehelp.com controlled by the onset of non-linearity of the amplifying device. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 160

Narrow pulses with adjustable mark to space ratio can be obtained from square wave input signal by using which of the following? 1.

Schmitt trigger

2.

Monostable multivibrator

3.

Clippers

Select the correct answer using the code given below: (A) Only 1 (B) Only 2 (C) 1 and 2

(D) 2 and 3

MCQ 161

A differential amplifier has inputs, V1 = 1050 μV and V2 = 950 μV with CMRR = 1000. What is the error in the differential output? (A) 10%

(B) 1%

(C) 0.1%

(D) 0.01%

MCQ 162

Consider the following statements: 1.

Stray capacitance at the input terminal of an op-amp effective introduces an additional phase lag network in feedback loop.

2.

Stray capacitance depends upon the value of resistor used in feedback.

3.

Low value of resistance has higher effects on stray capacitance

Which of the statements given above are correct?

Page 56

(A) 1, 2 and 3

(B) 2, 3 and 4

(C) 1, 3 and 4

(D) 1, 2 and 4

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MCQ 163

In the given circuit, D1 is an ideal germanium diode and D2 is a silicon diode having its cut-in voltage as 0.7 V, forward resistance as 20 Ω and reverse saturation current (Is) as 10 nA. What are the values of I and V for this circuit, respectively?

(A) 60 mA and 0 V

(B) 50 mA and 0 V

(C) 53 mA and 0.7 V

(D) 44 mA and 1.58 V

MCQ 164

The two stages of a cascade amplifier have individual upper cutoff frequencies f1 = 5 MHz and f2 = 3.33 MHz . What is the best approximation for the upper cut-off frequency of the cascade combination? (A) 4.16 MHz

(B) 3.33 MHz

(C) 2.5 MHz

(D) 5.00 MHz

MCQ 165

An amplifier has an open loop gain of 1000 ! 10 . Negative feedback is provided such that the gain variation remains within 0.1% What is the amount of feedback βF ? (A) 1/10

(B) 1/9

(C) 9/100

(D) 9/1000

MCQ 166

Consider the following statements: We would be able to achieve broad banding in a common source FET amplifier, by 1.

resonance between the shunt capacitance and a compensating inductance. Page 57


www.gatehelp.com 2.

RC compensating network between source and drain.

3.

connecting compensating network in series with the coupling capacitors.

Which of the statements given above is/are correct? (A) Only 1

(B) 1 and 2

(C) 1 and 3

(D) 2 and 3

YEAR 2007

MCQ 167

Which one of the following gain equations is correct for a MOSFET common source amplifier? (gm is mutual conductance, and RD is load resistance at the drain) (A) AV = gm /RD

(B) AV = gm RD

(C) AV = gm / (1 + RD)

(D) AV = RD /gm

MCQ 168

Which one of the following statements is correct? The rise time of an amplifier is (A) directly proportional to the upper 3 dB frequency (B) inversely proportional to the upper 3 dB frequency (C) directly proportional to the lower 3 dB frequency (D) inversely proportional to the lower 3 dB frequency MCQ 169

The 3 dB cut off frequency of a d.c. amplifier is 5 MHz. What is its rise time? (A) 350 ns

(B) 200 ns

(C) 70 ns

(D) 35 ns

MCQ 170

For the amplifier shown in the figure given below, the lower cut-off frequency depends on which of the following? Page 58

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(A) CS , CE , internal junction capacitances of transistor (B) Strong wiring capacitance (CW ), CC (C) CS , CE , CC (D) CS , CE only MCQ 171

In a class-B push-pull operation, the d.c. power drawn in 28 W. What is the power delivered by the amplifier at the ideal maximum efficiency of power conversion? (A) 28 W (B) 14 W (C) 22 W

(D) 7 W

MCQ 172

Cascode amplifier when compared with a simple common-emitter amplifier provide which of the following? (A) Higher voltage gain and same bandwidth (B) Same voltage gain but higher bandwidth (C) No change in either voltage gain or bandwidth (D) Voltage gain less than one but bandwidth equal to fT MCQ 173

Which of the following features are offered by a bipolar junction transistor amplifier in Darlington connection? 1. High voltage gain 2.

High input impedance Page 59


www.gatehelp.com 3.

High current gain

Select the correct answer using the code given below: Codes: (A) 1 and 2 only

(B) 2 and 3 only

(C) 1 and 3 only

(D) 1, 2 and 3

MCQ 174

Operating point shift can occur in an amplifier due to which one of the following? (A) Input frequency variation (B) Noise at the input (C) Parasitic capacitances (D) Power supply fluctuation MCQ 175

For a CE amplifier, d.c. load line is which one of the following plots? (A) IC versus VCE for a given value of (RC + RE ) and VCC (B) IB versus VEE for a given value of (RC + RE ) and VCC (C) IB versus VCE for a given value of IB (D) IC versus VCB for a given value of IE MCQ 176

Consider the following statements: The basic purpose of bias stabilization in a transistor circuit is to 1.

increase the voltage and current gain of the ampilifier.

2.

make the operating point of the transistor independent of temperature variation of the transistor.

3.

make the operating point independent of the replacement of the same type, Ge or Si.

Which of the statements given above are correct?

Page 60

(A) 1 and 2 only

(B) 2 and 3 only

(C) 1 and 3 only

(D) 1, 2 and 3

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MCQ 177

Match List-I (Electronic Circuit) with List-II (Characteristic) and select the correct answer using the code given below the lists: List-I a.

CE

b.

CB

c.

CC

d.

Darlington Pair

List-II 1.

The circuit introduces a phase inversion of 180c

2.

The circuit is rarely used

3.

The name, emitter follower is also used for the circuit

4.

The circuit consists of two circuits connected in cascade

Codes: a

b

c

d

(A)

1

2

3

4

(B)

2

1

3

4

(C)

2

1

4

3

(D)

1

2

4

3

MCQ 178

In an amplifier, the power output is 2 W at 5 kHz, and 0.5 W at 50 Hz. If the input power is constant at 10 mW, what is the variation (approximate) of power gain in dB at two frequencies? (log 10 2 . 0.30) (A) 6 dB

(B) 8 dB

(C) 3 dB

(D) 16 dB

MCQ 179

A power supply has a full-load voltage of 24 V. What is its no-load voltage for 5% regulation (rounded to the nearest integer)? (A) 12 V

(B) 23 V

(C) 25 V

(D) 6 V Page 61



In a negative feedback amplifier, when is the input impedance increased? (A) If the signal sampled is a voltage (B) If the signal sampled is a current (C) If the feedback signal is a voltage (D) if the feedback signal is a current

MCQ 181

A tuned amplifier has peak output at 2 MHz and quality factor 50. The bandwidth and 3 dB frequencies shall be at what values respectively? (A) 40 kHz, 2.02 MHz, 1.98 MHz (B) 40 kHz, 2.04 MHz, 1.96 MHz (C) 80 kHz, 2.04 MHz, 1.96 MHz (D) 80 kHz, 2.08 MHz, 1.92 MHz

MCQ 182

The pinch-off voltage Vp =+ 6 V for a P-channel JFET. If VGS =+ 2 V ,what is the value of VDS at which it will enter into saturation region? (A) − 6 V

(B) − 4 V

(C) + 8 V

(D) + 4 V

MCQ 183

What is the output voltage V0 of the below circuit? Page 62

www.gatehelp.com

(A) − 11 V

(B) 6 V

(C) 11 V

(D) − 6 V


MCQ 184

What is the output voltage V0 of the below circuit?

(A) − 1.1 V

(B) + 1.1 V

(C) 1.0 V

(D) 10 V

MCQ 185

Assertion (A): Many power devices utilize the case itself as one of the principal current carrying terminals. Reason (R): Such a connection maximizes the thermal resistance between the working semiconductors and the transistor case. (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A Page 63


www.gatehelp.com (C) A is true but R is false (D) A is false but R is true MCQ 186

Assertion (A): The three electrodes, Source, Drain and Gate of a FET correspond to Emitter, Base and Collector of a junction transistor respectively. Input signal is generally applied to the gate and gate voltage VG controls the electric field in the channel. Reason (R): In the input circuit, the gate and the channel act like two plates of a capacitor. A charge of one polarity on the gate induces and equal and opposite charge in the channel. As a result the conductivity of the channel can be increased or decreased by VG . (A) Both A and R are true and R is the correct explanation of A (B) Both A and R are true but R is NOT the correct explanation of A (C) A is true but R is false (D) A is false but R is true

YEAR 2008 MCQ 187

Consider the following statements: Bias stabilization in a BJT circuit is very important, because it 1.

provides high voltage and current gain.

2.

ensures large bandwidth of the amplifier.

3.

keeps the operating point unchanged with change of temperature.

Which of the above statement(s) is/are correct? (A) 1 and 2

(B) 2 and 3

(C) 3 only

(D) 1 and 3

MCQ 188

Consider the following statements: Dominant-pole frequency compensation in an OP-AMP 1. Page 64

increases the slow-rate of the OP-AMP

www.gatehelp.com 2.

increases the stability of the OP-AMP

3.

reduces the bandwidth of the OP-AMP

4.

reduces the CMRR of the OP-AMP


Which of the statements given above are correct? (A) 1 and 3 only (B) 1, 2 and 4 (C) 1 and 2 only

(D) 2 and 3 only

MCQ 189

In a practical oscillator circuit, which one of the following limits the amplitude of the oscillations? (A) Onset of non-linearity (B) Power supply voltage (C) Oscillation frequencies (D) Temperature of the active device MCQ 190

Consider the following statements: Tuned amplifier 1. are wide band amplifiers 2.

are used in radio transmitters and receivers

3.

performance is determined by Q of the circuit

Which of the statements given above are correct? (A) 1 and 2 only (B) 2 and 3 only (C) 1 and 3 only

(D) 1, 2 and 3

MCQ 191

A feed back amplifier has an open loop gain of − 100 . If 4% of the output is fed back in a degenerative loop, what is the closed loop gain of the amplifier? (A) − 33.3 (B) − 25 (C) − 20

(D) + 25

MCQ 192

Match List-I (Type of Feedback) with List-II (Effect on R in and R out Page 65


www.gatehelp.com ) and select the correct answer using the code given below the lists List-I a Voltage series b.

Voltage Shunt

c.

Current Series

d.

Current shunt

List-II 1.

R in increases and R out decreases

2.

R in and R out decrease

3.

R in and R out increase

4.

R in decreases and R out increases

Codes: a

b

c

d

(A)

1

4

3

2

(B)

3

2

1

4

(C)

3

4

1

2

(D)

1

2

3

4

MCQ 193

An amplifier has gain A = 100 180c , upper cut off frequency of 100 kHz and lower cut off frequency of 1 kHz. A negative feedback of β = 0.1 is added. Which one of the following is not correct? (A) Gain becomes 100/11 (B) Lower cut off frequency becomes (100/11) Hz (C) Upper cut off frequency becomes 1.1 MHz (D) dB of feedback is 20 log 10 11 MCQ 194

What is the collector circuit efficiency of a class B push-pull amplifier if Vm = peak load voltage ,and

Page 66

Vcc = collector supply voltage (A) η = π Vm # 100% 4 Vcc

(B) η = π Vm # 100% 2 Vcc

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(C) η = π Vcc # 100% 2 Vm


(D) η = π Vcc − Vm # 100% 4 Vm

MCQ 195

Which of the following components are chosen to construct a d.c. power supply to supply 6 V d.c. voltage from 230 V a.c. to operate a tape recorder? 1.

Step down transformer

2.

Diodes

3.

Resistors and capacitors

4.

Three-pin voltage stabilizer

Select the correct answer using the code given below: (A) 1, 2 and 3 only

(B) 1 and 4 only

(C) 3 and 4 only

(D) 1, 2, 3 and 4

MCQ 196

The figure shown is a circuit of which one of the following?

(A) Bridge rectifier

(B) Voltage doubler

(C) Rectifier with filter

(D) Comparator

MCQ 197

Which of the following components control the high frequency response of the R-C coupled amplifier? 1.

Parasitic capacitances of the transistor

2.

Coupling capacitance

3.

Stray capacitance Page 67


www.gatehelp.com 4.

Wiring capacitance

Select the correct answer using the code given below: (A) 1 and 2 only

(B) 2 and 3 only

(C) 3 and 4 only

(D) 1, 3 and 4

MCQ 198

The figure given below shows the circuit of which one of the following?

(A) Bi-stable multi-vibrator (B) Schmitt trigger (C) Monostable multi-vibrator (D) Astable multi-vibrator MCQ 199

The figure given above shows the transfer characteristics of which one of the following

Page 68

(A) Peak clipper

(B) Bottom clipper

(C) Clamper

(D) Two level clipper

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MCQ 200

Match List-I (Name of the circuit) with List-II (Property of the circuit) and select the correct answer using the code given below the lists: List-I a. Pre-amplifier b.

Power amplifier

c.

Rectifier circuit

d.

Purely resistive circuit

List-II 1.

Non-linear circuit

2.

Lumped, linear, passive, bilaterial, finite circuit

3.

Large signal amplifer

4.

Small signal amplifier

Codes: a

b

c

d

(A)

4

2

1

3

(B)

1

3

4

2

(C)

4

3

1

2

(D)

1

2

4

3

MCQ 201

Assertion (A): A high value of resistor is connected across the diode in a clamper circuit for better performance. Reason (R): If this resistor is not present, the circuit will respond to sudden decrease in the magnitude of the input pulse train, but the response to sudden increase in the amplitude will cause improper response. (A) Both A and R are individually true and R is the correct explanation of A (B) Both A and R are individually true but R is not the correct explanation of A (C) A is true but R is false (D) A is false but R is true Page 69



Assertion (A): Complementary transistors are used for class B pushpull power amplifier. Reason (R): We don’t need transformers if we use complementary transistors in class B push-pull power amplifiers. (A) Both A and R are individually true and R is the correct explanation of A (B) Both A and R are individually true but R is not the correct explanation of A (C) A is true but R is false (D) A is false but R is true MCQ 203

In a class A amplifier, VCE (max) = 15 V and VCE (min) = 1 V . The conversion efficiency for a series fed load will be equal to (A) 25% (B) 23.33% (C) 12.5%

(D) 11.67%

MCQ 204

Neutralizing capacitors are normally used in (A) Audio amplifier (B) Video amplofiers (C) RF and IF amplifiers

(D) Operational amplifiers

MCQ 205

Silicon diodes are less suited for low voltage rectifier operation because (A) it cannot withstand high temperatures (B) its reverse saturation current is low (C) its cut-in voltage is high (D) its breakdown voltage is high MCQ 206

CE configuration is the most preferred transistor configuration when used as a switch because (A) it requires only one power supply (B) it requires low voltage or current for operating the switch Page 70

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(C) it is easily understood by every one (D) it has small ICEO

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Page 71

IES - Electronics Engineering - Analog Electronic Circuits

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