Explore topic-wise MCQs in Testing Subject.

This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.

1.

The technique used to quickly switch off a transistor is by

A. reverse biasing its emitter to collector junction
B. reverse biasing its base to collector junction
C. reverse biasing its base to emitter junction
D. reverse biasing any junction
Answer» D. reverse biasing any junction
Discussion
2.

The collector current will not reach the steady state value instantaneously because of

A. stray capacitances
B. resistances
C. input blocking capacitances
D. coupling capacitance
Answer» B. resistances
Discussion
3.

What is the phase shift in RC coupled CE amplifier at lower 3dB frequency?

A. 180°
B. 225°
C. 270°
D. 100°
Answer» C. 270°
Discussion
4.

Find the 3-dB frequency given that the gain of RC coupled amplifier is 150, the low frequency voltage gain is 100 and the input frequency is 50Hz.

A. 50.8 hz
B. 55.9 hz
C. 60hz
D. 100hz
Answer» C. 60hz
Discussion
5.

15Hz

A. 22.73 hz
B. 612 hz
C. 673hz
D. 317 hz
Answer» C. 673hz
Discussion
6.

Consider an RC coupled amplifier at low frequency. Internal voltage gain is -120. Find the voltage gain magnitude, when given that collector resistance = 1kΩ, load = 9kΩ, collector capacitance is 0. is 0.1μF, and input frequency is 20Hz.

A. 120
B. 12
C. 15 d) -12
Answer» D.
Discussion
7.

Given that capacitance w.r.t the input node is 2pF and output node is 4pF, find capacitance between input and output node.

A. 0.67 pf
B. 1.34pf
C. 0.44pf
D. 2.2pf
Answer» B. 1.34pf
Discussion
8.

Find net voltage gain, given hfe = 50 and hie = 1kΩ.

A. 27.68
B. -22
C. 30.55
D. -27.68
Answer» E.
Discussion
9.

When applying miller’s theorem to resistors, resistance R1 is for node 1 and R2 for node 2. If R1>R2, then for same circuit, then for capacitance for which the theorem is applied, which will be larger, C1 or C2?

A. c1
B. c2
C. both are equal
D. insufficient data
Answer» B. c2
Discussion
10.

Which of the statement is incorrect?

A. at unity gain frequency the ce short circuit current gain becomes 1
B. unity gain frequency is the same as gain
Answer» B. unity gain frequency is the same as gain
Discussion
11.

In Miller’s theorem, what is the constant K?

A. total voltage gain
B. internal voltage gain
C. internal current gain
D. internal power gain
Answer» C. internal current gain
Discussion
12.

In an RC coupled CE amplifier, when the input frequency increases, which of these are incorrect?

A. reactance csh decreases
B. voltage gain increases
C. voltage gain decreases due to shunt capacitance
D. an rc coupled amplifier behaves like a low pass filter
Answer» C. voltage gain decreases due to shunt capacitance
Discussion
13.

Gain bandwidth frequency is GBP= 3000 Mhz. The cut-off frequency is f=10Mhz. What is the CE short circuit current gain at the β cutoff frequency?

A. 212
B. 220
C. 300
D. 200
Answer» B. 220
Discussion
14.

8 x 106.

A. 200
B. 100
C. 141.42
D. 440.2
Answer» D. 440.2
Discussion
15.

Given that transition capacitance is 5 pico F and diffusion capacitance is 80 pico F, and base emitter dynamic resistance is 1500 Ω, find the β cut-off frequency.

A. 7.8 x 106 rad/s
B. 8.0 x 106 rad/s c) 49.2 x 106 rad/s d) 22.7 x 106 rad/s
Answer» B. 8.0 x 106 rad/s c) 49.2 x 106 rad/s d) 22.7 x 106 rad/s
Discussion
16.

We cannot use h-parameter model in high frequency analysis because

A. they all can be ignored for high frequencies
B. junction capacitances are not included in it
C. junction capacitances have to be included in it
D. ac analysis is difficult for high frequency using it
Answer» C. junction capacitances have to be included in it
Discussion
17.

If a C.E. stage has a load Rl and transconductance gm, what is the factor by which the capacitance between the base and the collector at the output side gets multiplied?

A. 1 + 1/gmrl
B. 1 – 1/gmrl
C. 1 + 2/gmrl
D. 1 – 2/gmrl
Answer» B. 1 – 1/gmrl
Discussion
18.

If a C.E. stage has a load Rl and transconductance gm, what is the factor by which the capacitance between the base and the collector at the input side gets multiplied?

A. 1 + gmrl
B. 1 – gmrl
C. 1 + 2*gmrl
D. 1 – 2*gmrl
Answer» B. 1 – gmrl
Discussion
19.

Which effect plays a critical role in producing changes in the frequency response of the B.J.T.?

A. thevenin’s effect
B. miller effect
C. tellegen’s effect
D. norton’s effect
Answer» B. miller effect
Discussion
20.

If the total capacitance between the base and the emitter increases by a factor of 2, the transit frequency

A. reduces by 2
B. increases by 2
C. reduces by 4
D. increases by 4
Answer» B. increases by 2
Discussion
21.

If the transconductance of the B.J.T increases, the transit frequency

A. increases
B. decreases
C. doesn’t get affected
D. doubles
Answer» B. decreases
Discussion
22.

Which parasitic capacitors don’t affect the frequency response of the C.C. stage of the B.J.T.?

A. ccs
B. ccs and cb
C. cb
D. ccs and cµ
Answer» B. ccs and cb
Discussion
23.

Which parasitic capacitors don’t affect the frequency response of the C.B. stage of the B.J.T.?

A. none of the parasitic capacitances
B. all the parasitic capacitances
C. some of the coupling capacitors
D. ccs and cb
Answer» C. some of the coupling capacitors
Discussion
24.

Which parasitic capacitors do not affect the frequency response of the C.E. stage, of the B.J.T.?

A. cje and cb
B. ccs and cµ
C. cb and cµ
D. no parasitic capacitor gets deactivated
Answer» E.
Discussion
25.

3 BJT FREQUENCY RESPONSE

A. cje and cb
B. ccs and cµ
C. cb
D. ccs and cb
Answer» C. cb
Discussion
26.

During high frequency applications of a B.J.T, which parasitic capacitors arise between the collector and the base?

A. cje and cb
B. ccs
C. cπ
D. cµ
Answer» E.
Discussion
27.

During high frequency applications of a B.J.T., which parasitic capacitors arise between the collector and the emitter?

A. no capacitor arises
B. ccs
C. cb
D. ccs and cb
Answer» B. ccs
Discussion
28.

During high frequency applications of a B.J.T., which parasitic capacitors arise between the base and the emitter?

A. cje and cb
B. ccs
C. cb
D. ccs and cb
Answer» B. ccs
Discussion
29.

Under what condition can the circuit shown be called a compensated attenuator.

A. c1r1 = c2r2
B. c1r2 = c2r1
C. c1c2 = r1r2
D. r1 = 0
Answer» B. c1r2 = c2r1
Discussion
30.

General representation of the frequency response curve is called

A. bode plot
B. miller plot
C. thevenin plot
D. bandwidth plot
Answer» B. miller plot
Discussion
31.

Which of the following is not a classification of amplifiers on the basis of their frequency response?

A. capacitively coupled amplifier
B. direct coupled amplifier
C. bandpass amplifier
D. none of the mentioned
Answer» E.
Discussion
32.

STC networks can be classified into two categories: low-pass (LP) and high-pass (HP). Then which of the following is true?

A. hp network passes dc and low frequencies and attenuate high frequency and opposite for lp network
B. lp network passes dc and low frequencies and attenuate high frequency and opposite for hp network
C. hp network passes dc and high frequencies and attenuate low frequency and opposite for lp network
D. lp network passes low frequencies only and attenuate high frequency and opposite for hp network
Answer» C. hp network passes dc and high frequencies and attenuate low frequency and opposite for lp network
Discussion
33.

Consider a voltage amplifier having a frequency response of the low-pass STC type with a dc gain of 60 dB and a 3-dB frequency of 1000 Hz. Then the gain db at

A. f = 10 hz is 55 db
B. f = 10 khz is 45 db
C. f = 100 khz is 25 db
D. f = 1mhz is 0 db
Answer» E.
Discussion
34.

The signal whose waveform is not effected by a linear circuit is

A. triangular waveform signal
B. rectangular waveform signal
C. sine/cosine wave signal
D. sawtooth waveform signal
Answer» D. sawtooth waveform signal
Discussion
35.

In a small signal differential gain vs input CM level graph, the gain decreases after V2 due to:

A. as the input voltage increases, the output will be clipped
B. when the input voltage to the transistors are high, the transistor enters saturation region and increases the current, which inturn decreases the output voltage = vdd – rd.iss
C. when common mode voltage is greater than or equal to v2, the input transistors enter triode region, the gain begins to fall
D. increasing the input voltage beyond v2 causes the gate oxide to conduct and the gain is reduced
Answer» D. increasing the input voltage beyond v2 causes the gate oxide to conduct and the gain is reduced
Discussion
36.

In Common Mode Differential Amplifier, the outputs Vout1 and Vout2 are related as:

A. vout2 is in out of phase with vout1 with same amplitude
B. vout2 and vout1 have same amplitude but the phase difference is 90 degrees
C. vout1 and vout2 have same amplitude and are in phase with each other and their respective inputs
D. vout1 and vout2 have same amplitude and are in phase with each other but out of phase with their respective inputs
Answer» E.
Discussion
37.

The inputs to the differential amplifier are applied at

A. at x and y
B. at the gates of m1 and m2
C. all of the mentioned
D. none of the mentioned
Answer» C. all of the mentioned
Discussion
38.

If source resistance in an amplifier circuit is zero, then voltage gain (output to input voltage ratio) and source voltage gain (output to source voltage ratio) are the same.

A. true
B. false
Answer» B. false
Discussion
39.

The Differential output of the difference amplifier is the amplification of

A. difference between the voltages of input signals
B. difference between the output of the each transistor
C. difference between the supply and the output of the each transistor
D. all of the mentioned
Answer» B. difference between the output of the each transistor
Discussion
40.

Consider the following circuit, where source current = 10mA, hfe = 50, hie = 1100Ω, then for the transistor circuit, find output resistance RO and input resistance RI.

A. ro = 0, ri = 21Ω
B. ro = ∞, ri = 0Ω
C. ro = ∞, ri = 21Ω
D. ro = 10, ri = 21Ω
Answer» D. ro = 10, ri = 21Ω
Discussion
41.

Given that IB = 5mA and hfe = 55, find load current.

A. 28ma
B. 280ma
C. 2.5a
D. 2a
Answer» C. 2.5a
Discussion
42.

For the given circuit, input resistance RI = 20Ω, hfe = 50. Output resistance = ∞. Find the new values of input and output resistance, if a base resistance of 2kΩ is added to the circuit.

A. ri = 20Ω, ro = ∞
B. ri = 20Ω, ro = 2kΩ
C. ri = 59Ω, ro = ∞
D. ri = 59Ω, ro = 2kΩ
Answer» D. ri = 59Ω, ro = 2kΩ
Discussion
43.

Given hfe = 60, hie=1000Ω, hoe = 20μ Ω–, hre = 2 * 10-4. Find the current gain of the BJT, correct up to two decimal points.

A. – 58.44
B. -59.21
C. – 60.10
D. – 60.00
Answer» B. -59.21
Discussion
44.

Consider the circuit. Given hfe = 50, hie = 1200Ω. Find voltage gain.

A. – 278
B. -277.9
C. – 300
D. – 280
Answer» B. -277.9
Discussion
45.

Given yfs = 3.6mS and yos = 0.02mS, determine r0?

A. 100kohm
B. 50mohm
C. 50kohm
D. 20kohm
Answer» D. 20kohm
Discussion
46.

In a small signal equivalent model of an FET, What does gm VGS stand for?

A. a pure resistor
B. voltage controlled current source
C. current controlled current source
D. voltage controlled voltage source
Answer» C. current controlled current source
Discussion
47.

A FET has IDSS=4ID and gm0 = 10mS then gm =

A. 10ms
B. 20ms
C. 5ms
D. 14ms
Answer» D. 14ms
Discussion
48.

Find the maximum value of gm for FET with IDSS=10mA, Vp=-2V, VGS=5V?

A. 10ms
B. 20ms
C. 1ms
Answer» B. 20ms
Discussion
49.

002. What is the value ofgm?

A. 1
B. 2
C. 0.002
Answer» D.
Discussion
50.

Determine the value of output impedance for JFET, if the value of gm =1mS?

A. 1kohm
B. 0
C. 100kohm
D. 5kohm
Answer» B. 0
Discussion