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.

When a CE transistor is cut off

A. voltage across collector reduces to zero
B. voltage across collector is maximum
C. maximum collector current flows
D. maximum voltage appears across the load resistance
Answer» C. maximum collector current flows
2.

The bandwidth of an amplifier can be reduced by

A. miller effect compensation
B. pole zero compensation
C. dominant pole compensation
D. lead compensation
Answer» D. lead compensation
3.

How many cascaded stage of CE amplifiers will result in polarity inversion of the input signal?

A. Two
B. Three
C. Four
D. None
Answer» C. Four
4.

Circuit shown in the figure is

A. astable multivibrator
B. monostable multivibrator
C. VCO
D. ramp Generator
Answer» B. monostable multivibrator
5.

In a transistor, current ICBO flow when

A. some D.C. voltage is applied in the reverse direction to the emitter junction with the collector open circuit
B. some D.C. voltage is applied in the forward direction to the collector junction with the emitter open circuit
C. some D.C. voltage is applied in the reverse direction to the collector junction with the emitter open circuited
D. some D.C. voltage is applied in the forward direction to the emitter junction with the collector open circuited
Answer» D. some D.C. voltage is applied in the forward direction to the emitter junction with the collector open circuited
6.

The D.C. alpha(a) of a transistor is approximately

A. unity
B. 10 to 50
C. 100 to 500
D. 1000 to 5000
Answer» B. 10 to 50
7.

When negative feedback is used the fractional changes in closed loop gain are desensitized by the factor (1 + Av )

A. True
B. False
Answer» B. False
8.

Which of the following is the common feature between FETs and bipolars?

A. Have low input impedance
B. Have low voltage gain
C. Are difficult to bias
D. None of them
Answer» E.
9.

In figure the diode is ideal (zero cut in voltage zero forward resistance). Then the current through diode is

A. 0
B. 4 A
C. 1 A
D. none of the above
Answer» D. none of the above
10.

The circuit shown in the figure is that of

A. non-inverting amplifier
B. Inverting amplifier
C. an oscillator
D. Schmitt trigger
Answer» E.
11.

The current through common emitter resistor of a differential amplifier is called

A. differential current
B. emitter current
C. ground current
D. tail current
Answer» E.
12.

The theoretical maximum efficiency of a half wave diode rectifier is

A. 40.6%
B. 50%
C. 81.2%
D. slightly less than 100%
Answer» B. 50%
13.

2N 2430 could be a

A. semi-conductor diode
B. dual gate MOSFET
C. BJT
D. UJT
Answer» D. UJT
14.

In a transistor push pull amplifier

A. there is no dc present in the output
B. there are no even harmonics in the output
C. both (a) and (b)
D. neither (a) nor (b)
Answer» D. neither (a) nor (b)
15.

The circuit shown I/P in the figure represents

A. Low pass filter
B. High pass filter
C. Band Pass filter
D. Band stop filter
Answer» D. Band stop filter
16.

In figure the trace on the CRO will be

A. half rectifier wave
B. clamped wave
C. no trace at all
D. either (a) or (b)
Answer» C. no trace at all
17.

The depletion type MOSFET can operate in

A. depletion mode only
B. enhancement mode only
C. depletion or enhancement mode
D. neither depletion nor enhancement mode
Answer» D. neither depletion nor enhancement mode
18.

In the op-amp circuit shown in figure the current through load resistance RL is

A. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/317-222-2.png">
B. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/317-222-3.png">
C. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/317-222-4.png">
D. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/317-222-5.png">
Answer» B. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/317-222-3.png">
19.

Whenever a JFET operates above pinch-off voltage

A. depletion regions become smaller
B. drain current increase steeply
C. drain current starts decreasing
D. drain current remains nearly constant
Answer» E.
20.

A Weinbridge oscillator is a

A. VHF oscillator
B. RF oscillator
C. microwave oscillator
D. audio frequency oscillator
Answer» E.
21.

RC network shown in the given figure can provide a maximum theoretical phase shift of

A. 90
B. 180
C. 270
D. 360
Answer» C. 270
22.

Assertion (A): In the circuit shown figure the diode is used to protect the active devices. Transistor T goes into saturation when a positive pulse is applied at base and non conductingReason (R): When the current in an inductor is suddenly stopped, a high voltage is induced across it.

A. Both A and R are correct and R is correct explanation for A
B. Both A and R are correct but R is not correct explanation for A
C. A is correct R is wrong
D. A is wrong R is correct
Answer» B. Both A and R are correct but R is not correct explanation for A
23.

For full wave rectification four diode bridge rectifier is claimed to have following advantages: Less expensive transformerSmall size transformerSuitable for higher voltage applications Which of these are correct?

A. 1 and 2 only
B. 1 and 3 only
C. 2 and 2 only
D. 1, 2, 3
Answer» E.
24.

In a full wave diode rectifier circuit each diode carries current for

A. 90 in each cycle
B. 180 in each cycle
C. 270 in each cycle
D. 360 in each cycle
Answer» C. 270 in each cycle
25.

When a JFET is cut off, it's like an __________ switch and when it is saturated, it's like a __________ switch.

A. closed, open
B. open, closed
C. open, open
D. closed, closed
Answer» C. open, open
26.

An engineer designs an amplifier to have a voltage gain of 60, but when constructed it only had a gain of 50. Which of the following will increases from this type of operation?

A. Stability
B. Bandwidth
C. Distortion
D. Input resistance
Answer» D. Input resistance
27.

The given circuit has a feedback factor of

A. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/339-615-2.png">
B. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/339-615-3.png">
C. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/339-615-4.png">
D. <img src="/_files/images/electronics-and-communication-engineering/analog-electronics/339-615-5.png">
Answer» E.
28.

Assertion (A): Linear ICs include audio amplifier, wideband amplifier, RF amplifier and IF amplifierReason (R): The error voltage in a feedback circuit is very small

A. Both A and R are correct and R is correct explanation for A
B. Both A and R are correct but R is not correct explanation for A
C. A is correct R is wrong
D. A is wrong R is correct
Answer» C. A is correct R is wrong
29.

For a transistor if adc = 0.98 and emitter current IE is 2 mA, then base current will be

A. 10 A
B. 40 A
C. 80 A
D. 200 A
Answer» B. 40 A
30.

Assertion (A): The horizontal intercept of dc load line is the same as ideal cut off pointReason (R): When a transistor is in cut off region, collector current is zero

A. Both A and R are correct and R is correct explanation for A
B. Both A and R are correct but R is not correct explanation for A
C. A is correct R is wrong
D. A is wrong R is correct
Answer» B. Both A and R are correct but R is not correct explanation for A
31.

Which circuit is called swamped amplifier?

A. CC
B. CE
C. CB
D. Both (a) and (b)
Answer» B. CE
32.

In a linear op-amp circuit

A. the product of gain and bandwidth is constant
B. input can be dc only
C. input can be ac only
D. saturation may occur
Answer» B. input can be dc only
33.

In a normally biased N-P-N transistor the main current crossing the collector junction is

A. a drift current
B. a hole current
C. a diffusion current
D. same as the base current
Answer» B. a hole current
34.

The input gate current of a FET is

A. a few amperes
B. a few milli amperes
C. a few micro amperes
D. negligible
Answer» E.
35.

The enhancement type MOSFET is called a

A. normally on MOSFET
B. normally off MOSFET
C. P-type MOSFET
D. N-type MOSFET
Answer» C. P-type MOSFET
36.

For maximum unclipped output from a CE amplifier, the Q point should be

A. at the centre of dc load line
B. at the centre of ac load line
C. at the centre of collector current
D. none of the above
Answer» C. at the centre of collector current
37.

The circuit shown in figure will act as

A. differentiator
B. adder
C. clipper
D. clamper
Answer» D. clamper
38.

If three cascaded stages of amplifier have gains 10, 20 and 30 the overall voltage will be

A. 30
B. 60
C. 600
D. 6000
Answer» E.
39.

A collector collects

A. electrons from the base in case of N-P-N transistor
B. electrons from the emitter in case P-N-P transistor
C. holes from the base in case of N-P-N transistor
D. holes from the base in case of P-N-P transistor
Answer» C. holes from the base in case of N-P-N transistor
40.

Which of the following best represents the input impedance of an actual op-amp?

A. 10 ohm
B. 1 k ohm
C. 1 M ohm
D. 100 M ohm
Answer» D. 100 M ohm
41.

The input resistance of FET in the low frequency small signal operation is

A. infinitely high
B. around 1 k&ohm;
C. around 50 &ohm;
D. very small
Answer» B. around 1 k&ohm;
42.

A logarithmic amplifier has diode in the feedback path.

A. True
B. False
Answer» B. False
43.

Which configuration has high input impedance and low output impedance?

A. CB
B. CE
C. CC
D. CB and CE
Answer» D. CB and CE
44.

Assertion (A): An ac amplifier uses coupling capacitors at input and outputReason (R): The capacitive reactance varies inversely with frequency. It is infinite for dc

A. Both A and R are correct and R is correct explanation for A
B. Both A and R are correct but R is not correct explanation for A
C. A is correct R is wrong
D. A is wrong R is correct
Answer» B. Both A and R are correct but R is not correct explanation for A
45.

Common base configuration is little used because

A. it has low input impedance
B. it has high input impedance
C. it does not heat up
D. it has very high gain
Answer» B. it has high input impedance
46.

If the plate supply voltage for a plate modulated class C amplifier is E volts, the maximum plate-cathode voltage could be almost as high as

A. E
B. E/2
C. 2E
D. 4E
Answer» E.
47.

In a JFET, the lower end is called the __________ and the upper end is called the __________ .

A. source, channel
B. channel, drain
C. source, drain
D. drain source
Answer» D. drain source
48.

The changes in ambient temperature affect the open loop gain of amplifier.

A. True
B. False
Answer» B. False
49.

A semi-conductor device that behaves like two SCRs is

A. UJT
B. MOSFET
C. JFET
D. TRIAC
Answer» E.
50.

As compared to a BJT amplifier circuit, a JFET amplifier circuit

A. has low input impedance
B. has high input impedance
C. has very low input impedance
D. may have either low or high input impedance
Answer» C. has very low input impedance