Explore topic-wise MCQs in Electronic Devices Circuits.

This section includes 29 Mcqs, each offering curated multiple-choice questions to sharpen your Electronic Devices Circuits knowledge and support exam preparation. Choose a topic below to get started.

1.

In JFET, when operated above the pinch-off voltage, the

A. Depletion region becomes smaller
B. Drain current starts decreasing
C. Drain current remains practically constant
D. Drain current increases steeply
Answer» D. Drain current increases steeply
Discussion
2.

Directions: Each of the next items consists of two statements, one labeled as the `Assertion (A)' and the other as 'Reason (R)' You are to examine these two statements carefully and select the answers to these items using the codes given below :Assertion (A): The resistance of a FET in a non-conducting region is very high.Reason (R): The FET is a semiconductor device.

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
Answer» C. A is true but R is false
Discussion
3.

A class – A transformer coupled, transistor power amplifier is required to deliver a power output of 10 watts. The maximum power rating of the transistor should not be less than __________.

A. 5 W
B. 10 W
C. 20 W
D. 40 W
Answer» D. 40 W
Discussion
4.

In JFET after pinch off the drain current______.

A. Suddenly increases
B. Suddenly goes to zero
C. Slowly decreases
D. Becomes constant
Answer» E.
Discussion
5.

Miller sweep has the following dataR = 1K ohms, C = 1 PF, V = 10 VoltsIts sweep speed is?

A. 103 V/S
B. 106 V/S
C. 104 V/S
D. 1010 V/S
Answer» E.
Discussion
6.

In a common source JFET amplifier, the output voltage is

A. 180° out of phase with input
B. In phase with input
C. 90° out of phase with input
D. none of the above
Answer» B. In phase with input
Discussion
7.

In a N-channel JFET, drain current is maximum when Gate Voltage VGS is ______

A. equal to + VDD
B. more than to + VDD
C. equal to “0 volts”
D. All of these
Answer» D. All of these
Discussion
8.

Each of the following items consists of two statements, one labeled as ‘Statement (I)’ and the other as ‘Statement (II)’. Examine these two statements carefully and select the answers to these items using the code given below.Statement (I): Thermal runaway is not possible in a FET.Statement (II): As the temperature of FET increases, the mobility of carriers decreases.

A. Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
B. Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)
C. Statement (I) is true but Statement (II) is false
D. Statement (I) is false but Statement (II) is true
Answer» B. Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I)
Discussion
9.

In a JFET, operating above pinch-off voltage, the

A. drain current increases steeply
B. drain current remains practically constant
C. drain current starts decreasing
Answer» C. drain current starts decreasing
Discussion
10.

A FET is

A. very high input resistance
B. very low input resistance
C. high connection emitter junction
D. toward biased P-N junction
Answer» B. very low input resistance
Discussion
11.

Consider the following statements regarding an FET :1. its operation depends upon the flow of majority carriers only.2. It has a high input resistance.3. It is suitable for high frequency.4. Its operation depends upon the flow of both majority and minority carriers.Which of the above statements are correct ?

A. 1, 2, 3 and 4
B. 1 and 2 only
C. 2 and 3 only
D. 3 and 4 only
Answer» C. 2 and 3 only
Discussion
12.

Choose the correct statement when V­GS = 0 and VDS = 0 in a JFET

A. The depletion regions around the p-n junctions are equal in thickness and symmetrical
B. ID is maximum
C. ID is half of the maximum value
D. The depletion regions around the p-n junctions are not equal in thickness
Answer» B. ID is maximum
Discussion
13.

For n-channel field effect transistor running in enhancement mode, a conductive channel is formed only from:

A. +ve gate to source voltage
B. -ve gate to source voltage
C. +ve source to gate voltage
D. -ve source to gate voltage
Answer» B. -ve gate to source voltage
Discussion
14.

JFET is considered as a voltage-controlled device because ______

A. gate current is controlled by drain voltage
B. drain current is controlled by gate voltage
C. gate current is controlled by the source voltage
D. drain current is controlled by source voltage
Answer» C. gate current is controlled by the source voltage
Discussion
15.

For a p-channel Si JFET, Na = 3 × 1016 cm-3, Nd = 1018 cm-3. Channel thickness dimension is a = 0.33 μm. Find approximate pinch-off voltage Vp. (ni = 1010 cm-3, VT = 26 mV)

A. 2.5 V
B. 1.7 V
C. 4.2 V
D. 3.6 V
Answer» C. 4.2 V
Discussion
16.

In a drain characteristics of JFET, drain current is maximum when VGS is

A. reverse biased
B. zero
C. negative
D. positive
Answer» C. negative
Discussion
17.

For an n-channel silicon JFET with a = 2 × 10-4 cm and channel resistivity ρ = 5Ω –cm, μn = 1300 cm2/V-s and ε0 = 9 × 10-12 F/m, the pinch-off voltage, Vp, is nearly

A. 2.30 V
B. 2.85 V
C. 3.25 V
D. 3.90 V
Answer» C. 3.25 V
Discussion
18.

In a Field Effect Transistor (FET), the maximum voltage that can be applied between any two terminals is given by

A. Low |VDS| causing avalanche breakdown
B. Low |VGS| causing avalanche breakdown
C. |VDS| = 0 when gate is reverse-biased
D. |VGS| = 0 when gate is reverse-biased
Answer» B. Low |VGS| causing avalanche breakdown
Discussion
19.

TO_USE_FET_AS_A_VOLTAGE_CONTROLLED_RESISTOR,_IN_WHICH_REGION_IT_SHOULD_OPERATE??$

A. Ohmic region
B. cut off
C. Saturation
D. cut off and saturation
Answer» B. cut off
Discussion
20.

For a p-channel FET, What is the direction of current flow?$

A. Source to drain
B. Drain to source
C. Gate to source
D. Gate to drain
Answer» B. Drain to source
Discussion
21.

For an n-channel FET, What is the direction of current flow?$

A. Source to drain
B. Drain to source
C. Gate to source
D. Gate to drain
Answer» C. Gate to source
Discussion
22.

What is the value of drain current when Vgs=pinch off voltage?

A. 0A
B. 1A
C. 2A
D. Cannot be determined
Answer» B. 1A
Discussion
23.

The Shockley equation is __________________

A. I<sub>D</sub> = (1 – V<sub>gs</sub>/V<sub>p</sub>)<sup>2</sup>
B. I<sub>D</sub> = I<sub>DSS</sub> (1 – V<sub>gs</sub>/V<sub>p</sub>)<sup>2</sup>
C. I<sub>D</sub> = I<sub>DSS</sub> (1 – V<sub>gs</sub>/V<sub>p</sub>)<sup>1</sup>
D. I<sub>D</sub> = I<sub>DSS</sub> (1 + V<sub>gs</sub>/V<sub>p</sub>)<sup>2</sup>
Answer» C. I<sub>D</sub> = I<sub>DSS</sub> (1 ‚Äö√Ñ√∂‚àö√ë‚àö¬® V<sub>gs</sub>/V<sub>p</sub>)<sup>1</sup>
Discussion
24.

What is the value of current when the gate to source voltage is less than the pinch off voltage?

A. 1A
B. 5A
C. 100A
D. 0
Answer» E.
Discussion
25.

For a FET when will maximum current flows?

A. V<sub>gs</sub> = 0V
B. V<sub>gs</sub> = 0v and V<sub>ds</sub> >= |V<sub>p</sub>|
C. V<sub>DS</sub> >= |V<sub>p</sub>|
D. V<sub>p</sub> = 0
Answer» C. V<sub>DS</sub> >= |V<sub>p</sub>|
Discussion
26.

What is the main advantage of FET which makes it more useful in industrial applications?

A. Voltage controlled operation
B. Less cost
C. Small size
D. Semiconductor device
Answer» D. Semiconductor device
Discussion
27.

Comparing the size of BJT and FET, choose the correct statement?

A. BJT is larger than the FET
B. BJT is smaller than the FET
C. Both are of same size
D. Depends on application
Answer» B. BJT is smaller than the FET
Discussion
28.

Which of the following statement is true about FET?

A. It has high output impedance
B. It has high input impedance
C. It has low input impedance
D. It does not offer any resistance
Answer» C. It has low input impedance
Discussion
29.

FET is a voltage controlled device.

A. True
B. False
Answer» B. False
Discussion