1. When the drain voltage in an n-MOSFET is negative, it is operating in

  1. active region
  2. inactive region
  3. ohmic region
  4. reactive region
Answer. b

2. The regions of operation of a MOSFET to work as a linear resistor and linear amplifier are

  1. cut-off and saturation respectively
  2. triode and cut-off respectively
  3. triode and saturation respectively
  4. saturation and triode respectively
Answer. c

3. Two MOSFETs M1 and M2 are connected in parallel to carry a total current of 20A. The drain to source voltage of M1 is 2.5V and that of M2 is 3V. What are the drain currents of M1 and M2 when the current sharing series resistances are each of 0.5Ω?

  1. 10.5 A and 9.5 A
  2. 9.5 A and 10.5 A
  3. 10.5 A and 10.5 A
  4. 9.5 A and 9.5 A
Answer. a

4. The lower turn off time of MOSFET when compared to BJT can be attributed to which one of the following?

  1. input impedance
  2. positive temperature coefficient
  3. absence of minority carriers
  4. on-state resistance
Answer. c

5. What is the main difference between MOSFETs and BJTs in terms of their I-V characteristics?

  1. current is quadratic with VGS for MOSFETs and linear with VBE for BJTs
  2. current is linear with VGS for MOSFETs and exponential with VBE for BJTs
  3. current is exponential with VGS/VBE in both these devices, but rise is faster in MOSFETs
  4. current is quadratic with VGS for MOSFETs and exponential with VBE for BJTs
Answer. d

6. The modified work function of an n-channel MOSFET is -0.85 V. If the interface charge is 3 × 10-4 C/m2 and the oxide capacitance is 300 μF/m2, the flat band voltage is

  1. -1.85 V
  2. -0.15 V
  3. +0.15 V
  4. +1.85 V
Answer. d

7. Enhancement mode is connected with which one of the following?

  1. tunnel diode
  3. photodiode
  4. varactor diode
Answer. b

8. The MOSFET switch in its on-state may be considered equivalent to

  1. resistor
  2. capacitor
  3. inductor
  4. battery
Answer. b

9. Which of the following pair is not correctly matched?

  1. MOSFET – unipolar device
  2. BJT – switching power loss
  3. MOSFET – high ON state conduction power loss
  4. IGBT – voltage-controlled device
Answer. b

10. Identify the incorrect statement regarding power MOSFET.

  1. these are so constructed as to avoid punch through
  2. the channel length is relatively large and the channel width is relatively small
  3. these do not experience any minority charge carrier storage
  4. these can be put in parallel to handle large currents
Answer. b

11. An E-MOSFET with its gate connected to its drain is an example of

  1. a three-terminal device
  2. an active load
  3. a passive load
  4. a switching device
Answer. b

12. Which of the following devices revolutionised the computer industry?

  1. JFET
  4. Power FET
Answer. c

13. A D-MOSFET can operate in the

  1. depletion mode only
  2. enhancement mode only
  3. depletion mode or enhancement mode
  4. low impedance mode
Answer. c

14. For operation of depletion type MOSFET the gate voltage is kept

  1. positive
  2. highly positive
  3. zero
  4. negative
Answer. d

15. A MOSFET can be used as

  1. resistor
  2. capacitor
  3. switch
  4. all the above
Answer. d

16. Most commonly used insulating layer material for MOSFET is

  1. GeO2
  2. Al2O3
  3. As2O5
  4. SiO2
Answer. d

17. Dynamic memory cells are constructed using

  1. transistors
  2. flip-flops
  3. MOSFETs
  4. FETs
Answer. c

18. MOSFET can be used as

  1. current controlled capacitor
  2. voltage controlled capacitor
  3. current controlled inductor
  4. voltage controlled inductor
Answer. b

19. Which of the following parameters are affected due to short channel MOSFET geometry

  1. mobility of carriers
  2. threshold voltage
  3. drain current
  1. only i
  2. only ii
  3. both i and iii
  4. i, ii and iii
Answer. d

20. Which of the following characterisitics does an active loaded MOS differential circuit possess?

  1. high CMRR
  2. low CMRR
  3. high delay
  4. high differential gain
Answer. d
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