Power electronics MCQ #3

1) A diode is said to be reversed biased when the

     (a) cathode is -ve with respect to the anode

     (b) anode is +ve with respect to the cathode

     (c) cathode is +ve with respect to the anode

     (d) both cathode & anode are -ve

2) Which of the following are/is the majority charge carriers in a Schottky diode?

     (a) Electrons

     (b) Holes

     (c) Both holes & Electrons carry equal current

     (d) None of the mentioned

3) Zener diodes allow a current to flow in the reverse direction, when the

     (a) current cannot flow in the reverse direction

     (b) temperature reaches above a certain value

     (c) current always flows in the reverse direction only

     (d) voltage reaches above a certain value

4)  A power transistor is a _________ device.

     (a) 2 terminal, bipolar, voltage controlled

     (b) 2 terminal, unipolar, current controlled

     (c) 3 terminal, unipolar, voltage controlled

     (d) 3 terminal, bipolar, current controlled

5) Which of the following devices does not belong to the transistor family?

     (a) MOSFET

     (b) BJT

     (c) GTO

     (d) IGBT

ANSWER: | 1-C | 2-A | 3-D | 4-D | 5-C |

6) The forward current gain α is given by

     (a) IC/IB

     (b) IC/IE

     (c) IE/IC

     (d) IE/IB

7) High frequency operation of any device is limited by the

     (a) switching losses

     (b) forward voltage rating

     (c) heat Sink arrangements

     (d) thermal conductivity

8) Which of the following terminals does not belong to the MOSFET?

     (a) Drain

     (b) Gate

     (c) Base

     (d) Source

9) The controlling parameter in MOSFET is

     (a) Vds

     (b) Ig

     (c) Vgs

     (d) Is

10)  In the internal structure of a MOSFET, a parasitic BJT exists between the

     (a) drain & gate terminals

     (b) source & drain terminals

     (c) source & gate terminals

     (d) there is no parasitic BJT in MOSFET

ANSWER: | 6-B | 7-A | 8-C | 9-B | 10-B |

11)  The N-channel MOSFET is considered better than the P-channel MOSFET due to its

     (a) low noise levels

     (b) TTL compatibility

     (c) faster operation

     (d) lower input impedance

12) The controlling parameter in IGBT is the

     (a) IG

     (b) VGE

     (c) IC

     (d) VCE

13) The structure of the IGBT is a

     (a) P-N-P structure connected by a MOS gate

     (b) N-N-P-P structure connected by a MOS gate

     (c) P-N-P-N structure connected by a MOS gate

     (d) N-P-N-P structure connected by a MOS gate

14) The approximate equivalent circuit of an IGBT consists of

     (a) a BJT & a MOSFET

     (b) a MOSFET & a MCT

     (c) two BJTs

     (d) two MOSFETs

15) The static V-I curve of an IGBT is plotted with

     (a) Vce as the parameter

     (b) Ic as the parameter

     (c) Vge as the parameter

     (d) Ig as the parameter

ANSWER: | 11-C | 12-B | 13-C | 14-A | 15-C |

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