POWER Electronics(700-MCQ)

Q-Which of the following devices does not belong to the transistor family?
a) IGBT
b) MOSFET
c) GTO
d) BJT

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Answer: c
Explanation: GTO is gate turn off transistor, it belongs to the Thyristor family. All the other devices belong to the transistor family.

 

Q-In a power transistor, ____ is the controlled parameter.
a) VBE
b) VCE
c) IB
d) IC

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Answer: d
Explanation: The collector current is the controlled parameter.

 

Q-For a power transistor, which of the following relations is true?
a) Ie>Ic>Ib
b) Ib>Ic>Ie
c) Ic>Ie>Ib
d) Ie=Ib

…………………..

Answer: a
Explanation: Practically speaking Ie = Ib+Ic. Ie is the highest as it is the sum of the collector and base currents. The base current is the smallest.

 

Q-Which of the following relations is true for a BJT?
a) Ic ≈ Ie
b) Ib ≈ Ic
c) Ie ≈ Ib
d) Ib ≈ Ie ≈ Ic

…………..

Answer: a
Explanation: The collector & emitter current differ only by the base current, which is very very small

 

Q-Choose the correct statement
a) A transistor will remain on as long the the base current is applied
b) A transistor remains on after a high to low pulse is applied at the base
c) A transistor will remain on as long the the collector current is applied
d) A transistor remains on after a high to low pulse is applied at the collector

…………….

Answer: a
Explanation: Unlike the thyristor devices, all the transistor family devices remain in the conducting state as long as the firing pulses are applied. This is a very important property of the transistor devices.

 

 

Q-Let’s say that a transistor is operating at the middle of the load line, then a decrease in the current gain would
a) move the Q point up
b) move the Q point down
c) result in to & fro motion of the Q point
d) not change the Q point

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Answer: b
Explanation:The current gain would decreases the collector current, shifting the Q point below.

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