BJT MCQ

21. For transistor operation in active region

  1. Emitter-base diode is always forward biased and the collector-base diode is always reversed based
  2. Emitter-base diode is a ways reversed-based and the collector-base diode is always forward-based
  3. Both the emitter-base diode and the collector-base diode are forward based
  4. Both the emitter has diode and the collector-base diode are reversed-based
Answer
Answer. a

22. In a properly biased N-P-N transistor most of the electrons from the emitter

  1. Passes to the collector through the base
  2. Recombine with holes with base
  3. Recombine with holes in emitter itself
  4. Are stopped by the junction barrier
Answer
Answer. a

23. In the common-emitter transistor circuit, if the current gain is 100 and the collector current is 10mA, the base current is

  1. 10 μA
  2. 100 μA
  3. 1 A
  4. 10 A
Answer
Answer. b

24. In a BJT circuit a PNP transistor is replaced by NPN transistor. To analyse the new circuit.

  1. All calculations are done earlier have to be repeated
  2. Replace all calculated voltages by reverse values
  3. Replace all calculated currents by reverse value
  4. Replace all calculated voltages and currents by reverse values
Answer
Answer. d

25. What is the correct sequence of the following step in the fabrication of a monolithic bipolar junction transistor?

  1. Emitter diffusion
  2. Base diffusion
  3. Buried layer formation
  4. epi-layer formation

Select the correct answer using the codes given below

  1. 3, 4, 1, 2
  2. 4, 3, 1, 2
  3. 3, 4, 2, 1
  4. 4, 3, 2, 1
Answer
Answer. d

26. The input impedance of the transistor is

  1. High
  2. Low
  3. Very high
  4. Almost zero
Answer
Answer. b

27. For a transistor to act as a current amplifier.

  1. Both its emitter-base junction and collector-base junction are forward biased
  2. Both its emitter-base junction and collector-base thin junction are reverse biased
  3. Its emitter-base junction is forward biased while collector-base junction is reverse biased
  4. Its emitter-base junction is reverse biased while collector-base junction is forward biased
Answer
Answer. c

28. The β in a transistor configuration is the current gain of

  1. CB configuration
  2. CC configuration
  3. CD configuration
  4. CE configuration
Answer
Answer. d

29. Which one of the following types of noise gains importance at high frequency?

  1. Shot noise
  2. Random noise
  3. Impulse noise
  4. Transit-time noise
Answer
Answer. d

30. ‘Heat sink’ is generally attached with

  1. Base of transistor
  2. Emitter of transistor
  3. Collector of transistor
  4. None of these
Answer
Answer. c
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