Bipolar Junction Transistor (BJT) MCQs
1. A transistor has__________
A. one pn junction
B. two pn junctions
C. three pn junctions
D. four pn junctions
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2. The number of depletion layers in a transistor is_____________
A. four
B. three
C. one
D. two
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3. The base of a transistor is_____________ doped
A. heavily
B. moderately
C. lightly
D. none of the above
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4. The element that has the biggest size in a transistor is___________
A. collector
B. base
C. emitter
D. collector-base-junction
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5. In a pnp transistor, the current carriers are_____________
A. acceptor ions
B. donor ions
C. free electrons
D. holes
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6. The collector of a transistor is___________ doped
A. heavily
B. moderately
C. lightly
D. none of the above
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7. A transistor is a____________ operated device
A. current
B. voltage
C. both voltage and current
D. none of the above
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8. In a npn transistor____________ are the minority carriers
A. free electrons
B. holes
C. donor ions
D. acceptor ions
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9. The emitter of a transistor is_____________ doped
A. lightly
B. heavily
C. moderately
D. none of the above
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10. In a transistor, the base current is about___________ of emitter current
A. 25%
B. 20%
C. 35 %
D. 5%
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11. At the base-emitter junctions of a transistor, one finds ……………
A. a reverse bias
B. a wide depletion layer
C. low resistance
D. none of the above
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12. The input impedance of a transistor is ………….
A. high
B. low
C. very high
D. almost zero
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13. Most of the majority carriers from the emitter ………………..
A. recombine in the base
B. recombine in the emitter
C. pass through the base region to the collector
D. none of the above
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14. The current IB is …………
A. electron current
B. hole current
C. donor ion current
D. acceptor ion current
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15. In a transistor ………………..
A. IC = IE + IB
B. IB = IC + IE
C. IE = IC – IB
D. IE = IC + IB
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16. The value of α of a transistor is ……….
A. more than 1
B. less than 1
C. 1
D. none of the above
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Q17. IC = αIE + ………….
A. IB
B. ICEO
C. ICBO
D. βIB
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18. The output impedance of a transistor is ……………..
A. high
B. zero
C. low
D. very low
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19. In a tansistor IC = 100 mA and IE = 100.2 mA. The value of β is__________
A. 100
B. 50
C. about 1
D. 200
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20. In a transistor if β = 100 and collector current is 10 mA, then IE is_________
A. 100 mA
B. 100.1 mA
C. 110 mA
D. none of the above
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21. Three regions of BJT are_________
A. Emitter, Collector, and Gate
B. Emitter, Base and Collector
C. Emitter, Gate, and Source
D. Source, Drain, and Collector
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22. The region which is lightly doped in BJT is_________
A. Base
B. Collector
C. Emitter
D. Any of above
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23. The region which is heavily doped___________
A. Base
B. Collector
C. Emitter
D. Any of above
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24. In a transistor IC = Ic mA and IE = Ie mA. The value of β is_________
A. 50
B. 100
C. 150
D. 200
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25. The transistor is a ____________ operated device
A. Voltage
B. Current
C. Both of these
D. None of these
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26. Which of the following is the correct bias arrangement for a BJT if it is to be operated as an amplifier_______
A. Both Base emitter junction and Base-collector junction are reverse biased
B. Both Base emitter junction and Base-collector junction are forward biased
C. Base emitter junction is reverse biased and Base-collector junction is forward biased
D. Base emitter junction is forward biased and Base-collector junction is reverse biased
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27. What is the value of collector current when the base resistor is open
A. 0 mA
B. 0.7 mA
C. 1.5 mA
D. Infinity
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