Multiple Choice Questions and Answers on Transistors

Multiple Choice Questions and Answers on Transistors

Q1. A transistor has …………………

  1. one pn junction
  2. two pn junctions
  3. three pn junctions
  4. four pn junctions

Answer : 2

Q2. The number of depletion layers in a transistor is …………

  1. four
  2. three
  3. one
  4. two

Answer : 4

Q3. The base of a transistor is ………….. doped

  1. heavily
  2. moderately
  3. lightly
  4. none of the above

Answer : 3

Q4. The element that has the biggest size in a transistor is ………………..

  1. collector
  2. base
  3. emitter
  4. collector-base-junction

Answer : 1

Q5. In a pnp transistor, the current carriers are ………….

  1. acceptor ions
  2. donor ions
  3. free electrons
  4. holes

Answer : 4

Q6. The collector of a transistor is …………. doped

  1. heavily
  2. moderately
  3. lightly
  4. none of the above

Answer : 2

Q7. A transistor is a …………… operated device

  1. current
  2. voltage
  3. both voltage and current
  4. none of the above

Answer : 1

Q8. In a npn transistor, ……………. are the minority carriers

  1. free electrons
  2. holes
  3. donor ions
  4. acceptor ions

Answer : 2

Q9. The emitter of a transistor is ………………… doped

  1. lightly
  2. heavily
  3. moderately
  4. none of the above

Answer : 2

Q10. In a transistor, the base current is about ………….. of emitter current

  1. 25%
  2. 20%
  3. 35 %
  4. 5%

Answer : 4

Q11. At the base-emitter junctions of a transistor, one finds ……………

  1. a reverse bias
  2. a wide depletion layer
  3. low resistance
  4. none of the above

Answer : 3

Q12. The input impedance of a transistor is ………….

  1. high
  2. low
  3. very high
  4. almost zero

Answer : 2

Q13. Most of the majority carriers from the emitter ………………..

  1. recombine in the base
  2. recombine in the emitter
  3. pass through the base region to the collector
  4. none of the above

Answer :3

Q14. The current IB is …………

  1. electron current
  2. hole current
  3. donor ion current
  4. acceptor ion current

Answer : 1

Q15. In a transistor ………………..

IC = IE + IB

IB = IC + IE

IE = IC – IB

IE  = IC + IB

Answer : 4

Q16. The value of α of a transistor is ……….

  • more than 1
  • less than 1
  • 1
  • none of the above

Answer : 2

Q17. ICαIE + ………….

  1. IB
  2. ICEO
  3. ICBO
  4. βIB

Answer : 3

Q18. The output impedance of a transistor is ……………..

  1. high
  2. zero
  3. low
  4. very low

Answer : 1

Q19. In a tansistor, IC = 100 mA and IE = 100.2 mA. The value of β is …………

  1. 100
  2. 50
  3. about 1
  4. 200

Answer : 4

Q20. In a transistor if β = 100 and collector current is 10 mA, then  IE is …………

  1. 100 mA
  2. 100.1 mA
  3. 110 mA
  4. none of the above

Answer : 2

Q21. The relation between β and  α is …………..

  1. β = 1 / (1 – α )
  2. β = (1 – α ) / α
  3. β = α / (1 – α )
  4. β = α / (1 + α )

Answer : 3

Q22. The value of β for a transistor is generally ………………..

  1. 1
  2. less than 1
  3. between 20 and 500
  4. above 500

Answer : 3

Q23. The most commonly used transistor arrangement is …………… arrangement

  1. common emitter
  2. common base
  3. common collector
  4. none of the above

Answer : 1

Q24. The input impedance of a transistor connected in …………….. arrangement is the highest

  1. common emitter
  2. common collector
  3. common base
  4. none of the above

Answer : 2

Q25. The output impedance of a transistor connected in ……………. arrangement is the highest

  1. common emitter
  2. common collector
  3. common base
  4. none of the above

Answer : 3

Q26. The phase difference between the input and output voltages in a common base arrangement is …………….

  1. 180o
  2. 90o
  3. 270o
  4. 0o

Answer : 4

Q27. The power gain in a transistor connected in ……………. arrangement is the highest

  1. common emitter
  2. common base
  3. common collector
  4. none of the above

Answer : 1

Q28. The phase difference between the input and output voltages of a transistor connected in common emitter arrangement is ………………

  1. 0o
  2. 180o
  3. 90o
  4. 270o

Answer : 2

Q29. The voltage gain in a transistor connected in ………………. arrangement is the highest

  1. common base
  2. common collector
  3. common emitter
  4. none of the above

Answer : 3

Q30. As the temperature of a transistor goes up, the base-emitter resistance ……………

  1. decreases
  2. increases
  3. remains the same
  4. none of the above

Answer : 1

Q31. The voltage gain of a transistor connected in common collector arrangement is ………..

  1. equal to 1
  2. more than 10
  3. more than 100
  4. less than 1

Answer : 4

Q32. The phase difference between the input and output voltages of a transistor connected in common collector arrangement is ………………

  1. 180o
  2. 0o
  3. 90o
  4. 270o

Answer : 2

Q33. IC = β IB + ………..

  1. ICBO
  2. IC
  3. ICEO
  4. αIE

Answer : 3

Q34. IC = [α / (1 – α )] IB + ………….

  1. ICEO
  2. ICBO
  3. IC
  4. (1 – α ) IB

Answer : 1

Q35. IC = [α / (1 – α )] IB + […….. / (1 – α )]

  1. ICBO
  2. ICEO
  3. IC
  4. IE

Answer : 1

Q36. BC 147 transistor indicates that it is made of …………..

  1. germanium
  2. silicon
  3. carbon
  4. none of the above

Answer : 2

Q37. ICEO = (………) ICBO

  1. β
  2. 1 + α
  3. 1 + β
  4. none of the above

Answer : 3

Q38. A transistor is connected in CB mode. If it is not connected in CE mode with same bias voltages, the values of IE, IB and IC will …………..

  1. remain the same
  2. increase
  3. decrease
  4. none of the above

Answer : 1

Q39. If the value of α is 0.9, then value of  β is ………..

  1. 9
  2. 0.9
  3. 900
  4. 90

Answer : 4

Q40. In a transistor, signal is transferred from a …………… circuit

  1. high resistance to low resistance
  2. low resistance to high resistance
  3. high resistance to high resistance
  4. low resistance to low resistance

Answer : 2

Q41. The arrow in the symbol of a transistor indicates the direction of ………….

  1. electron current in the emitter
  2. electron current in the collector
  3. hole current in the emitter
  4. donor ion current

Answer : 3

Q42. The leakage current in CE arrangement is ……………. that in CB arrangement

  1. more than
  2. less than
  3. the same as
  4. none of the above

Answer : 1

Q43. A heat sink is generally used with a transistor to …………

  1. increase the forward current
  2. decrease the forward current
  3. compensate for excessive doping
  4. prevent excessive temperature rise

Answer : 4

Q44. The most commonly used semiconductor in the manufacture of a transistor is ………….

  1. germanium
  2. silicon
  3. carbon
  4. none of the above

Answer : 2

Q45. The collector-base junction in a transistor has ……………..

  1. forward bias at all times
  2. reverse bias at all times
  3. low resistance
  4. none of the above

Answer : 2