Multiple Choice Questions and Answers on Transistors
Multiple Choice Questions and Answers on Transistors
In addition to reading the questions and answers on my site, I would suggest you to check the following, on amazon, as well:
- Question Bank in Electronics & Communication Engineering by Prem R Chadha
- A Handbook on Electronics Engineering – Illustrated Formulae & Key Theory Concepts
Q1. A transistor has …………………
- one pn junction
- two pn junctions
- three pn junctions
- four pn junctions
Answer : 2
Q2. The number of depletion layers in a transistor is …………
- four
- three
- one
- two
Answer : 4
Q3. The base of a transistor is ………….. doped
- heavily
- moderately
- lightly
- none of the above
Answer : 3
Q4. The element that has the biggest size in a transistor is ………………..
- collector
- base
- emitter
- collector-base-junction
Answer : 1
Q5. In a pnp transistor, the current carriers are ………….
- acceptor ions
- donor ions
- free electrons
- holes
Answer : 4
Q6. The collector of a transistor is …………. doped
- heavily
- moderately
- lightly
- none of the above
Answer : 2
Q7. A transistor is a …………… operated device
- current
- voltage
- both voltage and current
- none of the above
Answer : 1
Q8. In a npn transistor, ……………. are the minority carriers
- free electrons
- holes
- donor ions
- acceptor ions
Answer : 2
Q9. The emitter of a transistor is ………………… doped
- lightly
- heavily
- moderately
- none of the above
Answer : 2
Q10. In a transistor, the base current is about ………….. of emitter current
- 25%
- 20%
- 35 %
- 5%
Answer : 4
Q11. At the base-emitter junctions of a transistor, one finds ……………
- a reverse bias
- a wide depletion layer
- low resistance
- none of the above
Answer : 3
Q12. The input impedance of a transistor is ………….
- high
- low
- very high
- almost zero
Answer : 2
Q13. Most of the majority carriers from the emitter ………………..
- recombine in the base
- recombine in the emitter
- pass through the base region to the collector
- none of the above
Answer :3
Q14. The current IB is …………
- electron current
- hole current
- donor ion current
- 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. IC = αIE + ………….
- IB
- ICEO
- ICBO
- βIB
Answer : 3
Q18. The output impedance of a transistor is ……………..
- high
- zero
- low
- very low
Answer : 1
Q19. In a tansistor, IC = 100 mA and IE = 100.2 mA. The value of β is …………
- 100
- 50
- about 1
- 200
Answer : 4
Q20. In a transistor if β = 100 and collector current is 10 mA, then IE is …………
- 100 mA
- 100.1 mA
- 110 mA
- none of the above
Answer : 2
Q21. The relation between β and α is …………..
- β = 1 / (1 – α )
- β = (1 – α ) / α
- β = α / (1 – α )
- β = α / (1 + α )
Answer : 3
Q22. The value of β for a transistor is generally ………………..
- 1
- less than 1
- between 20 and 500
- above 500
Answer : 3
Q23. The most commonly used transistor arrangement is …………… arrangement
- common emitter
- common base
- common collector
- none of the above
Answer : 1
Q24. The input impedance of a transistor connected in …………….. arrangement is the highest
- common emitter
- common collector
- common base
- none of the above
Answer : 2
Q25. The output impedance of a transistor connected in ……………. arrangement is the highest
- common emitter
- common collector
- common base
- none of the above
Answer : 3
Q26. The phase difference between the input and output voltages in a common base arrangement is …………….
- 180o
- 90o
- 270o
- 0o
Answer : 4
Q27. The power gain in a transistor connected in ……………. arrangement is the highest
- common emitter
- common base
- common collector
- 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 ………………
- 0o
- 180o
- 90o
- 270o
Answer : 2
Q29. The voltage gain in a transistor connected in ………………. arrangement is the highest
- common base
- common collector
- common emitter
- none of the above
Answer : 3
Q30. As the temperature of a transistor goes up, the base-emitter resistance ……………
- decreases
- increases
- remains the same
- none of the above
Answer : 1
Q31. The voltage gain of a transistor connected in common collector arrangement is ………..
- equal to 1
- more than 10
- more than 100
- less than 1
Answer : 4
Q32. The phase difference between the input and output voltages of a transistor connected in common collector arrangement is ………………
- 180o
- 0o
- 90o
- 270o
Answer : 2
Q33. IC = β IB + ………..
- ICBO
- IC
- ICEO
- αIE
Answer : 3
Q34. IC = [α / (1 – α )] IB + ………….
- ICEO
- ICBO
- IC
- (1 – α ) IB
Answer : 1
Q35. IC = [α / (1 – α )] IB + […….. / (1 – α )]
- ICBO
- ICEO
- IC
- IE
Answer : 1
Q36. BC 147 transistor indicates that it is made of …………..
- germanium
- silicon
- carbon
- none of the above
Answer : 2
Q37. ICEO = (………) ICBO
- β
- 1 + α
- 1 + β
- 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 …………..
- remain the same
- increase
- decrease
- none of the above
Answer : 1
Q39. If the value of α is 0.9, then value of β is ………..
- 9
- 0.9
- 900
- 90
Answer : 4
Q40. In a transistor, signal is transferred from a …………… circuit
- high resistance to low resistance
- low resistance to high resistance
- high resistance to high resistance
- low resistance to low resistance
Answer : 2
Q41. The arrow in the symbol of a transistor indicates the direction of ………….
- electron current in the emitter
- electron current in the collector
- hole current in the emitter
- donor ion current
Answer : 3
Q42. The leakage current in CE arrangement is ……………. that in CB arrangement
- more than
- less than
- the same as
- none of the above
Answer : 1
Q43. A heat sink is generally used with a transistor to …………
- increase the forward current
- decrease the forward current
- compensate for excessive doping
- prevent excessive temperature rise
Answer : 4
Q44. The most commonly used semiconductor in the manufacture of a transistor is ………….
- germanium
- silicon
- carbon
- none of the above
Answer : 2
Q45. The collector-base junction in a transistor has ……………..
- forward bias at all times
- reverse bias at all times
- low resistance
- none of the above
Answer : 2
Q46. When transistors are used in digital circuits they usually operate in the ………….
- active region
- breakdown region
- saturation and cutoff regions
- linear region
Answer : 3
Q47. Three different Q points are shown on a dc load line. The upper Q point represents the ………….
- minimum current gain
- intermediate current gain
- maximum current gain
- cutoff point
Answer : 3
Q48. A transistor has a of 250 and a base current, IB, of 20
A. The collector current, IC, equals to …………….
- 500 μA
- 5 mA
- 50 mA
- 5 A
Answer : 2
Q49. A current ratio of IC/IE is usually less than one and is called …………
- beta
- theta
- alpha
- omega
Answer : 3
Q50. With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be ……
- open
- infinite
- low resistance
- high resistance
Answer : 3
Q51. In a CE configuration, an emitter resistor is used for ……
- stabilization
- ac signal bypass
- collector bias
- higher gain
Answer : 1
Q52. Voltage-divider bias provides ……….
- an unstable Q point
- a stable Q point
- a Q point that easily varies with changes in the transistor’s current gain
- a Q point that is stable and easily varies with changes in the transistor’s current gain
Answer : 2
Q53. To operate properly, a transistor’s base-emitter junction must be forward biased with reverse bias applied to which junction?
- collector-emitter
- base-collector
- base-emitter
- collector-base
Answer : 4
Q54. The ends of a load line drawn on a family of curves determine ……
- saturation and cutoff
- the operating point
- the power curve
- the amplification factor
Answer : 1
Q55. If VCC = +18 V, voltage-divider resistor R1 is 4.7 k, and R2 is 1500
, then the base bias voltage is ……….
- 8.7 V
- 4.35 V
- 2.9 V
- 0.7 V
Answer: 2
Q56. The C-B configuration is used to provide which type of gain?
- voltage
- current
- resistance
- power
Answer : 1
Q57. The Q point on a load line may be used to determine …………
- VC
- VCC
- VB
- IC
Answer : 3
Q58. A transistor may be used as a switching device or as a ………….
- fixed resistor
- tuning device
- rectifier
- variable resistor
Answer : 4
Q59. If an input signal ranges from 20–40 A (microamps), with an output signal ranging from .5–1.5 mA (milliamps), what is the ac beta?
- 0.05
- 20
- 50
- 500
Answer : 3
Q60. Beta’s current ratio is ……..
- IC/IB
- IC/IE
- IB/IE
- IE/IB
Answer: 1
Q61. A collector characteristic curve is a graph showing ………..
- emitter current (IE) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant
- collector current (IC) versus collector-emitter voltage (VCE) with (VBB) base bias voltage held constant
- collector current (IC) versus collector-emitter voltage (VC) with (VBB) base bias voltage held constant
- collector current (IC) versus collector-emitter voltage (VCC) with (VBB) base bias voltage held constant
Answer: 2
Q62. With low-power transistor packages, the base terminal is usually the ……….
- tab end
- middle
- right end
- stud mount
Answer: 2
Q63. When a silicon diode is forward biased, VBE for a CE configuration is ……..
- voltage-divider bias
- 0.4 V
- 0.7 V
- emitter voltage
Answer: 3
Q64. What is the current gain for a common-base configuration where IE = 4.2 mA and IC = 4.0 mA?
- 16.8
- 1.05
- 0.2
- 0.95
Answer: 4
Q65. With a PNP circuit, the most positive voltage is probably …………
- ground
- VC
- VBE
- VCC
Answer: 1
Q66. If a 2 mV signal produces a 2 V output, what is the voltage gain?
- 0.001
- 0.004
- 100
- 1000
Answer: 4
Q67. Most of the electrons in the base of an NPN transistor flow …………
- out of the base lead
- into the collector
- into the emitter
- into the base supply
Answer: 2
Q68. In a transistor, collector current is controlled by ………..
- collector voltage
- base current
- collector resistance
- all of the above
Answer: 2
Q69. Total emitter current is …………
- IE – IC
- IC + IE
- IB + IC
- IB – IC
Answer: 3
Q70. Often a common-collector will be the last stage before the load; the main function(s) of this stage is to ………….
- provide voltage gain
- provide phase inversion
- provide a high-frequency path to improve the frequency response
- buffer the voltage amplifiers from the low-resistance load and provide impedance matching for maximum power transfer
Answer: 4
Q71. For a CC configuration to operate properly, the collector-base junction should be reverse biased, while forward bias should be applied to …………… junction.
- collector-emitter
- base-emitter
- collector-base
- cathode-anode
Answer: 1
Q72. The input/output relationship of the common-collector and common-base amplifiers is ………..
- 270 degrees
- 180 degrees
- 90 degrees
- 0 degrees
Answer: 4
Q73. If a transistor operates at the middle of the dc load line, a decrease in the current gain will move the Q point ………….
- off the load line
- nowhere
- up
- down
Answer: 4
Q74. Which is the higher gain provided by a CE configuration?
- voltage
- current
- resistance
- power
Answer: 4
Q75. What is the collector current for a CE configuration with a beta of 100 and a base current of 30 A?
- 30
A
- 0.3
A
- 3 mA
- 3 MA
Answer: 3
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In addition to reading the questions and answers on my site, I would suggest you to check the following, on amazon, as well: