Transistors MCQs Questions Answers PDF: We are going to cover the questions with answers on the same topic.
Transistor MCQs Multiple Choice Questions with Answers PDF
1. What is a transistor?
a. A type of resistor
b. A semiconductor device
c. An insulator
d. A magnetic material
Answer: b. A semiconductor device
2. Who is credited with the invention of the transistor?
a. Nikola Tesla
b. Thomas Edison
c. John Bardeen, Walter Brattain, and William Shockley
d. James Clerk Maxwell
Answer: c. John Bardeen, Walter Brattain, and William Shockley
3. What are the main functions of a transistor in an electronic circuit?
a. Amplification and rectification
b. Filtering and modulation
c. Oscillation and demodulation
d. Amplification, switching, and signal modulation
Answer: d. Amplification, switching, and signal modulation
4. Which type of transistor has three layers of semiconductor material?
a. Bipolar Junction Transistor (BJT)
b. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
c. Junction Field-Effect Transistor (JFET)
d. Insulated Gate Bipolar Transistor (IGBT)
Answer: a. Bipolar Junction Transistor (BJT)
5. In which transistor configuration is the emitter current the sum of collector and base currents?
a. Common Emitter (CE)
b. Common Collector (CC)
c. Common Base (CB)
d. Emitter Follower
Answer: a. Common Emitter (CE)
6. What is the purpose of the base terminal in a transistor?
a. To control the flow of current between the collector and emitter
b. To provide mechanical support to the transistor
c. To act as a heat sink
d. To connect external components
Answer: a. To control the flow of current between the collector and emitter
7. Which material is commonly used as a semiconductor in transistors?
a. Copper
b. Aluminum
c. Silicon
d. Gold
Answer: c. Silicon
8. What is the term for the minimum input voltage required to turn on a transistor in the saturation region?
a. Threshold voltage
b. Breakdown voltage
c. Saturation voltage
d. Cut-off voltage
Answer: a. Threshold voltage
9. Which transistor type is known for its voltage-controlled operation?
a. Bipolar Junction Transistor (BJT)
b. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
c. Junction Field-Effect Transistor (JFET)
d. Darlington Transistor
Answer: b. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
10. What is the symbol for a PNP transistor in a circuit diagram?
a. Arrow pointing out of the emitter
b. Arrow pointing into the emitter
c. Arrow pointing into the collector
d. Arrow pointing out of the collector
Answer: b. Arrow pointing into the emitter
11. What is the primary purpose of the collector terminal in a transistor?
a. To control the flow of current
b. To emit electrons
c. To amplify the input signal
d. To provide a path for the flow of majority charge carriers
Answer: d. To provide a path for the flow of majority charge carriers
12. Which of the following is a common application of transistors in electronic devices?
a. Toasters
b. Digital watches
c. Microwave ovens
d. Incandescent lamps
Answer: b. Digital watches
13. In which transistor configuration does the input and output share a common terminal?
a. Common Emitter (CE)
b. Common Collector (CC)
c. Common Base (CB)
d. Common Drain (CD)
Answer: c. Common Base (CB)
14. What does the term “hFE” represent in the context of transistors?
a. High-Frequency Emitter
b. Hybrid-Function Equivalent
c. Human-Factor Evaluation
d. Common-Base Current Gain
Answer: d. Common-Base Current Gain
15. Which of the following is a disadvantage of bipolar junction transistors (BJTs) compared to MOSFETs?
a. Lower input impedance
b. Greater susceptibility to temperature variations
c. Lower switching speed
d. Higher power consumption
Answer: b. Greater susceptibility to temperature variations
16. What is the function of the gate terminal in a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)?
a. To control the flow of current between the source and drain
b. To provide mechanical stability
c. To amplify the input signal
d. To store electric charge
Answer: a. To control the flow of current between the source and drain
17. What is the primary advantage of Insulated Gate Bipolar Transistors (IGBTs) over conventional BJTs?
a. Higher switching speed
b. Lower power dissipation
c. Higher input impedance
d. Improved thermal stability
Answer: a. Higher switching speed
18. Which region of operation is characterized by both the base-emitter and base-collector junctions of a transistor being forward-biased?
a. Saturation
b. Cut-off
c. Active
d. Inverse
Answer: a. Saturation
19. What is the primary purpose of the body terminal in a Junction Field-Effect Transistor (JFET)?
a. To control the flow of majority carriers
b. To provide a path for the flow of minority carriers
c. To amplify the input signal
d. To store electric charge
Answer: a. To control the flow of majority carriers
20. Which transistor type is often used in high-frequency applications due to its faster switching speed?
a. Bipolar Junction Transistor (BJT)
b. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
c. Junction Field-Effect Transistor (JFET)
d. High Electron Mobility Transistor (HEMT)
Answer: d. High Electron Mobility Transistor (HEMT)
21. Which of the following statements is true regarding NPN and PNP transistors?
a. NPN transistors have a negative collector with respect to the emitter, while PNP transistors have a positive collector.
b. NPN transistors have a positive collector with respect to the emitter, while PNP transistors have a negative collector.
c. NPN and PNP transistors have the same polarity for the collector.
d. NPN and PNP transistors have the same polarity for the emitter.
Answer: a. NPN transistors have a negative collector with respect to the emitter, while PNP transistors have a positive collector.
22. What is the purpose of the Schottky diode in some transistor configurations?
a. To prevent reverse biasing of the collector-base junction
b. To improve thermal stability
c. To protect against overvoltage
d. To increase the breakdown voltage
Answer: c. To protect against overvoltage
23. In a common collector (CC) configuration, what is the voltage relationship between the input and output?
a. In-phase
b. 180 degrees out-of-phase
c. 90 degrees out-of-phase
d. No specific phase relationship
Answer: d. No specific phase relationship
24. What is the primary advantage of complementary symmetry in amplifier design?
a. Higher power dissipation
b. Lower distortion in the output signal
c. Greater susceptibility to noise
d. Reduced bandwidth
Answer: b. Lower distortion in the output signal
25. What is the function of a biasing circuit in a transistor amplifier?
a. To provide stability to the amplifier
b. To amplify the input signal
c. To control the temperature of the transistor
d. To reduce power consumption
Answer: a. To provide stability to the amplifier
26. Which type of transistor has the highest input impedance?
a. NPN bipolar junction transistor (BJT)
b. PNP bipolar junction transistor (BJT)
c. N-channel Metal-Oxide-Semiconductor Field-Effect Transistor (NMOSFET)
d. P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (PMOSFET)
Answer: c. N-channel Metal-Oxide-Semiconductor Field-Effect Transistor (NMOSFET)
27. What is the primary difference between a Darlington transistor and a regular bipolar junction transistor (BJT)?
a. Darlington transistors have two collectors
b. Darlington transistors have higher current gain
c. Regular BJTs have higher input impedance
d. Regular BJTs have two emitters
Answer: b. Darlington transistors have higher current gain
28. What is the role of the substrate in integrated circuits containing transistors?
a. To provide mechanical support
b. To enhance thermal conductivity
c. To isolate individual transistors
d. To store electric charge
Answer: c. To isolate individual transistors
29. Which type of transistor is commonly used in radio-frequency (RF) amplifiers?
a. Bipolar Junction Transistor (BJT)
b. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
c. Junction Field-Effect Transistor (JFET)
d. High Electron Mobility Transistor (HEMT)
Answer: d. High Electron Mobility Transistor (HEMT)
30. What is the term for the phenomenon where a small change in the input signal results in a large change in the output signal in an amplifier?
a. Feedback
b. Hysteresis
c. Distortion
d. Gain
Answer: d. Gain
31. What is the primary purpose of the base resistor in a transistor amplifier circuit?
a. To limit the current flowing into the base
b. To provide bias to the emitter
c. To control the collector current
d. To reduce power dissipation
Answer: a. To limit the current flowing into the base
32. In which configuration does a transistor act as an inverting amplifier?
a. Common Emitter (CE)
b. Common Collector (CC)
c. Common Base (CB)
d. Emitter Follower
Answer: a. Common Emitter (CE)
33. What is the term for the condition when a transistor is not allowing any current to flow between its collector and emitter?
a. Saturation
b. Cut-off
c. Active
d. Breakdown
Answer: b. Cut-off
34. Why are MOSFETs often preferred over BJTs in integrated circuits for digital applications?
a. Lower cost
b. Higher speed and lower power consumption
c. Better thermal stability
d. Higher current gain
Answer: b. Higher speed and lower power consumption
35. What is the primary advantage of using a cascode amplifier configuration?
a. Higher input impedance
b. Lower distortion
c. Increased bandwidth
d. Improved noise performance
Answer: a. Higher input impedance
36. What does the term “transconductance” refer to in the context of transistors?
a. The ability to amplify current
b. The ratio of output voltage to input current
c. The ability to amplify voltage
d. The ratio of output current to input voltage
Answer: d. The ratio of output current to input voltage
37. Which of the following is a characteristic of a Schottky transistor?
a. Low noise performance
b. High breakdown voltage
c. Reduced switching speed
d. Negative temperature coefficient
Answer: a. Low noise performance
38. What is the primary disadvantage of using a Darlington pair configuration?
a. Lower current gain
b. Higher input impedance
c. Reduced bandwidth
d. Higher saturation voltage
Answer: d. Higher saturation voltage
39. In a common collector (CC) configuration, what is the voltage relationship between the input and output?
a. In-phase
b. 180 degrees out-of-phase
c. 90 degrees out-of-phase
d. No specific phase relationship
Answer: d. No specific phase relationship
40. What is the primary purpose of a heat sink in a transistor circuit?
a. To amplify the input signal
b. To improve thermal stability
c. To control the flow of current
d. To dissipate heat and prevent overheating
Answer: d. To dissipate heat and prevent overheating
41. What is the primary advantage of a field-effect transistor (FET) over a bipolar junction transistor (BJT) in terms of input impedance?
a. Higher input impedance
b. Lower input impedance
c. Equal input impedance
d. No significant difference in input impedance
Answer: a. Higher input impedance
42. Which type of transistor is most commonly used in low-power applications such as amplifiers and switches?
a. Bipolar Junction Transistor (BJT)
b. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
c. Junction Field-Effect Transistor (JFET)
d. Insulated Gate Bipolar Transistor (IGBT)
Answer: a. Bipolar Junction Transistor (BJT)
43. What is the purpose of the gate oxide layer in a MOSFET?
a. To provide mechanical support
b. To control the flow of current between the source and drain
c. To store electric charge
d. To enhance thermal stability
Answer: b. To control the flow of current between the source and drain
44. Which region of operation in a transistor corresponds to the condition when the base-emitter junction is forward-biased and the base-collector junction is reverse-biased?
a. Saturation
b. Cut-off
c. Active
d. Inverse
Answer: c. Active
45. What is the primary disadvantage of using a Junction Field-Effect Transistor (JFET) in comparison to other transistor types?
a. Lower input impedance
b. Greater susceptibility to temperature variations
c. Higher power consumption
d. Limited availability
Answer: b. Greater susceptibility to temperature variations
46. What is the function of a bootstrapping capacitor in a transistor amplifier circuit?
a. To provide stability to the amplifier
b. To filter out high-frequency noise
c. To increase the input impedance
d. To enhance the coupling between stages
Answer: c. To increase the input impedance
47. What does the term “VCE” represent in the context of a bipolar junction transistor (BJT)?
a. Voltage Collector Emitter
b. Variable Collector Emitter
c. Voltage Common Emitter
d. Variable Common Emitter
Answer: a. Voltage Collector Emitter
48. In a Common Base (CB) configuration, what is the voltage relationship between the input and output?
a. In-phase
b. 180 degrees out-of-phase
c. 90 degrees out-of-phase
d. No specific phase relationship
Answer: b. 180 degrees out-of-phase
49. Which property of a transistor makes it suitable for amplification applications?
a. Low resistance
b. High capacitance
c. Voltage-controlled current
d. Low temperature coefficient
Answer: c. Voltage-controlled current
50. What is the role of the drain in a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)?
a. To control the flow of majority carriers
b. To provide mechanical support
c. To store electric charge
d. To provide a path for the flow of majority carriers
Answer: d. To provide a path for the flow of majority carriers
51. What is the primary purpose of a load resistor in a transistor circuit?
a. To limit the current flowing into the base
b. To provide bias to the emitter
c. To control the collector current
d. To provide a path for the flow of majority carriers
Answer: c. To control the collector current
52. Which of the following is a characteristic of a PNP bipolar junction transistor (BJT)?
a. The emitter is N-type, and the collector is N-type.
b. The emitter is P-type, and the collector is P-type.
c. The emitter is N-type, and the collector is P-type.
d. The emitter is P-type, and the collector is N-type.
Answer: d. The emitter is P-type, and the collector is N-type.
53. What is the purpose of a decoupling capacitor in a transistor amplifier circuit?
a. To filter out high-frequency noise
b. To provide stability to the amplifier
c. To increase the input impedance
d. To prevent the DC bias from affecting other parts of the circuit
Answer: d. To prevent the DC bias from affecting other parts of the circuit
54. In a common emitter (CE) configuration, what is the voltage relationship between the input and output?
a. In-phase
b. 180 degrees out-of-phase
c. 90 degrees out-of-phase
d. No specific phase relationship
Answer: a. In-phase
55. What is the primary function of the source terminal in a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)?
a. To control the flow of current between the source and drain
b. To provide mechanical support
c. To store electric charge
d. To provide a path for the flow of majority carriers
Answer: a. To control the flow of current between the source and drain
56. What is the purpose of a coupling capacitor in a transistor amplifier circuit?
a. To filter out high-frequency noise
b. To provide stability to the amplifier
c. To increase the input impedance
d. To allow the AC signal to pass while blocking the DC component
Answer: d. To allow the AC signal to pass while blocking the DC component
57. Which of the following is a property of an Insulated Gate Bipolar Transistor (IGBT)?
a. High input impedance
b. High switching speed
c. Voltage-controlled operation
d. Low power dissipation
Answer: b. High switching speed
58. What is the term for the condition when a transistor is fully allowing the flow of current between its collector and emitter?
a. Saturation
b. Cut-off
c. Active
d. Breakdown
Answer: a. Saturation
59. In which transistor configuration does the input signal share a common terminal with the output signal?
a. Common Emitter (CE)
b. Common Collector (CC)
c. Common Base (CB)
d. Emitter Follower
Answer: d. Emitter Follower
60. What is the primary advantage of using MOSFETs over BJTs in power amplifier applications?
a. Higher gain
b. Faster switching speed
c. Lower power dissipation
d. Better thermal stability
Answer: c. Lower power dissipation
61. What is the primary function of the emitter resistor in a transistor amplifier circuit?
a. To limit the current flowing into the base
b. To provide bias to the emitter
c. To control the collector current
d. To stabilize the bias point against temperature variations
Answer: d. To stabilize the bias point against temperature variations
62. Which type of transistor has a structure similar to two back-to-back diodes?
a. Bipolar Junction Transistor (BJT)
b. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
c. Schottky Transistor
d. Darlington Transistor
Answer: a. Bipolar Junction Transistor (BJT)
63. What is the primary advantage of a cascode amplifier configuration?
a. Higher input impedance
b. Lower distortion
c. Increased bandwidth
d. Improved noise performance
Answer: c. Increased bandwidth
64. What is the function of a zener diode in a transistor regulator circuit?
a. To provide stability to the amplifier
b. To prevent reverse biasing of the collector-base junction
c. To maintain a constant output voltage
d. To filter out high-frequency noise
Answer: c. To maintain a constant output voltage
65. Which region of operation in a transistor corresponds to the condition when both the base-emitter and base-collector junctions are reverse-biased?
a. Saturation
b. Cut-off
c. Active
d. Inverse
Answer: b. Cut-off
66. What is the primary advantage of using a push-pull amplifier configuration in audio applications?
a. Higher power dissipation
b. Lower distortion in the output signal
c. Greater susceptibility to noise
d. Reduced bandwidth
Answer: b. Lower distortion in the output signal
67. Which parameter characterizes the ability of a transistor to control the flow of current between the collector and emitter?
a. Voltage gain
b. Current gain
c. Power gain
d. Impedance gain
Answer: b. Current gain
68. What is the purpose of a bypass capacitor in a transistor amplifier circuit?
a. To filter out high-frequency noise
b. To provide stability to the amplifier
c. To increase the input impedance
d. To allow AC signals to bypass the resistor in the emitter circuit
Answer: d. To allow AC signals to bypass the resistor in the emitter circuit
69. In a Common Collector (CC) configuration, what is the voltage relationship between the input and output?
a. In-phase
b. 180 degrees out-of-phase
c. 90 degrees out-of-phase
d. No specific phase relationship
Answer: a. In-phase
70. What is the purpose of a choke coil in a transistor power supply circuit?
a. To provide stability to the amplifier
b. To prevent reverse biasing of the collector-base junction
c. To filter out high-frequency noise
d. To smooth out the rectified AC voltage
Answer: d. To smooth out the rectified AC voltage
71. What is the term for the condition when a transistor is biased near the cutoff region, allowing a small input signal to control a larger output signal?
a. Active mode
b. Saturation
c. Small-signal amplification
d. Class A operation
Answer: c. Small-signal amplification
72. What is the function of a flyback diode in a transistor circuit, such as a relay driver?
a. To protect against overvoltage
b. To filter out high-frequency noise
c. To improve thermal stability
d. To increase the input impedance
Answer: a. To protect against overvoltage
73. In a Darlington pair configuration, how many transistors are connected in series?
a. One
b. Two
c. Three
d. Four
Answer: b. Two
74. What is the purpose of a phase splitter circuit in an audio amplifier using push-pull transistors?
a. To provide stability to the amplifier
b. To prevent reverse biasing of the collector-base junction
c. To maintain a constant output voltage
d. To generate two signals with opposite phases
Answer: d. To generate two signals with opposite phases
75. Which of the following is a characteristic of a JFET (Junction Field-Effect Transistor)?
a. Voltage-controlled operation
b. High input impedance
c. P-type semiconductor material
d. Low switching speed
Answer: b. High input impedance
76. What is the primary role of a transistor in a switching circuit?
a. To provide stability to the amplifier
b. To amplify the input signal
c. To control the flow of current with a small input signal
d. To store electric charge
Answer: c. To control the flow of current with a small input signal
77. In a complementary symmetry amplifier, what types of transistors are used for the NPN and PNP stages?
a. NPN for both stages
b. PNP for both stages
c. NPN for the first stage, PNP for the second stage
d. PNP for the first stage, NPN for the second stage
Answer: c. NPN for the first stage, PNP for the second stage
78. What is the purpose of a bleeder resistor in a transistor power supply circuit?
a. To prevent reverse biasing of the collector-base junction
b. To filter out high-frequency noise
c. To provide stability to the amplifier
d. To discharge the filter capacitor when the power is turned off
Answer: d. To discharge the filter capacitor when the power is turned off
79. What is the primary advantage of using a Darlington pair configuration in a transistor amplifier?
a. Higher current gain
b. Lower distortion
c. Increased bandwidth
d. Improved noise performance
Answer: a. Higher current gain
80. What is the purpose of a crossover distortion compensator in a push-pull transistor amplifier?
a. To provide stability to the amplifier
b. To prevent reverse biasing of the collector-base junction
c. To filter out high-frequency noise
d. To reduce distortion in the output signal
Answer: d. To reduce distortion in the output signal
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