Multiple Choice Questions and Answers on Transistor Biasing

Multiple Choice Questions and Answers on Transistor Biasing

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. Transistor biasing represents ……………. conditions

1. a.c.
2. d.c.
3. both a.c. and d.c.
4. none of the above

Answer : 2

Q2. Transistor biasing is done to keep ………… in the circuit

1. Proper direct current
2. Proper alternating current
3. The base current small
4. Collector current small

Answer : 1

Q3. Operating point represents …………..

1. Values of I_C and V_CE when signal is applied
2. The magnitude of signal
3. Zero signal values of I_C and V_CE
4. None of the above

Answer : 3

Q4. If biasing is not done in an amplifier circuit, it results in ……………

1. Decrease in the base current
2. Unfaithful amplification
3. Excessive collector bias
4. None of the above

Answer : 2

Q5. Transistor biasing is generally provided by a …………….

1. Biasing circuit
2. Bias battery
3. Diode
4. None of the above

Answer : 1

Q6. For faithful amplification by a transistor circuit, the value of V_BE should ………. for a silicon transistor

1. Be zero
2. Be 0.01 V
3. Not fall below 0.7 V
4. Be between 0 V and 0.1 V

Answer : 3

Q7. For proper operation of the transistor, its collector should have …………

1. Proper forward bias
2. Proper reverse bias
3. Very small size
4. None of the above

Answer : 2

Q8. For faithful amplification by a transistor circuit, the value of V_CE should ……….. for silicon transistor

1. Not fall below 1 V
2. Be zero
3. Be 0.2 V
4. None of the above

Answer : 1

Q9. The circuit that provides the best stabilization of operating point is …………

1. Base resistor bias
2. Collector feedback bias
3. Potential divider bias
4. None of the above

Answer : 3

Q10. The point of intersection of d.c. and a.c. load lines represents …………..

1. Operating point
2. Current gain
3. Voltage gain
4. None of the above

Answer : 1

Q11. An ideal value of stability factor is …………..

1. 100
2. 200
3. More than 200
4. 1

Answer : 4

Q12.  The zero signal I_C is generally ……………… mA in the initial stages of a transistor amplifier

1. 4
2. 1
3. 3
4. More than 10

Answer : 2

Q13. If the maximum collector current due to signal alone is 3 mA, then zero signal collector current should be at least equal to ………..

1. 6 mA
2. mA
3. 3 mA
4. 1 mA

Answer : 3

Q14. The disadvantage of base resistor method of transistor biasing is that it …………

1. Is complicated
2. Is sensitive to changes in ß
3. Provides high stability
4. None of the above

Answer : 2

Q15. The biasing circuit has a stability factor of 50. If due to temperature change, ICBO changes by 1 µA, then I_C will change by …………

1. 100 µA
2. 25 µA
3. 20 µA
4. 50 µA

Answer : 4

Q16. For good stabilsation in voltage divider bias, the current I₁ flowing through R1 and R2 should be equal to or greater than

1. 10 I_B
2. 3 I_B
3. 2 I_B
4. 4 I_B

Answer : 1

Q17. The leakage current in a silicon transistor is about ………… the leakage current in a germanium transistor

1. One hundredth
2. One tenth
3. One thousandth
4. One millionth

Answer : 3

Q18. The operating point is also called the ………….

1. Cut off point
2. Quiescent point
3. Saturation point
4. None of the above

Answer : 2

Q19. For proper amplification by a transistor circuit, the operating point should be located at the ………….. of the d.c. load line

1. The end point
2. Middle
3. The maximum current point
4. None of the above

Answer : 2

Q20. The operating point ………………… on the a.c. load line

1. Also line
2. Does not lie
3. May or may not lie
4. Data insufficient

Answer : 1

Q21. The disadvantage of voltage divider bias is that it has ………….

1. High stability factor
2. Low base current
3. Many resistors
4. None of the above

Answer : 3

Q22. Thermal runaway occurs when ……….

1. Collector is reverse biased
2. Transistor is not biased
3. Emitter is forward biased
4. Junction capacitance is high

Answer : 2

Q23. The purpose of resistance in the emitter circuit of a transistor amplifier is to ………….

1. Limit the maximum emitter current
2. Provide base-emitter bias
3. Limit the change in emitter current
4. None of the above

Answer : 3

Q24. In a transistor amplifier circuit V_CE = V_CB + ……………..

1. V_BE
2. 2V_BE
3. 5 V_BE
4. None of the above

Answer : 1

Q25. The base resistor method is generally used in ………

1. Amplifier circuits
2. Switching circuits
3. Rectifier circuits
4. None of the above

Answer : 2

Q26. For germanium transistor amplifier, V_CE should ………….. for faithful amplification

1. Be zero
2. Be 0.2 V
3. Not fall below 0.7 V
4. None of the above

Answer : 3

Q27. In a base resistor method, if the value of β changes by 50, then collector current will change by a factor ………

1. 25
2. 50
3. 100
4. 200

Answer : 2

Q28.  The stability factor of a collector feedback bias circuit is ……….. that of base resistor bias.

1. The same as
2. More than
3. Less than
4. None of the above

Answer : 3

Q29. In the design of a biasing circuit, the value of collector load R_C is determined by …………

1. V_CE consideration
2. V_BE consideration
3. I_B consideration
4. None of the above

Answer : 1

Q30. If the value of collector current I_C increases, then the value of V_CE …………

1. Remains the same
2. Decreases
3. Increases
4. None of the above

Answer : 2

Q31. If the temperature increases, the value of V_CE …………

1. Remains the same
2. Is increased
3. Is decreased
4. None of the above

Answer : 3

Q32. The stabilisation of operating point in potential divider method is provided by ……….

1. R_E consideration
2. R_C consideration
3. V_CC consideration
4. None of the above

Answer: 1

Q33. The value of V_BE …………….

1. Depends upon I_C to moderate extent
2. Is almost independent of I_C
3. Is strongly dependant on I_C
4. None of the above

Answer : 2

Q34. When the temperature changes, the operating point is shifted due to …….

1. Change in I_CBO
2. Change in V_CC
3. Change in the values of circuit resistance
4. None of the above

Answer : 1

Q35. The value of stability factor for a base resistor bias is …………

1. R_B (β+1)
2. (β+1)R_C
3. (β+1)
4. 1-β

Answer : 3

Q36. In a particular biasing circuit, the value of R_E is about ………

1. 10 kΩ
2. 1 MΩ
3. 100 kΩ
4. 800 Ω

Answer : 4

Q37.  A silicon transistor is biased with base resistor method. If β=100, V_BE =0.7 V, zero signal collector current I_C = 1 mA and V_CC = 6V , what is the value of the base resistor R_B?

1. 105 kΩ
2. 530 kΩ
3. 315 kΩ
4. None of the above

Answer : 2

Q38. In voltage divider bias, V_CC = 25 V; R₁ = 10 kΩ; R₂ = 2.2 V ; R_C = 3.6 V and R_E =1 kΩ. What is the emitter voltage?

1. 6.7 V
2. 5.3 V
3. 4.9 V
4. 3.8 V

Answer : 4

Q39. In the above question (Q38.) , what is the collector voltage?

5. 3 V
6. 8 V
7. 6 V
8. 7 V

Answer : 1

Q40. In voltage divider bias, operating point is 3 V, 2 mA. If V_CC = 9 V, R_C = 2.2 kΩ, what is the value of R_E ?

1. 2000 Ω
2. 1400 Ω
3. 800 Ω
4. 1600 Ω

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:

• Question Bank in Electronics & Communication Engineering by Prem R Chadha
• A Handbook on Electronics Engineering – Illustrated Formulae & Key Theory Concepts