## Multiple Choice Questions and Answers on Transistor Biasing

**Q1. Transistor biasing represents ……………. conditions**

- c.
- c.
- both a.c. and d.c.
- none of the above

**Answer : 2**

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

- Proper direct current
- Proper alternating current
- The base current small
- Collector current small

**Answer : 1**

**Q3. Operating point represents …………..**

- Values of I
_{C }and V_{CE}when signal is applied - The magnitude of signal
- Zero signal values of I
_{C}and V_{CE} - None of the above

**Answer : 3**

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

- Decrease in the base current
- Unfaithful amplification
- Excessive collector bias
- None of the above

**Answer : 2**

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

- Biasing circuit
- Bias battery
- Diode
- None of the above

**Answer : 1**

**Q6. For faithful amplification by a transistor circuit, the value of V _{BE} should ………. for a silicon transistor**

- Be zero
- Be 0.01 V
- Not fall below 0.7 V
- Be between 0 V and 0.1 V

**Answer : 3**

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

- Proper forward bias
- Proper reverse bias
- Very small size
- None of the above

**Answer : 2**

**Q8. For faithful amplification by a transistor circuit, the value of V _{CE }should ……….. for silicon transistor**

- Not fall below 1 V
- Be zero
- Be 0.2 V
- None of the above

**Answer : 1**

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

- Base resistor bias
- Collector feedback bias
- Potential divider bias
- None of the above

**Answer : 3**

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

- Operating point
- Current gain
- Voltage gain
- None of the above

**Answer : 1**

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

- 100
- 200
- More than 200
- 1

**Answer : 4**

**Q12. The zero signal I _{C }is generally ……………… mA in the initial stages of a transistor amplifier**

- 4
- 1
- 3
- 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 ………..**

- 6 mA
- mA
- 3 mA
- 1 mA

**Answer : 3**

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

- Is complicated
- Is sensitive to changes in ß
- Provides high stability
- 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 …………**

- 100 µA
- 25 µA
- 20 µA
- 50 µA

**Answer : 4**

**Q16. For good stabilsation in voltage divider bias, the current I _{1} flowing through R1 and R2 should be equal to or greater than**

- 10 I
_{B} - 3 I
_{B} - 2 I
_{B} - 4 I
_{B}

**Answer : 1**

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

- One hundredth
- One tenth
- One thousandth
- One millionth

**Answer : 3**

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

- Cut off point
- Quiescent point
- Saturation point
- 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**

- The end point
- Middle
- The maximum current point
- None of the above

**Answer : 2**

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

- Also line
- Does not lie
- May or may not lie
- Data insufficient

**Answer : 1**

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

- High stability factor
- Low base current
- Many resistors
- None of the above

**Answer : 3**

**Q22. Thermal runaway occurs when ……….**

- Collector is reverse biased
- Transistor is not biased
- Emitter is forward biased
- Junction capacitance is high

**Answer : 2**

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

- Limit the maximum emitter current
- Provide base-emitter bias
- Limit the change in emitter current
- None of the above

**Answer : 3**

**Q24. In a transistor amplifier circuit V _{CE} = V_{CB }+ ……………..**

- V
_{BE} - 2V
_{BE} - 5 V
_{BE} - None of the above

**Answer : 1**

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

- Amplifier circuits
- Switching circuits
- Rectifier circuits
- None of the above

**Answer : 2**

**Q26. For germanium transistor amplifier, V _{CE }should ………….. for faithful amplification**

- Be zero
- Be 0.2 V
- Not fall below 0.7 V
- 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 ………**

- 25
- 50
- 100
- 200

**Answer : 2**

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

- The same as
- More than
- Less than
- None of the above

**Answer : 3**

**Q29. In the design of a biasing circuit, the value of collector load R _{C} is determined by …………**

- V
_{CE}consideration - V
_{BE}consideration - I
_{B}consideration - None of the above

**Answer : 1**

**Q30. If the value of collector current I _{C} increases, then the value of V_{CE} …………**

- Remains the same
- Decreases
- Increases
- None of the above

**Answer : 2**

**Q31. If the temperature increases, the value of V _{CE} …………**

- Remains the same
- Is increased
- Is decreased
- None of the above

**Answer : 3**

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

- R
_{E}consideration - R
_{C}consideration - V
_{CC}consideration - None of the above

**Answer: 1**

**Q33. The value of V _{BE} …………….**

- Depends upon I
_{C }to moderate extent - Is almost independent of I
_{C} - Is strongly dependant on I
_{C} - None of the above

**Answer : 2**

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

- Change in I
_{CBO} - Change in V
_{CC} - Change in the values of circuit resistance
- None of the above

**Answer : 1**

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

- R
_{B}(β+1) - (β+1)R
_{C} - (β+1)
- 1-β

**Answer : 3**

**Q36. In a particular biasing circuit, the value of R _{E} is about ………**

- 10 kΩ
- 1 MΩ
- 100 kΩ
- 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}?**

- 105 kΩ
- 530 kΩ
- 315 kΩ
- None of the above

**Answer : 2**

**Q38. In voltage divider bias, V _{CC} = 25 V; R_{1} = 10 kΩ; R_{2} = 2.2 V ; R_{C} = 3.6 V and R_{E} =1 kΩ. What is the emitter voltage?**

- 7 V
- 3 V
- V

- 8 V

**Answer : 4**

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

- 3 V
- 8 V
- 6 V
- 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} ?**

- 2000 Ω
- 1400 Ω
- 800 Ω
- 1600 Ω

**Answer : 3**

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