Multiple Choice Questions Topic Outline
- MCQs in Transistor Bias Circuits
- MCQs in The DC Operating Point
- MCQs in Voltage-Divider Bias
- MCQs in Other Bias Methods
- MCQs in GreenTech Application 5: Wind Power
Begin and Good luck!
1. Voltage-divider bias has a relatively stable Q-point, as does
- A) base bias.
- B) collector-feedback bias.
- C) both of the above
- D) none of the above
2. Emitter bias requires
- A) only a positive supply voltage.
- B) only a negative supply voltage.
- C) no supply voltage.
- D) both positive and negative supply voltages.
3. Clipping is the result of
- A) the input signal being too large.
- B) the transistor being driven into saturation.
- C) the transistor being driven into cutoff.
- D) all of the above
4. Changes in βDC result in changes in
- A) IC.
- B) VCE.
- C) the Q-point.
- D) all of the above
5. The input resistance at the base of a voltage-divider biased transistor can be neglected
- A) at all times.
- B) only if the base current is much smaller than the current through R2 (the lower bias resistor).
- C) at no time.
- D) only if the base current is much larger than the current through R2 (the lower bias resistor).
6. What is the Q-point for a fixed-bias transistor with IB = 75 µA, βDC = 100, VCC = 20 V, and RC = 1.5 kΩ?
- A) VC = 0 V
- B) VC = 20 V
- C) VC = 8.75 V
- D) VC = 11.25 V
7. Ideally, for linear operation, a transistor should be biased so that the Q-point is
- A) near saturation.
- B) near cutoff.
- C) where IC is maximum.
- D) halfway between cutoff and saturation.
8. Refer to Figure 5-1. The value of IB is
Figure 5-1
- A) 53 µA.
- B) 50 µA.
- C) 50 mA.
- D) 53 mA.
9. Refer to Figure 5-1. The value of IC is
- A) 10 µA.
- B) 10 mA.
- C) 5 mA.
- D) 50 mA.
10. Refer to Figure 5-1. The value of βDC is
- A) 5.3.
- B) 53.
- C) 94.
- D) 100.
11. Refer to Figure 5-2. Determine IC.
Figure 5-2
- A) 5 µA
- B) 5 mA
- C) 0 mA
- D) 10 mA
12. Refer to Figure 5-2. Assume that IC ≈ IE. Find VE.
- A) 5 V
- B) 10 V
- C) 15 V
- D) 2.5 V
13. Refer to Figure 5-2. Assume IC ≈ IE. Determine the value of RC that will allow VCE to equal 10 V.
- A) 1 kΩ
- B) 1.5 kΩ
- C) 2 kΩ
- D) 2.5 kΩ
14. Refer to Figure 5-2. Calculate the current I2.
- A) 32 mA
- B) 3.2 mA
- C) 168 µA
- D) 320 µA
15. Refer to Figure 5-3(a). The most probable cause of trouble, if any, from these voltage measurements would be
Figure 5-3
- A) the base-emitter junction is open.
- B) RE is open.
- C) a short from collector to emitter.
- D) no problems.
16. Refer to Figure 5-3(b). The most probable cause of trouble, if any, from these voltage measurements is
- A) the base-emitter junction is open.
- B) RE is open.
- C) a short from collector to emitter.
- D) no problems.
17. Refer to Figure 5-3(c). The most probable cause of trouble, if any, from these voltage measurements is
- A) the base-emitter junction is open.
- B) RE is open.
- C) a short from collector to emitter.
- D) no problems.
18. Refer to Figure 5-3(d). The most probable cause of trouble, if any, from these voltage measurements is
- A) the base-emitter junction is open.
- B) RE is open.
- C) a short from collector to emitter.
- D) no problems.
19. The most stable biasing technique used is the
- A) voltage-divider bias.
- B) base bias.
- C) emitter bias.
- D) collector bias.
20. At saturation the value of VCE is nearly _____, and IC = _____.
- A) zero, zero
- B) VCC, IC(sat)
- C) zero, I(sat)
- D) VCC, zero
21. The linear (active) operating region of a transistor lies along the load line below _____ and above _____.
- A) cutoff, saturation
- B) saturation, cutoff
22. What is the most common bias circuit?
- A) base
- B) collector
- C) emitter
- D) voltage-divider
23. What is the dc input resistance at the base of a BJT?
- A) βDCRC
- B) βdc • (RC || RE)
- C) βDC • re′
- D) βDCRE
24. Which transistor bias circuit provides good Q-point stability with a single-polarity supply voltage?
- A) base bias
- B) collector-feedback bias
- C) voltage-divider bias
- D) emitter bias
25. Which transistor bias circuit arrangement has poor stability because its Q-point varies widely with βDC?
- A) base bias
- B) collector-feedback bias
- C) voltage-divider bias
- D) emitter bias
26. Which transistor bias circuit arrangement provides good Q-point stability, but requires both positive and negative supply voltages?
- A) base bias
- B) collector-feedback bias
- C) voltage-divider bias
- D) emitter bias
27. Which transistor bias circuit arrangement provides good stability using negative feedback from collector to base?
- A) base bias
- B) collector-feedback bias
- C) voltage-divider bias
- D) emitter bias
28.
FIGURE 5-4
Refer to Figure 5-4. In the voltage-divider biased npn transistor circuit, if RC opens, the transistor is
- A) saturated.
- B) cutoff.
- C) nonconducting.
29. Refer to Figure 5-4. In the voltage-divider biased npn transistor circuit, if R2 opens, the transistor is
- A) saturated.
- B) cutoff.
- C) nonconducting.
30. Refer to Figure 5-4. In the voltage-divider biased npn transistor circuit, if R1 opens, the transistor is
- A) saturated.
- B) cutoff.
- C) nonconducting.
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