 Floyd Self-test in Transistor Bias Circuits

(Last Updated On: December 8, 2017) This is the Self-test in Chapter 5: Transistor Bias Circuits from the book Electronic Devices Conventional Current Version, 9th edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

Floyd Self-test Chapter 5 Topic Outline

• Floyd Self-test in Transistor Bias Circuits
• Floyd Self-test in The DC Operating Point
• Floyd Self-test in Voltage-Divider Bias
• Floyd Self-test in Other Bias Methods

Start Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. The maximum value of collector current in a biased transistor is

• (a) βdcIB
• (b) IC(sat)
• (c) greater than IE
• (d) IE – IB

2. Ideally, a dc load line is a straight line drawn on the collector characteristic curves between

• (a) the Q-point and cutoff
• (b) the Q-point and saturation
• (c) VCE(cutoff) and IC(sat)
• (d) IB = 0 and IB = IC / βdc

3. If a sinusoidal voltage is applied to the base of a biased npn transistor and the resulting sinusoidal collector voltage is clipped near zero volts, the transistor is

• (a) being driven into saturation
• (b) being driven into cutoff
• (c) operating nonlinearly
• (d) answers (a) and (c)
• (e) answers (b) and (c)

4. The input resistance at the base of a biased transistor depends mainly on

• (a) βdc
• (b) RB
• (c) RE
• (d) βdc and RE

5. In a voltage-divider biased transistor circuit such as in Figure 5–13, RIN(BASE) can generally be neglected in calculations when

• (a) RIN(BASE) > R2
• (b) R2 > 10RIN(BASE)
• (c) RIN(BASE) > 10R2
• (d) R1 << R2

6. In a certain voltage-divider biased npn transistor, VB is 2.95 V. The dc emitter voltage is approximately

• (a) 2.25 V
• (b) 2.95 V
• (c) 3.65 V
• (d) 0.7 V

7. Voltage-divider bias

• (a) cannot be independent of βdc
• (b) can be essentially independent of βdc
• (c) is not widely used
• (d) requires fewer components than all the other methods

8. Emitter bias is

• (a) essentially independent of βdc
• (b) very dependent on
• (c) provides a stable bias point
• (d) answers (a) and (c)

9. In an emitter bias circuit, the emitter current

• (a) is 5.3 mA
• (b) is 2.7 mA
• (c) is 180 mA
• (d) cannot be determined

10. The disadvantage of base bias is that

• (a) it is very complex
• (b) it produces low gain
• (c) it is too beta dependent
• (d) it produces high leakage current

11. Collector-feedback bias is

• (a) based on the principle of positive feedback
• (b) based on beta multiplication
• (c) based on the principle of negative feedback
• (d) not very stable

12. In a voltage-divider biased npn transistor, if the upper voltage-divider resistor (the one connected to VCC) opens,

• (a) the transistor goes into cutoff
• (b) the transistor goes into saturation
• (c) the transistor burns out
• (d) the supply voltage is too high

13. In a voltage-divider biased npn transistor, if the lower voltage-divider resistor (the one connected to ground) opens,

• (a) the transistor is not affected
• (b) the transistor may be driven into cutoff
• (c) the transistor may be driven into saturation
• (d) the collector current will decrease

14. In a voltage-divider biased pnp transistor, there is no base current, but the base voltage is approximately correct. The most likely problem(s) is

• (a) a bias resistor is open
• (b) the collector resistor is open
• (c) the base-emitter junction is open
• (d) the emitter resistor is open
• (e) answers (a) and (c)
• (f) answers (c) and (d)

15. If R1 in Figure 5–25 is open, the base voltage is • (a) +10 V
• (b) 0 V
• (c) 3.13 V
• (d) 0.7 V

16. If R1 is open, the collector current in Figure 5–26 is • (a) 5.17 mA
• (b) 10 mA
• (c) 4.83 mA
• (d) 0 mA