Field-Effect Transistors (FETs) - MCQs

Multiple Choice Questions Topic Outline

• MCQs in Field-Effect Transistors (FETs)
• MCQs in JFET
• MCQs in JFET Characteristics and Parameters
• MCQs in JFET Biasing
• MCQs in The Ohmic Region
• MCQs in MOSFET
• MCQs in MOSFET Characteristics and Parameters
• MCQs in MOSFET Biasing
• MCQs in IGBT

Begin and Good luck!

1. On the drain characteristic curve of a JFET for V_GS = 0, the pinch-off voltage is

• A) below the ohmic area.
• B) between the ohmic area and the constant current area.
• C) between the constant current area and the breakdown region.
• D) above the breakdown region.

2. For a JFET, the value of V_DS at which I_D becomes essentially constant is the

• A) pinch-off voltage.
• B) cutoff voltage.
• C) breakdown voltage.
• D) ohmic voltage.

3. The value of V_GS that makes I_D approximately zero is the

• A) pinch-off voltage.
• B) cutoff voltage.
• C) breakdown voltage.
• D) ohmic voltage.

4. For a JFET, the change in drain current for a given change in gate-to-source voltage, with the drain-to-source voltage constant, is

• A) breakdown.
• B) reverse transconductance.
• C) forward transconductance.
• D) self-biasing.

5. High input resistance for a JFET is due to

• A) a metal oxide layer.
• B) a large input resistor to the device.
• C) an intrinsic layer.
• D) the gate-source junction being reverse-biased.

6. A dual-gated MOSFET is

• A) a depletion MOSFET.
• B) an enhancement MOSFET.
• C) a VMOSFET.
• D) either a depletion or an enhancement MOSFET.

7. Which of the following devices has the highest input resistance?

• A) diode
• B) JFET
• C) MOSFET
• D) bipolar junction transistor

8. A self-biased n-channel JFET has a V_D = 6 V. V_GS = –3 V. Find the value of V_DS.

• A) –3 V
• B) –6 V
• C) 3 V
• D) 6 V

9. Refer to Figure 8-1. Identify the p-channel E-MOSFET.

Figure 8-1

• A) a
• B) b
• C) c
• D) d

10. Refer to Figure 8-1. Identify the n-channel D-MOSFET.

• A) a
• B) b
• C) c
• D) d

11. Refer to Figure 8-1. Identify the n-channel E-MOSFET.

• A) a
• B) b
• C) c
• D) d

12. Refer to Figure 8-1. Identify the p-channel D-MOSFET.

• A) a
• B) b
• C) c
• D) d

13. Refer to Figure 8-2(a). I_D = 6 mA. Calculate the value of V_DS.

Figure 8-2

• A) –6 V
• B) 6 V
• C) 12 V
• D) –3 V

14. Refer to Figure 8-2(b). I^D = 6 mA. Calculate the value of V_DS.

• A) 13.2 V
• B) 10 V
• C) 6.8 V
• D) 0 V

15. Refer to Figure 8-2(c). I_D = 6 mA. Calculate the value of V_DS.

• A) –9 V
• B) 9 V
• C) 6 V
• D) –3 V

16. A JFET data sheet specifies V_GS(off) = –6 V and I_DSS = 8 mA. Find the value of I_D when V_GS = –3 V.

• A) 2 mA
• B) 4 mA
• C) 8 mA
• D) none of the above

17. A JFET data sheet specifies V_GS(off) = –10 V and I_DSS = 8 mA. Find the value of I_D when V_GS = –3 V.

• A) 2 mA
• B) 1.4 mA
• C) 4.8 mA
• D) 3.92 mA

18. Refer to Figure 8-3. Determine the value of V_S.

Figure 8-3

• A) 20 V
• B) 8 V
• C) 6 V
• D) 2 V

19. Refer to Figure 8-3. Calculate the value of V_D.

• A) 20 V
• B) 8 V
• C) 6 V
• D) 2 V

20. Refer to Figure 8-3. What is the value of I_G?

• A) 6 mA
• B) 4 mA
• C) 2 mA
• D) 0 mA

21. Refer to Figure 8-3. Determine the value of V_GS.

• A) –20 V
• B) –8 V
• C) –6 V
• D) –2 V

22. Refer to Figure 8-3. Calculate the value of V_DS.

• A) 0 V
• B) 2 V
• C) 4 V
• D) –2 V

23. The JFET is always operated with the gate-source pn junction _____ -biased.

• A) forward
• B) reverse

24. What three areas are the drain characteristics of a JFET (V_GS = 0) divided into?

• A) ohmic, constant-current, breakdown
• B) pinch-off, constant-current, avalanche
• C) ohmic, constant-voltage, breakdown

25. What type(s) of gate-to-source voltage(s) can a depletion MOSFET (D-MOSFET) operate with?

• A) zero
• B) positive
• C) negative
• D) any of the above

26. The _____ has a physical channel between the drain and source.

• A) D-MOSFET
• B) E-MOSFET
• C) V-MOSFET

27. All MOSFETs are subject to damage from electrostatic discharge (ESD).

• A) true
• B) false

28. Midpoint bias for a D-MOSFET is I_D = _____, obtained by setting V_GS = 0.

• A) I_DSS / 2
• B) I_DSS / 3.4
• C) I_DSS

29. In a self-biased JFET circuit, if V_D = V_DD then ID = _____.

• A) 0
• B) cannot be determined from information above

30. If V_D is less than expected (normal) for a self-biased JFET circuit, then it could be caused by a(n)

• A) open R_G.
• B) open gate lead.
• C) FET internally open at gate.
• D) all of the above

31. The resistance of a JFET biased in the ohmic region is controlled by

• A) V_D.
• B) V_GS.
• C) V_S.
• D) V_DS.

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• Floyd’s Electronic Devices  (Chapter Quiz)

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Power Amplifiers - MCQs

Multiple Choice Questions Topic Outline

• MCQs in Power Amplifiers
• MCQs in Class A Power Amplifier
• MCQs in Class A Power Amplifier
• MCQs in Class AB Push-Pull Amplifiers
• MCQs in Class C Power Amplifier

Begin and Good luck!

1. For BJT power transistors, the collector terminal is always connected to the transistor's case

• A) for easy circuit connection.
• B) to prevent shorts.
• C) because the collector terminal is the critical terminal for heat dissipation.
• D) because the collector terminal is located nearest the case.

2. Quiescent power is the power dissipation of a transistor

• A) with no signal input.
• B) with no load.
• C) under full load.
• D) along the dc load line.

3. A class B amplifier operates in the linear region for

• A) slightly more than 180° of the input cycle.
• B) 360° of the input cycle.
• C) slightly less than 180° of the input cycle.
• D) much less than 180° of the input cycle.

4. In a class AB amplifier, if the V_BE drops are not matched to the diode drops or if the diodes are not in thermal equilibrium with the transistors, this can result in

• A) a current mirror.
• B) diode separation.
• C) crossover distortion.
• D) thermal runaway.

5. Which amplifier is commonly used as a frequency multiplier?

• A) class A
• B) class B
• C) class C
• D) all of the above

6. The least efficient amplifier among all classes is

• A) class B.
• B) class A.
• C) class AB.
• D) class C.

7. A class A amplifier has a voltage gain of 30 and a current gain of 25. What is the power gain?

• A) 30
• B) 25
• C) 1.2
• D) 750

8. You have an application for a power amplifier to operate on FM radio frequencies. The most likely choice would be a _____ amplifier.

• A) class A
• B) class B
• C) class C
• D) class AB

9. A class A amplifier with R_C = 3.3 kΩ and R_E = 1.2 kΩ has a V_CC = 20 V. Find I_C(sat).

• A) 4.4 mA
• B) 6.1 mA
• C) 16.7 mA
• D) 20 mA

10. Refer to Figure 7-1. The dc voltage on the collector, V_C, is

Figure 7-1

• A) 5.4 V.
• B) 6.6 V.
• C) 12 V.
• D) 0 V.

11. Refer to Figure 9-1. This amplifier is operating as a _____ amplifier.

• A) class A
• B) class B
• C) class AB
• D) class C

12. Refer to Figure 7-2. This amplifier is operating as a _____ amplifier.

Figure 7-2

• A) class A
• B) class B
• C) class AB
• D) class C

13. Refer to Figure 7-2. The approximate voltages on the base, collector, and emitter, respectively, are

• A) 0.7 V, 6.8 V, 0 V.
• B) 0 V, 0 V, 0 V.
• C) 0.7 V, 15 V, 0 V.
• D) 0.7 V, 0 V, 15 V.

14. Refer to Figure 7-2. The maximum efficiency of this amplifier is

• A) about 25%.
• B) about 78%.
• C) about 70%.
• D) about 100%.

15. Refer to Figure 7-3. Determine V_B1.

Figure 7-3

• A) 0 V
• B) 0.7 V
• C) 9.3 V
• D) 10.7 V

16. Refer to Figure 7-3. Calculate V_B2.

• A) 0 V
• B) 0.7 V
• C) 9.3 V
• D) 10.7 V

17. Refer to Figure 7-3. You have an oscilloscope across R_L and it shows a zero signal voltage. The problem might be that

• A) C₃ is open.
• B) BE₁ is open.
• C) BE₂ is open.
• D) R₁ is open.

18. Refer to Figure 7-3. You find that this amplifier only shows the negative alternation at the output. The possible trouble might be that

• A) C₃ is shorted.
• B) BE₁ is open.
• C) BE₂ is open.
• D) R₁ is open.

19. Refer to Figure 7-3. You find that there is no output signal. You measure the dc voltage of Q₁ emitter and find it equal to 0 V. The trouble might be

• A) D₁ is shorted.
• B) D₂ is shorted.
• C) R₁ is open.
• D) no trouble, everything is normal.

20. Refer to Figure 7-3. You find that there is an input signal on the base of Q₁ and Q₂. However, there is no output signal. You then measure the dc voltages on Q₂ and find them to be all 0 V. The possible trouble might be

• A) C₃ is shorted.
• B) C₁ is open.
• C) R_L is shorted.
• D) V_CC is 0 V.

21. A class C amplifier has a tank circuit in the output. The amplifier is conducting only 28°. The output voltage is

• A) 0 V.
• B) a dc value equal to V_CC.
• C) a sine wave.
• D) a square wave with a frequency determined by the tank.

22. In practice, the efficiency of a capacitively coupled class A amplifier is about _____%.

• A) 25
• B) 40
• C) 70
• D) 10

23. The Q-point is at cutoff for class _____ operation.

• A) A
• B) B
• C) C
• D) AB

24. Class _____ amplifiers are normally operated in a push-pull configuration in order to produce an output that is a replica of the input.

• A) A
• B) B
• C) C
• D) AB

25. The maximum efficiency of a class B amplifier is _____ percent.

• A) 50
• B) 25
• C) 70
• D) 79

26. A class _____ amplifier is biased slightly above cutoff and operates in the linear region for slightly more than 180º of the input cycle.

• A) A
• B) B
• C) C
• D) AB

27. Which class of amplifier operates in the linear region for only a small part of the input cycle?

• A) A
• B) B
• C) C
• D) AB

28. The principal advantage(s) of MOSFETs over BJTs is (are)

• A) their biasing networks are simpler.
• B) their drive requirements are simpler.
• C) they can be connected in parallel for added drive capability.
• D) all of the above

29. The principal advantage(s) of BJTs over MOSFETs is (are) that

• A) voltage drop across the transistor is important.
• B) they are not as prone to ESD.
• C) both of the above
• D) none of the above

30. The class _____ amplifier is biased below cutoff.

• A) A
• B) AB
• C) B
• D) C

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Bipolar Junction Transistor Amplifiers - MCQs

Multiple Choice Questions Topic Outline

• MCQs in BJT Amplifiers
• MCQs in Amplifier Operation
• MCQs in Transistor AC Models
• MCQs in The Common-Emitter Amplifier
• MCQs in The The Common-Collector Amplifier
• MCQs in The The Common-Base Amplifier
• MCQs in Multistage Amplifiers
• MCQs in The Differential Amplifier
• MCQs in GreenTech Application 6: Wind Power

Begin and Good luck!

1. For the common-emitter amplifier ac equivalent circuit, all capacitors are

• A) effectively shorts.
• B) effectively open circuits.
• C) not connected to ground.
• D) connected to ground.

2. For a common-emitter amplifier, the purpose of the emitter bypass capacitor is

• A) no purpose, since it is shorted out by R_E.
• B) to reduce noise.
• C) to despike the supply voltage.
• D) to maximize amplifier gain.

3. For a common-emitter amplifier, the purpose of swamping is

• A) to minimize gain.
• B) to reduce the effects of r'_e
• C) to maximize gain.
• D) no purpose.

4. An emitter-follower is also known as a

• A) common-emitter amplifier.
• B) common-base amplifier.
• C) common-collector amplifier.
• D) Darlington pair.

5. In a common-base amplifier, the input signal is connected to the

• A) base.
• B) collector.
• C) emitter.
• D) output.

6. The differential amplifier produces outputs that are

• A) common mode.
• B) in-phase with the input voltages.
• C) the sum of the two input voltages.
• D) the difference of the two input voltages.

7. The differential amplifier has

• A) one input and one output.
• B) two inputs and two outputs.
• C) two inputs and one output.
• D) one input and two outputs.

8. The dc emitter current of a transistor is 8 mA. What is the value of r_e?

• A) 320 Ω
• B) 13.3 kΩ
• C) 3.125 Ω
• D) 5.75 Ω

9. Refer to Figure 6-1. Calculate the value of V_B.

Figure 6-1

• A) 5 V
• B) 3.7 V
• C) 20 V
• D) 3 V

10. Refer to Figure 6-1. Find the value of I_E.

• A) 2 mA
• B) 4 mA
• C) 5 mA
• D) 6 mA

11. Refer to Figure 6-1. Determine the value of V_C.

• A) 20 V
• B) 10 V
• C) 5 V
• D) 0 V

12. Refer to Figure 6-1. Find the value of R_in(base).

• A) 420 Ω
• B) 50 kΩ
• C) 940 Ω
• D) 100.8 Ω

13. Refer to Figure 6-1. Calculate the value of R_in(tot).

• A) 37.7 kΩ
• B) 3.77 kΩ
• C) 378 Ω
• D) 2.25 kΩ

14. Refer to Figure 6-1. Determine the value of A_v.

• A) 49.6
• B) 5
• C) 100
• D) 595

15. Refer to Figure 6-1. If an emitter bypass capacitor was installed, determine the value of R_in(base).

• A) 416 Ω
• B) 5 kΩ
• C) 50 kΩ
• D) 500 Ω

16. Refer to Figure 6-1. If an emitter bypass capacitor was installed, calculate the value of R_in(tot).

• A) 378 Ω
• B) 420 Ω
• C) 500 Ω
• D) 40 k Ω

17. Refer to Figure 6-1. If an emitter bypass capacitor was installed, what would the new A_v be?

• A) 4.96
• B) 125
• C) 398
• D) 600

18. An emitter-follower amplifier has an input impedance of 107 kΩ. The input signal is 12 mV. The approximate output voltage is (common-collector)

• A) 8.92 V
• B) 112 mV
• C) 12 mV
• D) 8.9 mV

19. Refer to Figure 6-2. You notice while servicing this amplifier that the output signal at V_out is reduced from normal. The problem could be caused by

Figure 6-2

• A) an open C₃.
• B) an open C₂.
• C) an open base-emitter of Q₂.
• D) a shorted C₂.

20. Refer to Figure 6-2. The output signal from the first stage of this amplifier is 0 V. The trouble could be caused by

• A) an open C₄.
• B) an open C₂.
• C) an open base-emitter of Q₁.
• D) a shorted C₄.

21. A Darlington pair amplifier has

• A) high input impedance and high voltage gain.
• B) low input impedance and low voltage gain.
• C) a voltage gain of about 1 and a low input impedance.
• D) a low voltage gain and a high input impedance.

22. You have a need to apply an amplifier with a very high power gain. Which of the following would you choose?

• A) common-collector
• B) common-base
• C) common-emitter
• D) emitter-follower

23. What is the most important r parameter for amplifier analysis?

• A) r_b′
• B) r_c′
• C) r_e′
• D) none of the above

24. A common-emitter amplifier has _____ voltage gain, _____ current gain, _____ power gain, and _____ input impedance.

• A) high, low, high, low
• B) high, high, high, low
• C) high, high, high, high
• D) low, low, low, high

25. To analyze the common-emitter amplifier, what must be done to determine the dc equivalent circuit?

• A) leave circuit unchanged
• B) replace coupling and bypass capacitors with opens
• C) replace coupling and bypass capacitors with shorts
• D) replace V_CC with ground

26. When the bypass capacitor is removed from a common-emitter amplifier, the voltage gain

• A) increases.
• B) decreases.
• C) has very little effect.

27. A common-collector amplifier has _____ input resistance, _____ current gain, and _____ voltage gain.

• A) high, high, low
• B) high, low, low
• C) high, low, high

28. A Darlington pair provides beta _____ for _____ input resistance.

• A) multiplication, decreased
• B) multiplication, increased
• C) division, decreased

29. The total gain of a multistage amplifier is the _____.

• A) sum of individual voltage gains
• B) sum of dB voltage gains
• C) none of the above

30. What is r_e equal to in terms of h parameters?

• A) h_re / h_oe
• B) (h_re + 1) / h_oe
• C) h_ie – (h_re / h_oe)(1 + h_fe)
• D) h_fe
• E) none of the above

31. The advantage that a Sziklai pair has over a Darlington pair is

• A) higher current gain.
• B) less input voltage is needed to turn it on.
• C) higher input impedance.
• D) higher voltage gain.

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• Floyd’s Electronic Devices  (Chapter Quiz)

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Transistor Bias Circuits - MCQs

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 β_DC result in changes in

• A) I_C.
• B) VC_E.
• 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 I_B = 75 µA, β_DC = 100, V_CC = 20 V, and R_C = 1.5 kΩ?

• A) V_C = 0 V
• B) V_C = 20 V
• C) V_C = 8.75 V
• D) V_C = 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 I_C is maximum.
• D) halfway between cutoff and saturation.

8. Refer to Figure 5-1. The value of I_B 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 I_C is

• A) 10 µA.
• B) 10 mA.
• C) 5 mA.
• D) 50 mA.

10. Refer to Figure 5-1. The value of β_DC is

• A) 5.3.
• B) 53.
• C) 94.
• D) 100.

11. Refer to Figure 5-2. Determine I_C.

Figure 5-2

• A) 5 µA
• B) 5 mA
• C) 0 mA
• D) 10 mA

12. Refer to Figure 5-2. Assume that I_C ≈ I_E. Find V_E.

• A) 5 V
• B) 10 V
• C) 15 V
• D) 2.5 V

13. Refer to Figure 5-2. Assume I_C ≈ I_E. Determine the value of R_C that will allow V_CE 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) R_E 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) R_E 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) R_E 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 V_CE is nearly _____, and I_C = _____.

• A) zero, zero
• B) V_CC, I_C(sat)
• C) zero, I_(sat)
• D) V_CC, 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) β_DCR_C
• B) βdc • (R_C || R_E)
• C) β_DC • r_e′
• D) β_DCR_E

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 β_DC?

• 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 R_C 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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Bipolar Junction Transistors - MCQs

Multiple Choice Questions Topic Outline

• MCQs in Bipolar Junction Transistor (BJT) Structure
• MCQs in Basic BJT Operation
• MCQs in BJT Characteristics and Parameters
• MCQs in The BJT as an Amplifier
• MCQs in The Phototransistor
• MCQs in The BJT as a Switch
• MCQs in Transistor Categories and Packaging
• MCQs in GreenTech Application 4: Solar Power

Begin and Good luck!

1. The dc load line on a family of collector characteristic curves of a transistor shows the

• A) saturation region.
• B) cutoff region.
• C) active region.
• D) all of the above

2. A transistor data sheet usually identifies β_DC as

• A) h_re.
• B) h_fe.
• C) I_C.
• D) V_CE.

3. When a transistor is used as a switch, it is stable in which two distinct regions?

• A) saturation and active
• B) active and cutoff
• C) saturation and cutoff
• D) none of the above

4. For a silicon transistor, when a base-emitter junction is forward-biased, it has a nominal voltage drop of

• A) 0.7 V.
• B) 0.3 V.
• C) 0.2 V.
• D) V_CC.

5. The value of β_DC

• A) is fixed for any particular transistor.
• B) varies with temperature.
• C) varies with I_C.
• D) varies with temperature and I_C.

6. The term BJT is short for

• A) base junction transistor.
• B) binary junction transistor.
• C) both junction transistor.
• D) bipolar junction transistor.

7. A BJT has an I_B of 50 µA and a βDC of 75; I_C is:

• A) 375 mA
• B) 37.5 mA
• C) 3.75 mA
• D) 0.375 mA

8. A certain transistor has I_C = 15 mA and I_B = 167 µA; β_DC is:

• A) 15
• B) 167
• C) 0.011
• D) 90

9. For normal operation of a pnp BJT, the base must be _____ with respect to the emitter and _____ with respect to the collector.

• A) positive, negative
• B) positive, positive
• C) negative, positive
• D) negative, negative

10. A transistor amplifier has a voltage gain of 100. If the input voltage is 75 mV, the output voltage is:

• A) 1.33 V
• B) 7.5 V
• C) 13.3 V
• D) 15 V

11. A 35 mV signal is applied to the base of a properly biased transistor with an r'_e = 8 Ω and R_C = 1 kΩ. The output signal voltage at the collector is:

• A) 3.5 V
• B) 28.57 V
• C) 4.375 V
• D) 4.375 mV

12. Refer to Figure 4-1; the value of V_BE is:

Figure 4-1

• A) 0.6 V
• B) 0.7 V
• C) 1.2 V
• D) 0.079 V

13. Refer to Figure 4-1; the value of V_CE is:

• A) 9.9 V
• B) 9.2 V
• C) 0.7 V
• D) 19.3 V

14. Refer to Figure 4-1; the value of V_BC is:

• A) 9.2 V
• B) 9.9 V
• C) –9.9 V
• D) –9.2 V

15. Refer to Figure 4-2; if V_CE = 0.2 V, I_C(sat) is:

Figure 4-2

• A) 0.05 mA
• B) 2.085 mA
• C) 1.065 mA
• D) 7.4 mA

16. Refer to Figure 4-2. Determine the minimum value of I_B that will produce saturation.

• A) 0.25 mA
• B) 5.325 A
• C) 1.065 A
• D) 10.425 A

17. Refer to Figure 4-2. Determine the minimum value of V_IN from the following that will saturate this transistor.

• A) 13.21 V
• B) 12.51 V
• C) 0.7 V
• D) 9.4 V

18. Refer to Figure 4-3. The value of β_DC = 100 and V_IN = 8 V. Determine I_C(sat).

Figure 4-3

• A) 18 mA
• B) 7.92 mA
• C) 1.8 mA
• D) 8 A

19. Refer to Figure 4-3. In this circuit β_DC = 100 and V_IN = 8 V. The value of R_B that will produce saturation is:

• A) 92 kΩ
• B) 9.1 MΩ
• C) 100 kΩ
• D) 150 kΩ

20. Refer to Figure 4-3. The measured voltage, V_CE, is 20 V. The transistor is in

• A) saturation.
• B) cutoff.
• C) normal.
• D) not enough data.

21. Refer to Figure 4-3. You measure V_CE and find it nearly equal to zero. You now know that the transistor is

• A) operating in cutoff.
• B) operating normally.
• C) operating in saturation.
• D) operating below cutoff.

22. What is the order of doping, from heavily to lightly doped, for each region?

• A) base, collector, emitter
• B) emitter, collector, base
• C) emitter, base, collector
• D) collector, emitter, base

23. What are the two types of bipolar junction transistors?

• A) npn and pnp
• B) pnn and nnp
• C) ppn and nnp
• D) pts and stp

24. Which of the following is true for an npn or pnp transistor?

• A) I_E = I_B + I_C
• B) I_B = I_C+ I_E
• C) I_C = I_B + I_E
• D) none of the above

25. What is the ratio of I_C to I_B?

• A) β_DC
• B) h_FE
• C) α_DC
• D) either β_DC or h_FE, but not α_DC

26. What is the ratio of I_C to I_E?

• A) β_DC
• B) β_DC / (β_DC + 1)
• C) α_DC
• D) either β_DC / (β_DC + 1) or α_DC, but not β_DC

27. In what range of voltages is the transistor in the linear region of its operation?

• A) 0 < V_CE
• B) 0.7 < V_CE < V_CE(max)
• C) V_CE(max) > V_CE
• D) none of the above

28. What does DC vary with?

• A) I_C
• B) ºC
• C) both I_C and ºC
• D) I_C’, but not ºC

29. What is (are) common fault(s) in a BJT-based circuit?

• A) opens or shorts internal to the transistor
• B) open bias resistor(s)
• C) external opens and shorts on the circuit board
• D) all of the above

30. What is (are) general-purpose/small-signal transistors case type(s)?

• A) TO-18
• B) TO-92
• C) TO-39
• D) TO-52
• E) all of the above

31. The magnitude of dark current in a phototransistor usually falls in what range?

• A) mA
• B) μA
• C) nA
• D) pA

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• Floyd’s Electronic Devices  (Chapter Quiz)

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Special-Purpose Diodes - MCQs

Multiple Choice Questions Topic Outline

• MCQs in The Zener Diode
• MCQs in Zener Diode Applications
• MCQs in The Varactor Diode
• MCQs in Optical Diodes
• MCQs in Other Types of Diodes
• MCQs in GreenTech Application 3: Solar Power

Begin and Good luck!

1. The process of emitting photons from a semiconductive material is called

• A) photoluminescence.
• B) gallium arsenide.
• C) electroluminescence.
• D) gallium phosphide.

2. The normal operating region for a zener diode is the

• A) forward-bias region.
• B) reverse-bias region.
• C) zero-crossing region.
• D) reverse-breakdown region.

3. Schottky diodes are also known as

• A) PIN diodes.
• B) hot carrier diodes.
• C) step-recovery diodes.
• D) tunnel diodes.

4. A laser diode normally emits

• A) coherent light.
• B) monochromatic light.
• C) coherent and monochromatic light.
• D) neither coherent nor monochromatic light.

5. An 8.2 V zener has a resistance of 5 Ω. The actual voltage across its terminals when the current is 25 mA is

• A) 8.2 V.
• B) 125 mV.
• C) 8.325 V.
• D) 8.075 V.

6. A 6.2 V zener is rated at 1 watt. The maximum safe current the zener can carry is

• A) 1.61 A.
• B) 161 mA.
• C) 16.1 mA.
• D) 1.61 mA.

7. Refer to Figure 3-1. If the load current increases, I_R will _____ and I_Z will _____.

Figure 3-1

• A) remain the same, increase
• B) decrease, remain the same
• C) increase, remain the same
• D) remain the same, decrease

8. Refer to Figure 3-1. If V_IN attempts to increase, V_R will

• A) increase.
• B) decrease.
• C) remain the same.

9. Refer to Figure 3-1. If V_IN increases, I_Z will

• A) increase.
• B) decrease.
• C) remain the same.

10. Refer to Figure 3-1. If V_IN decreases, I_R will

• A) increase.
• B) decrease.
• C) remain the same.

11. Refer to Figure 3-2. Identify the Schottky diode.

Figure 3-2

• A) a
• B) b
• C) c
• D) d
• E) e

12. Refer to Figure 3-2. Which symbol is correct for a zener diode?

• A) a
• B) b
• C) c
• D) d
• E) e

13. Refer to Figure 3-2. Find the tunnel diode symbol.

• A) a
• B) b
• C) c
• D) d
• E) e

14. Refer to Figure 3-2. Which symbol is correct for a photodiode?

• A) a
• B) b
• C) c
• D) d
• E) e

15. Refer to Figure 3-2. Which symbol is correct for an LED?

• A) a
• B) b
• C) c
• D) d
• E) e

16. An LED is forward-biased. The diode should be on, but no light is showing. A possible trouble might be

• A) the diode is open.
• B) the series resistor is too small.
• C) none. The diode should be off if forward-biased.
• D) the power supply voltage is too high.

17. The Schottky diode is used

• A) in high-power circuits.
• B) in circuits requiring negative resistance.
• C) in very fast-switching circuits.
• D) in power supply rectifiers.

18. A tunnel diode is used

• A) in high-power circuits.
• B) in circuits requiring negative resistance.
• C) in very fast-switching circuits.
• D) in power supply rectifiers.

19. You have an application for a diode to be used in a tuning circuit. A type of diode to use might be

• A) an LED.
• B) a Schottky diode.
• C) a Gunn diode.
• D) a varactor.

20. Zener diodes with breakdown voltages less than 5 V operate predominantly in what type of breakdown?

• A) avalanche
• B) zener
• C) varactor
• D) Schottky

21. Zener diodes with breakdown voltages greater than 5 V operate predominantly in what type of breakdown?

• A) avalanche
• B) zener
• C) varactor
• D) Schottky

22. What type of diode is commonly used in electronic tuners in TVs?

• A) varactor
• B) Schottky
• C) LED
• D) Gunn

23. A varactor is a pn junction diode that always operates in _____-bias and is doped to _____ the inherent capacitance of the depletion region.

• A) forward, maximize
• B) reverse, maximize
• C) reverse, minimize
• D) forward, minimize

24. LEDs are made out of

• A) silicon.
• B) germanium.
• C) gallium.
• D) silicon and germanium, but not gallium.

25. What type of diode maintains a constant current?

• A) LED
• B) zener
• C) current regulator
• D) pin
• E) none of the above

26. What diode operates only with majority carriers?

• A) laser
• B) tunnel
• C) Schottky
• D) step-recovery

27. What kind of diode is formed by joining a doped semiconductor region with a metal?

• A) laser
• B) tunnel
• C) pin
• D) Schottky

28. Which diode employs graded doping?

• A) zener
• B) LED
• C) tunnel
• D) step-recovery

29. What diode is used in seven-segment displays?

• A) zener
• B) LED
• C) laser
• D) Schottky

30. Back-to-back varactor diodes are used for what reason?

• A) over-voltage protection
• B) a wider tuning range
• C) to eliminate harmonic distortion
• D) no reason; only zeners are used in a back-to-back configuration

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• Floyd’s Electronic Devices  (Chapter Quiz)

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Diode Applications - MCQs

Multiple Choice Questions Topic Outline

• MCQs in Diode Operation
• MCQs in Voltage-Current (V-I) Characteristics of a Diode
• MCQs in Diode Models
• MCQs in Half-Wave Rectifiers
• MCQs in Full-Wave Rectifiers
• MCQs in Power Supply Filters and Regulators
• MCQs in Diode Limiters and Clampers
• MCQs in Voltage Multipliers
• MCQs in The Diode Datasheet
• MCQs in GreenTech Application 2: Solar Power

Begin and Good luck!

1. If the ac supply is 60 Hz, what will be the ripple frequency out of the half-wave rectifier?

• A) 30 Hz
• B) 50 Hz
• C) 60 Hz
• D) 120 Hz

2. If the ac supply is 50 Hz, what will be the ripple frequency out of the full-wave rectifier?

• A) 50 Hz
• B) 60 Hz
• C) 100 Hz
• D) 120 Hz

3. A silicon diode in a half-wave rectifier has a barrier potential of 0.7 V. This has the effect of

• A) reducing the peak output voltage by 0.7 V.
• B) increasing the peak output voltage by 0.7 V.
• C) reducing the peak input voltage by 0.7 V.
• D) no effect.

4. In a regulated supply, what term describes how much change occurs in the output voltage for a given change in the input voltage?

• A) load regulation
• B) voltage regulator
• C) line regulation
• D) ripple voltage

5. In a regulated supply, what term describes how much change occurs in the output voltage over a certain range of load current values, from minimum to maximum current?

• A) line regulation
• B) voltage regulator
• C) current regulator
• D) load regulation

6. PIV is which of the following?

• A) peak input voltage
• B) peak inverse voltage
• C) peak immediate voltage
• D) positive input voltage

7. Refer to Figure 2-1. The probable trouble, if any, indicated by these voltages is

Figure 2-1

• A) one of the diodes is open.
• B) a diode is shorted.
• C) an open transformer secondary.
• D) the filter capacitor is shorted.
• E) no trouble exists.

8. Refer to Figure 2-1. If the voltmeter across the transformer reads 0 V, the probable trouble, if any, would be

• A) one of the diodes is open.
• B) a diode is shorted.
• C) an open transformer secondary.
• D) the filter capacitor is shorted.
• E) no trouble exists.

9. Refer to Figure 2-2. Which oscilloscope trace indicates the output from a properly operating half-wave rectifier without a filter?

Figure 2-2.

Assume that each scope has the same settings

• A) a
• B) b
• C) c
• D) d

10. Refer to Figure 2-2. Which oscilloscope trace indicates the output from a properly operating full-wave rectifier with a filter?

• A) a
• B) b
• C) c
• D) d

11. Refer to Figure 2-2. Which oscilloscope trace indicates the output from a full-wave filtered rectifier with an open diode?

• A) a
• B) b
• C) c
• D) d

12. Refer to Figure 2-2. The oscilloscope trace in (b) could represent the output from

• A) a full-wave rectifier (no filter) with an open diode.
• B) a normal half-wave power supply.
• C) a filtered full-wave rectifier with an open diode.
• D) a full-wave rectifier with a shorted diode.

13. Refer to the circuit in Figure 2-3(a). Refer to the output waveforms shown in Figure 2-4 and select the correct approximate output waveform.

Figure 2-3

Figure 2-4

• A) a
• B) b
• C) c
• D) d

14. Refer to the circuit in Figure 2-3(b). Refer to the output waveforms shown in Figure 2-4 and select the correct approximate output waveform.

• A) a
• B) b
• C) c
• D) d

15. Refer to the circuit in Figure 2-3(c). Refer to the output waveforms shown in Figure 2-4 and select the correct approximate output waveform.

• A) a
• B) b
• C) c
• D) d

16. Refer to the circuit in Figure 2-3(d). Refer to the output waveforms shown in Figure 2-4 and select the correct approximate output waveform.

• A) a
• B) b
• C) c
• D) d

17. Refer to Figure 2-5. Which diode arrangement will supply a negative output voltage?

Figure 2-5

• A) a
• B) b
• C) c
• D) d

18. Refer to Figure 2-5. Which diode arrangement will supply a positive output voltage?

• A) a
• B) b
• C) c
• D) d

19. A silicon diode has a voltage to ground of –117 V from the anode. The voltage to ground from the cathode is –117.7 V. The diode is

• A) open.
• B) shorted.
• C) forward-biased.
• D) reverse-biased.

20. The output frequency of a half-wave rectifier is _____ the input frequency.

• A) one-half
• B) twice
• C) equal to
• D) none of the above

21. Each diode in a center-tapped full-wave rectifier is _____ -biased and conducts for _____ of the input cycle.

• A) forward, 90º
• B) reverse, 180º
• C) forward, 180º
• D) reverse, 90º

22. The output frequency of a full-wave rectifier is _____ the input frequency.

• A) one-half
• B) equal to
• C) twice
• D) one-quarter

23. What is the PIV for each diode in a full-wave center-tapped rectifier? Note: V_p(out) = peak output voltage.

• A) Vp_(out) – 0.7 V
• B) Vp_(out) + 0.7 V
• C) 2Vp_(out) – 0.7 V
• D) 2Vp_(out) + 0.7 V

24. In the operation of a half-wave rectifier with a capacitor-input filter, the ripple factor can be lowered by _____ the value of the filter capacitor or _____ the load resistors.

• A) decreasing, decreasing
• B) decreasing, increasing
• C) increasing, decreasing
• D) increasing, increasing

25. What type of diode circuit is used to clip off portions of signal voltages above or below certain levels?

• A) clipper or limiter
• B) clamper
• C) IC voltage regulator
• D) none of the above

26. What type of diode circuit is used to add or restore a dc level to an electrical signal?

• A) clipper or limiter
• B) clamper
• C) IC voltage regulator
• D) none of the above

27. What is the V_RRM (PIV rating) for the 1N4001 rectifier diode?

• A) 50 V
• B) 100 V
• C) 200 V
• D) 400 V
• E) none of the above

28. How many terminals do the 7800 series fixed positive voltage regulators have?

• A) 2
• B) 3
• C) 4
• D) 5
• E) none of the above

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• Floyd’s Electronic Devices  (Chapter Quiz)

Note: Check your works. Diode Applications - MCQs Answers

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Introduction to Semiconductors - MCQs

Multiple Choice Questions Topic Outline

• MCQs in Atom
• MCQs in Materials Used in Electronics
• MCQs in Current in Semiconductors
• MCQs in N-Type and P-Type Semiconductors
• MCQs in The PN Junction
• MCQs in GreenTech Application 1: Solar Power

Begin and Good luck!

1. An atom is made up of

• A) protons.
• B) neutrons.
• C) electrons.
• D) all of the above

2. The maximum number of electrons in each shell of an atom is

• A) 2.
• B) 2n² where n is the number of the shell.
• C) 4.
• D) 8.

3. An n-type semiconductor material

• A) is intrinsic.
• B) has trivalent impurity atoms added.
• C) has pentavalent impurity atoms added.
• D) requires no doping.

4. A diode conducts when it is forward-biased, and the anode is connected to the __________ through a limiting resistor.

• A) positive supply
• B) negative supply
• C) cathode
• D) anode

5. The wide end arrow on a schematic indicates the __________ of a diode.

• A) ground
• B) direction of electron flow
• C) cathode
• D) anode

6. The term bias in electronics usually means

• A) the value of ac voltage in the signal.
• B) the condition of current through a pn junction.
• C) the value of dc voltages for the device to operate properly.
• D) the status of the diode.

7. Doping of a semiconductor material means

• A) that a glue-type substance is added to hold the material together.
• B) that impurities are added to increase the resistance of the material.
• C) that impurities are added to decrease the resistance of the material.
• D) that all impurities are removed to get pure silicon.

8. The forward voltage across a conducting silicon diode is about

• A) 0.3 V.
• B) 1.7 V.
• C) –0.7 V.
• D) 0.7 V.

9. You have an unknown type of diode in a circuit. You measure the voltage across it and find it to be 0.3 V. The diode might be

• A) a silicon diode.
• B) a germanium diode.
• C) a forward-biased silicon diode.
• D) a reverse-biased germanium diode.

10. A reverse-biased diode has the _____ connected to the positive side of the source, and the _____ connected to the negative side of the source.

• A) cathode, anode
• B) cathode, base
• C) base, anode
• D) anode, cathode

11. The movement of free electrons in a conductor is called

• A) voltage.
• B) current.
• C) recombination.
• D) equilibrium.

12. A silicon diode is forward-biased. You measure the voltage to ground from the anode at _____, and the voltage from the cathode to ground at _____.

• A) 0 V, 0.3 V
• B) 2.3 V, 1.6 V
• C) 1.6 V, 2.3 V
• D) 0.3 V, 0 V

13. There is a small amount of current across the barrier of a reverse-biased diode. This current is called

• A) forward-bias current.
• B) reverse breakdown current.
• C) conventional current.
• D) reverse leakage current.

14. The boundary between p-type material and n-type material is called

• A) a diode.
• B) a reverse-biased diode.
• C) a pn junction.
• D) a forward-biased diode.

15. Reverse breakdown is a condition in which a diode

• A) is subjected to a large reverse voltage.
• B) is reverse-biased and there is a small leakage current.
• C) has no current flowing at all.
• D) is heated up by large amounts of current in the forward direction.

16. As the forward current through a silicon diode increases, the voltage across the diode

• A) increases to a 0.7 V maximum.
• B) decreases.
• C) is relatively constant.
• D) decreases and then increases.

17. Which statement best describes an insulator?

• A) A material with many free electrons.
• B) A material doped to have some free electrons.
• C) A material with few free electrons.
• D) No description fits.

18. As the forward current through a silicon diode increases, the internal resistance

• A) increases.
• B) decreases.
• C) remains the same.

19. A silicon diode measures a low value of resistance with the meter leads in both positions. The trouble, if any, is

• A) the diode is open.
• B) the diode is shorted to ground.
• C) the diode is internally shorted.
• D) the diode is working correctly.

20. Single-element semiconductors are characterized by atoms with ____ valence electrons.

• A) 3
• B) 4
• C) 5
• D) 2

21. Effectively, how many valence electrons are there in each atom within a silicon crystal?

• A) 2
• B) 4
• C) 8
• D) 16

22. What occurs when a conduction-band electron loses energy and falls back into a hole in the valence band?

• A) doping
• B) recombination
• C) generation
• D) none of the above

23. What types of impurity atoms are added to increase the number of conduction-band electrons in intrinsic silicon?

• A) bivalent
• B) octavalent
• C) pentavalent
• D) trivalent
• E) none of the above

24. What factor(s) do(es) the barrier potential of a pn junction depend on?

• A) type of semiconductive material
• B) the amount of doping
• C) the temperature
• D) all of the above

25. Under normal conditions a diode conducts current when it is

• A) reverse-biased.
• B) forward-biased.
• C) avalanched.
• D) saturated.

26. For a forward-biased diode, as temperature is _____, the forward current _____ for a given value of forward voltage.

• A) decreased, increases
• B) increased, increases
• C) increased, decreases
• D) decreased, decreases

27. For a forward-biased diode, the barrier potential _____ as temperature increases.

• A) decreases
• B) remains constant
• C) increases

28. An ideal diode presents a(n) _____ when reversed-biased and a(n) _____ when forward-biased.

• A) open, short
• B) short, open
• C) open, open
• D) short, short

29. The most common type of diode failure is a(n) _____.

• A) open
• B) short
• C) resistive

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• Floyd’s Electronic Devices  (Chapter Quiz)

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