Friday, October 31, 2014

Power Amplifiers - MCQs Answers

Filed under:

Answers key for  Power Amplifiers
Below are the answers key for the Multiple Choice Questions (Quiz) in Power Amplifiers from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad.

1. All of the above

2. Between 180º and 360º

3. Class C

4. Class D

5. Class A

6. All of the above

7. Power

8. All of the above

9. Class A

10. Class B

11. None of the above

12. Class C

13. A, AB, B, D

14. 25%

15. N2/N1

16. 3.2 kΩ

17. 40:1

18. 33.3%

19. 50%

20. 78.5%

21. 2

22. 0.636

23. True

24. 70.69%

25. All of the above

26. Quasi-complementary

27. True

28. 8.33%

29. Spectrum analyzer

30. Wave analyzer

31. 150º to 200º

32. Class C

33. 25 W

34. 57.7 W

35. MOSFET

FILL-IN-THE-BLANKS Questions

1. a few W, tens of W

2. All of the above

3. class A

4. 180º

5. Class D

6. 90%

7. less than 100

8. 50%

9. (N1/N2)2

10. the dc

11. –1/(a2RL)

12. difference

13. the least

14. larger, smaller, closer

15. a full-wave

16. VCC

17. Both npn and pnp or nMOS and pMOS

18. higher, lower

19. larger than

20. adding

21. All of the above

22. the higher

23. junction

24. a low

25. class C

Complete List of Chapter Quiz in Electronic Devices and Circuit Theory


Published by: Froyd Wess17:37

Power Amplifiers - MCQs

Filed under:

MCQs for Power Amplifiers
This is the MCQs in Power Amplifiers from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

Multiple Choice Questions Topic Outline

  • MCQs in Introduction—Definitions and Amplifier Types
  • MCQs in Series-Fed Class A Amplifier
  • MCQs in Transformer-Coupled Class A Amplifier
  • MCQs in Class B Amplifier Operation
  • MCQs in Class B Amplifier Circuits
  • MCQs in Amplifier Distortion
  • MCQs in Power Transistor Heat Sinking
  • MCQs in Class C and Class D Amplifiers

Begin and Good luck!

1. Which of the following is (are) power amplifiers?

  • a. Class A
  • b. Class B or AB
  • c. Class C or D
  • d. All of the above

2. By how much does the output signal vary for a class AB power amplifier?

  • a. 360º
  • b. 180º
  • c. Between 180º and 360º
  • d. Less than 180º

3. Which type of power amplifier is biased for operation at less than 180º of the cycle?

  • a. Class A
  • b. Class B or AB
  • c. Class C
  • d. Class D

4. Which type of amplifier uses pulse (digital) signals in its operation?

  • a. Class A
  • b. Class B or AB
  • c. Class C
  • d. Class D

5. Which of the power amplifiers has the lowest overall efficiency?

  • a. Class A
  • b. Class B or AB
  • c. Class C
  • d. Class D

6. Which of the following describe(s) a power amplifier?

  • a. It can handle large power.
  • b. It can handle large current.
  • c. It does not provide much voltage gain.
  • d. All of the above

7. _____ amplifiers primarily provide sufficient power to an output load to drive a speaker from a few watts to tens of watts.

  • a. Small-signal
  • b. Power
  • c. None of the above

8. The main features of a large-signal amplifier is the circuit's ______.

  • a. power efficiency
  • b. maximum power limitations
  • c. impedance matching to the output device
  • d. All of the above

9. This is an example of the output swing for a class _____ amplifier.

clip_image002[33]

  • a. A
  • b. B
  • c. AB
  • d. C
  • e. D

10. This is an example of the output swing for a class _____ amplifier.

clip_image004[11]

  • a. A
  • b. B
  • c. AB
  • d. C
  • e. D

11. Class AB operation is _____ operation.

  • a. similar to class A
  • b. similar to class B
  • c. similar to class C
  • d. None of the above

12. Which operation class is generally used in radio or communications?

  • a. A
  • b. B
  • c. AB
  • d. C
  • e. D

13. Categorize the power efficiency of each class of amplifier, from worst to best.

  • a. A, B, AB, D
  • b. A, AB, D, B
  • c. A, AB, B, D

14. What is the maximum efficiency of a class A circuit with a direct or series-fed load connection?

  • a. 90%
  • b. 78.5%
  • c. 50%
  • d. 25%

15. What is the ratio of the secondary voltage to the primary voltage with the turn ratio in the winding

  • a. N2/N1
  • b. (N1/N2)2
  • c. (N1/N2)1/3
  • d. N1 × N2

16. Calculate the effective resistance seen looking into the primary of a 20:1 transformer connected to an 8- Ω load.

  • a. 3.2 kΩ
  • b. 3.0 kΩ
  • c. 2.8 kΩ
  • d. 1.8 kΩ

17. What transformer turns ratio is required to match an 8-speaker load so that the effective load resistance seen at the primary is 12.8 k?

  • a. 20:1
  • b. 40:1
  • c. 50:1
  • d. 60:1

18. Calculate the efficiency of a transformer-coupled class A amplifier for a supply of 15 V and an output of V(p) = 10 V.

  • a. 25%
  • b. 33.3%
  • c. 50%
  • d. 78.5%

19. The maximum efficiency of a transformer-coupled class A amplifier is _____.

  • a. 25%
  • b. 50%
  • c. 78.5%
  • d. 63.6%

20. What is the maximum efficiency of a class B circuit?

  • a. 90%
  • b. 78.5%
  • c. 50%
  • d. 25%

21. How many transistors must be used in a class B power amplifier to obtain the output for the full cycle of the signal?

  • a. 0
  • b. 1
  • c. 2
  • d. 3

22. In class B operation, at what fraction of VCC should the level of VL(p) be to achieve the maximum power dissipated by the output transistor?

  • a. 0.5
  • b. 0.636
  • c. 0.707
  • d. 1

23. Class B operation is provided when the dc bias leaves the transistor biased just off, the transistor turning on when the ac signal is applied.

  • a. True
  • b. False

24. Calculate the efficiency of a class B amplifier for a supply voltage of VCC = 20 V with peak output voltage of VL(p) = 18 V. Assume RL = 16 Ω.

  • a. 78.54%
  • b. 75%
  • c. 70.69%
  • d. 50%

25. Which of the following is (are) the disadvantage(s) of a class B complementary-symmetry circuit?

  • a. It needs two separate voltage sources.
  • b. There is crossover distortion in the output signal.
  • c. It does not provide exact switching of one transistor off and the other on at the zero-voltage condition.
  • d. All of the above

26. Which of the push-pull amplifiers is presently the most popular form of the class B power amplifier?

  • a. Quasi-complementary
  • b. Transformer-coupled
  • c. Complementary-symmetry
  • d. None of the above

27. nMOS and pMOS transistors can be used for class B.

  • a. True
  • b. False

28. Calculate the harmonic distortion component for an output signal having fundamental amplitude of 3 V and a second harmonic amplitude of 0.25 V.

  • a. 3.83%
  • b. 38.3%
  • c. 83.3%
  • d. 8.33%

29. Which of the following instruments displays the harmonics of a distorted signal?

  • a. Digital multimeter
  • b. Spectrum analyzer
  • c. Oscilloscope
  • d. Wave analyzer

30. Which of the following instruments allows more precise measurement of the harmonic components of a distorted signal?

  • a. Digital multimeter
  • b. Spectrum analyzer
  • c. Oscilloscope
  • d. Wave analyzer

31. What is the maximum temperature rating for silicon power transistors?

  • a. 50º to 80º
  • b. 100º to 110º
  • c. 150º to 200º
  • d. 250º to 300º

32. Which of the power amplifiers is not intended primarily for large-signal or power amplification?

  • a. Class A
  • b. Class B or AB
  • c. Class C
  • d. Class D

33. Determine what maximum dissipation will be allowed for a 70-W silicon transistor (rated at 25ºC) if derating is required above 25ºC by a derating factor of 0.6 W/ºC at a case temperature of 100º.

  • a. 25 W
  • b. 30 W
  • c. 35 W
  • d. 40 W

34. A silicon power transistor is operated with a heat sink (θSA = 1.5ºC/W). The transistor, rated at 150 W (25ºC), has θJC = 0.5º C/W, and the mounting insulation has θCS = 0.6 ºC/W. What is the maximum power that can be dissipated if the ambient temperature is 50ºC and TJmax = 200 ºC?

  • a. 61.5 W
  • b. 60.0 W
  • c. 57.7 W
  • d. 55.5 W

35. Which of the following transistors has been quite popular as the driver device for class D amplification?

  • a. BJT
  • b. FET
  • c.UJT
  • d. MOSFET


FILL-IN-THE-BLANKS

1. Power amplifiers primarily provide sufficient power to an output load, typically from _____ to _____.

  • A. a few kW, tens of kW
  • B. 500 W, 1 kW
  • C. 100 W, 500 W
  • D. a few W, tens of W

2. The main feature(s) of a large-signal amplifier is (are) the _____.

  • A. circuit's power efficiency
  • B. maximum amount of power that the circuit is capable of handling
  • C. impedance matching to the output
  • D. All of the above

3. In _____ power amplifiers, the output signal varies for a full 360º of the cycle.

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

4. In class B power amplifiers, the output signal varies for _____ of the cycle.

  • A. 360º
  • B. 180º
  • C. between 180º and 360º
  • D. less than 180º

5. _____ amplifiers have the highest overall efficiency.

  • A. Class A
  • B. Class B or AB
  • C. Class C
  • D. Class D

6. Class D operation can achieve power efficiency of over _____.

  • A. 90%
  • B. 78.5%
  • C. 50%
  • D. 25%

7. The beta of a power transistor is generally _____.

  • A. more than 200
  • B. 100 to 200
  • C. less than 100
  • D. 0

8. A form of class A amplifier having maximum efficiency of _____ uses a transformer to couple the output signal to the load.

  • A. 90%
  • B. 78.5%
  • C. 50%
  • D. 25%

9. The reflected impedance seen from one side of the transformer to the other side is _____.

  • A. N1/N2
  • B. (N1/N2)2
  • C. (N1/N2)1/3
  • D. N1× N2

10. In a class A transformer-coupled power amplifier, _____ winding resistance of the transformer determine(s) the dc load line for the circuit.

  • A. the ac
  • B. the dc
  • C. both the ac and dc
  • D. neither the ac nor dc

11. The slope of the ac load line in the class A transformer-coupled transistor is _____.

  • A. –1/RL (load resistor)
  • B. 1/(a2RL)
  • C. –1/(a2RL)
  • D. 1/RL

12. The amount of power dissipated by the transistor is the _____ of that drawn from the dc supply (set by the bias point) and the amount delivered to the ac load.

  • A. product
  • B. difference
  • C. average

13. A class A amplifier dissipates _____ power when the load is drawing maximum power from the circuit.

  • A. the least
  • B. about the same
  • C. the most
  • D. None of the above

14. In a class A transformer-coupled amplifier, the _____ the value of VCEmax and the _____ the value of VCEmin, the _____ the efficiency to (from) the theoretical limit of 50%.

  • A. larger, smaller, farther
  • B. larger, smaller, closer
  • C. smaller, larger, closer
  • D. None of the above

15. In class B operation, the current drawn from a single power supply has the form of _____ rectified signal.

  • A. a full-wave
  • B. a half-wave
  • C. both a full-wave and a half-wave
  • D. None of the above

16. The highest efficiency is obtained in class B operation when the level of VL(p) is equal to _____.

  • A. 0.25VCC
  • B. 0.50VCC
  • C. VCC
  • D. 2VCC

17. _____ transistors can be used to build a class B amplifier.

  • A. npn and pnp
  • B. nMOS and pMOS
  • C. Both npn and pnp or nMOS and pMOS
  • D. None of the above

18. The complementary Darlington-connected transistor for a class B amplifier provides _____ output current and _____ output resistance.

  • A. higher, higher
  • B. higher, lower
  • C. lower, lower
  • D. lower, higher

19. The fundamental component is typically _____ any harmonic component.

  • A. larger than
  • B. the same as
  • C. smaller than
  • D. None of the above

20. In Fourier technique, any periodic distorted waveform can be represented by _____ the fundamental and all harmonic components.

  • A. multiplying
  • B. subtracting
  • C. dividing
  • D. adding

21. Improvement in production techniques of power transistors have _____.

  • A. produced higher power ratings in small-sized packaging cases
  • B. increased the maximum transistor breakdown voltage
  • C. provided faster-switching power transistors
  • D. All of the above

22. The greater the power handled by the power transistor, _____ the case temperature.

  • A. the higher
  • B. the lower
  • C. there is no change in
  • D. None of the above

23. The _____ has the hottest temperature in a power transistor.

  • A. heat sink
  • B. case
  • C. junction
  • D. None of the above

24. A heat sink provides _____ thermal resistance between case and air.

  • A. a high
  • B. a low
  • C. the same
  • D. None of the above

25. A _____ power amplifier is limited to use at one fixed frequency.

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

Complete List of Chapter Quiz in Electronic Devices and Circuit Theory

Check your work.


Published by: Froyd Wess17:34

Op-Amp Applications - MCQs Answers

Filed under:

Answers key for  Op-Amp Applications
Below are the answers key for the Multiple Choice Questions (Quiz) in Operational Amplifiers Applications from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad.

1. –0.125 V

2. 1.1 V

3. 6.12 mV

4. 1 V

5. 3.02 V

6. 0.075 V

7. –0.075 V

8. 0.168 V

9. 50 kΩ

10. False

11. True

12. –6.45 V

13. –6.6 V

14. –4 V

15. –6.6 V

16. 2 V

17. –10(V2 – V1)

18. –4 V

19. 0 V

20. 12 V

21. 0 V

22. 2 V

23. –2 V

24. 3

25. 2

26. 1

27. 1

28. 5 mA

29. 5.25 V

30. All of the above

31. instrumentation amplifier

32. 1.273 kHz

33. fOL = 318.3 Hz, fOH = 318.3 Hz

34. low-pass

35. False

FILL-IN-THE-BLANKS Questions

1. smaller than

2. All of the above

3. product

4. Both inverting and noninverting op-amp circuits can be used to

5. several inputs and one output

6. 1

7. in phase

8. very high

9. low

10. All of the above

11. The output voltage depends on the input current.

12. Both inverting and noninverting op-amp circuits

13. in phase

14. both ac and dc

15. All of the above

16. high, resistor

17. the ac

18. difference between the two inputs

19. op-amp

20. All of the above

21. All of the above

22. bandpass

23. either –20 dB/decade or –6 dB/octave

24. either –40 dB per decade or –12 dB per octave

25. a high-pass and a low-pass

Complete List of Chapter Quiz in Electronic Devices and Circuit Theory


Published by: Froyd Wess15:39

Op-Amp Applications - MCQs

Filed under:

MCQs for Op-Amp Applications
This is the MCQs in Operational Amplifiers Applications from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

Multiple Choice Questions Topic Outline

  • MCQs in Constant-Gain Multiplier
  • MCQs in Voltage Summing
  • MCQs in Voltage Buffer
  • MCQs in Controller Sources
  • MCQs in Instrumentation Circuits
  • MCQs in Active Filters

Begin and Good luck!

1. Determine the output voltage for this circuit with a sinusoidal input of 2.5 mV.

clip_image002[31]

  • a. –0.25 V
  • b. –0.125 V
  • c. 0.25 V
  • d. 0.125 V

2. Calculate the input voltage for this circuit if Vo = –11 V.

clip_image004

  • a. 1.1 V
  • b. –1.1 V
  • c. –1 V
  • d. 1 V

3. Calculate the output voltage.

clip_image006

  • a. –6.00 mV
  • b. 6.0 mV
  • c. 6.12 mV
  • d. –6.12 Mv

4. Calculate the input voltage when Vo = 11 V.

clip_image008

  • a. 1.1 V
  • b. –1.1 V
  • c. –1 V
  • d. 1 V

5. Calculate the output voltage.

clip_image010

  • a. 3.02 V
  • b. 2.03 V
  • c. 1.78 V
  • d. 1.50 V

6. Calculate the output of the first-stage op-amp when V1 = 25 mV.

clip_image012[11]

  • a. –1.05 V
  • b. 0.075 V
  • c. 0.06 V
  • d. 4.2 V

7. Calculate the output of the second stage op-amp if V1 = 25 mV.

clip_image014

  • a. –0.075 V
  • b. 0.525 V
  • c. 0.06 V
  • d. 4.2 V

8. Calculate the input voltage if the final output is 10.08 V.

clip_image016

  • a. –1.05 V
  • b. 0.525 V
  • c. 0.168 V
  • d. 4.2 V

9. Determine the value of Rf (assuming that all have the same value).

clip_image018

  • a. 500 kΩ
  • b. 50 kΩ
  • c. 25 kΩ
  • d. 5 kΩ

10. When a number of stages are connected in parallel, the overall gain is the product of the individual stage gains.

  • a. True
  • b. False

11. A number of op-amp stages can be used to provide separate gains.

  • a. True
  • b. False

12. Calculate the output voltage if V1 = V2 = 0.15 V.

clip_image020

  • a. 0 V
  • b. 4.65 V
  • c. 6.45 V
  • d. –6.45 V

13. Calculate the output voltage if V1 = –3.3 V and V2 = 0.8 V

clip_image022

  • a. 0 V
  • b. –6.6 V
  • c. –4 V
  • d. 2 V

14. Calculate the output voltage if V1 = 33 mV and V2 = 02 mV.

clip_image024

  • a. 0 V
  • b. –6.6 V
  • c. –4 V
  • d. 2

15. Calculate the output voltage if V1 = 0 V and V2 = 0.2 V.

clip_image026

  • a. 0 V
  • b. –6.6 V
  • c. –4 V
  • d. 2 V

16. Calculate the output voltage if V1 = –0.2 V and V2 = 0 V.

clip_image028

  • a. 0 V
  • b. –6.6 V
  • c. –4 V
  • d. 2 V

17. Determine the output voltage.

clip_image030

  • a. 10(V2 – Vi)
  • b. –10(V2 – V1)
  • c. –10(V1 – V2)
  • d. None of the above

18. Calculate the output voltage if V1 = 300 mV and V2 = 700 mV.

clip_image032

  • a. 0 V
  • b. –12 V
  • c. 12 V
  • d. –4 V

19. Calculate the output voltage if V1 = V2 = 700 mV.

clip_image034

  • a. 0 V
  • b. –12 V
  • c. 12 V
  • d. –8 V

20. Refer to Fig. Calculate the output voltage Vo if V1 = –V2 = 300 mV.

clip_image036

  • a. 0 V
  • b. –12 V
  • c. 12 V
  • d. –8 V

21. Determine the output voltage when V1 = V2 = 1 V.

clip_image038

  • a. 0 V
  • b. –2 V
  • c. 1 V
  • d. 2 V

22. Determine the output voltage when V1 = –V2 = 1 V.

clip_image040

  • a. 0 V
  • b. –2 V
  • c. 1 V
  • d. 2 V

23. Determine the output voltage when V1 = –V2 = –1 V.

clip_image042

  • a. 0 V
  • b. –2 V
  • c. 1 V
  • d. 2 V

24. How many op-amps are required to implement this equation?

clip_image044

  • a. 2
  • b. 3
  • c. 4
  • d. 1

25. How many op-amps are required to implement this equation?

clip_image046

  • a. 2
  • b. 3
  • c. 4
  • d. 1

26. How many op-amps are required to implement this equation?

clip_image048

  • a. 2
  • b. 3
  • c. 4
  • d. 1

27. How many op-amps are required to implement this equation?

Vo = V1

  • a. 2
  • b. 3
  • c. 4
  • d. 1

28. Calculate IL for this circuit.

clip_image050

  • a. 3 mA
  • b. 4 mA
  • c. 5 mA
  • d. 6 mA

29. Calculate the output voltage for this circuit when V1 = 2.5 V and V2 = 2.25 V.

clip_image052

  • a. –5.25 V
  • b. 2.5 V
  • c. 2.25 V
  • d. 5.25 V

30. An example of an instrumentation circuit is a(n) _____.

  • a. dc voltmeter
  • b. display driver
  • c. ac voltmeter
  • d. All of the above

31. This circuit is an example of a(n)________.

clip_image054

  • a. dc voltmeter
  • b. display driver
  • c. instrumentation amplifier
  • d. None of the above

32. Calculate the cut-off frequency of a first-order low-pass filter for R1 = 2.5 kΩ and C1 = 0.05 μF.

  • a. 1.273 kHz
  • b. 12.73 kHz
  • c. 127.3 kHz
  • d. 127.30 Hz

33. Calculate the cutoff frequencies of a bandpass filter with R1 = R2 = 5 kΩ and C1 = C2 = 0.1 μF.

  • a. fOL = 318.3 Hz, fOH = 318.3 Hz
  • b. fOL = 636.6 Hz, fOH = 636.6 Hz
  • c. fOL = 318.3 Hz, fOH = 636.6 Hz
  • d. fOL = 636.6 Hz, fOH = 318.3

34. A filter that provides a constant output from dc up to a cut-off frequency and passes no signal above that frequency is called a _____ filter.

  • a. low-pass
  • b. high-pass
  • c. bandpass

35. A difference between a passive filter and an active filter is that a passive filter uses amplifier(s), but an active filter does not.

  • A. True
  • B. False


FILL-IN-THE-BLANKS

1. The level of the output voltage of an op-amp circuit is always _____ the level of VCC.

  • A. larger than
  • B. the same as
  • C. smaller than
  • D. None of the above

2. The input to an op-amp can be a(n) _____.

  • A. dc source
  • B. ac source
  • C. combination of ac and dc sources
  • D. All of the above

3. When a number of stages are connected in series, the overall gain is the _____ of the individual stage gains.

  • A. sum
  • B. product
  • C. difference
  • D. average

4. _____ build a multistage connection.

  • A. Only an inverting op-amp circuit must be used to
  • B. Only a noninverting op-amp circuit must be used to
  • C. Both inverting and noninverting op-amp circuits can be used to
  • D. Neither inverting nor noninverting op-amp circuits must be used to

5. A voltage summing amplifier has _____.

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

6. The voltage gain of a voltage buffer is _____ .

  • A. 1
  • B. 0
  • C. –1
  • D. –5

7. The output voltage of a voltage buffer is _____ with the input voltage.

  • A. in phase
  • B. 45º out of phase
  • C. 90º out of phase
  • D. 180º out of phase

8. The input impedance of a voltage buffer is _____.

  • A. very low
  • B. low
  • C. high
  • D. very high

9. The output impedance of a voltage buffer is _____.

  • A. very low
  • B. low
  • C. high
  • D. very high

10. Op-amps can be used to form _____ circuit(s).

  • A. voltage-controlled voltage source
  • B. voltage-controlled current source
  • C. current-controlled voltage source
  • D. All of the above

11. _____ in a current-controlled voltage source circuit.

  • A. The input current depends on the output voltage
  • B. The input current depends on the input voltage source
  • C. The output voltage depends on the input current.
  • D. The output current depends on the output voltage source

12. _____ can be used as a voltage-controlled voltage source.

  • A. Only an inverting op-amp circuit
  • B. Only a noninverting op-amp circuit
  • C. Neither inverting nor noninverting op-amp circuits
  • D. Both inverting and noninverting op-amp circuits

13. In a current-controlled voltage source using the inverting op-amp circuit, the controlled output current is _____ with the input voltage source.

  • A. in phase
  • B. 45º out of phase
  • C. 90º out of phase
  • D. 180º out of phase

14. Op-amp circuits are used in _____ voltmeters.

  • A. only dc
  • B. only ac
  • C. both ac and dc
  • D. neither ac nor dc

15. In a current-controlled current source, the controlled current Io depends on _____.

  • A. I1
  • B. R1
  • C. R2
  • D. All of the above

16. In a dc millivoltmeter, the amplifier provides a meter with _____ input impedance and a scale factor dependent on _____ value and accuracy.

  • A. high, resistor
  • B. low, resistor
  • C. high, capacitor
  • D. None of the above

17. In a millivoltmeter, the diodes and the capacitor are used in _____ parts of the circuit.

  • A. the dc
  • B. the ac
  • C. both the dc and ac
  • D. neither the dc nor ac

18. In an instrumentation amplifier, the output voltage is based on the _____ times a scale factor.

  • A. summation of the two inputs
  • B. product of the two inputs
  • C. difference between the two inputs
  • D. None of the above

19. A(n) _____ is not a component of a passive filter.

  • A. op-amp
  • B. capacitor
  • C. inductor
  • D. resistor

20. An active circuit is composed of a(n) _____.

  • A. resistor
  • B. capacitor
  • C. op-amp
  • D. All of the above

21. A low-pass filter _____.

  • A. provides a constant output up to the cutoff frequency
  • B. passes frequencies from zero up to the cutoff frequency
  • C. rejects all frequencies above the cutoff frequency
  • D. All of the above

22. A filter that passes signals that are above one ideal cutoff frequency and below a second cutoff frequency is called _____.

  • A. low-pass
  • B. high-pass
  • C. bandpass
  • D. band reject

23. The roll-off for a first-order high-pass filter is _____.

  • A. –20 dB/decade
  • B. –6 dB/octave
  • C. either –20 dB/decade or –6 dB/octave
  • D. None of the above

24. The roll-off for a second-order high-pass filter is _____.

  • A. either –20 dB per decade or –6 dB per octave
  • B. either –40 dB per decade or –12 dB per octave
  • C. either –60 dB per decade or –18 dB per octave
  • D. None of the above

25. A bandpass filter uses _____ circuit.

  • A. a high-pass
  • B. a low-pass
  • C. a high-pass and a low-pass
  • D. neither a low-pass nor a high-pass

Complete List of Chapter Quiz in Electronic Devices and Circuit Theory

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Operational Amplifiers - MCQs Answers

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Answers key for  Operational Amplifiers
Below are the answers key for the Multiple Choice Questions (Quiz) in Operational Amplifiers from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad.

1. All of the above

2. single-ended input

3. double-ended (differential) input

4. double-ended output

5. common-mode operation

6. Common-mode

7. Emitters

8. Bipolar and MOSFET

9. bipolar, MOSFET, BiMOS

10. Virtually zero

11. Virtually zero

12. 1

13. –10

14. 11

15. 1

16. 50 mV

17. –1.5 V

18. –1 / RC

19. True

20. inverting amplifier

21. integrator

22. differentiator

23. Both an input offset voltage, VIO and an input offset current, IIO

24. –20 dB / decade or –6 dB / octave

25. All of the above

26. 1

27. 15 Hz

28. 5 V/ms

29. 250

30. 0.00375

31. The sum of the differential gain times the difference input voltage and the common-mode gain times the common input voltage.

32. The differential gain times twice the input signal.

33. The common-mode gain times the input signal.

34. V i1 = –V i2 = 0.50 V

35. Vi1 = –Vi2 = 0.50 V

FILL-IN-THE-BLANKS Questions

1. very high, wide

2. high, low

3. 180º

4. either an input is applied between the two input terminals or two separate signals are applied to the input terminals

5. outputs from both output terminals, which have opposite polarities

6. highly, slightly

7. single-ended

8. double-ended

9. common-mode

10. very large, very small

11. BiFET

12. CMOS

13. CMOS

14. infinite, zero, infinite

15. inverting

16. capacitor

17. V/ms

18. All of the above

19. increases, increases

20. decreases, decreases

21. None of the above

22. the input offset voltage and input offset current

23. closed-loop gain

24. average of the sum

25. Ad / Ac

26. infinite, larger

Complete List of Chapter Quiz in Electronic Devices and Circuit Theory


Published by: Froyd Wess11:38

Operational Amplifiers - MCQs

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MCQs for Operational Amplifiers
This is the MCQs in Operational Amplifiers from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

Multiple Choice Questions Topic Outline

  • MCQs in Differential Amplifier circuit
  • MCQs in BiFET, BiMOS, and CMOS Differential Amplifier circuit
  • MCQs in Op-Amp Basics
  • MCQs in Practical Op-Amp Circuits
  • MCQs in Op-Amp Specifications—DC Offset Parameters
  • MCQs in Op-Amp Specifications—Frequency Parameters
  • MCQs in Op-Amp Unit Specifications
  • MCQs in Differential and Common-Mode Operation

Begin and Good luck!

1. In which of the following are operational amplifiers (op-amps) used?

  • a. Oscillators
  • b. Filters
  • c. Instrumentation circuits
  • d. All of the above

2. This circuit is an example of a _____.

clip_image002

  • a. single-ended input
  • b. double-ended (differential) input
  • c. double-ended output
  • d. common-mode operation

3. This circuit is an example of a _____.

clip_image003

  • a. single-ended input
  • b. double-ended (differential) input
  • c. double-ended output
  • d. common-mode operation

4. This circuit is an example of a _____.

clip_image005

  • a. single-ended input
  • b. double-ended (differential) input
  • c. double-ended output
  • d. common-mode operation

5. This circuit is an example of a _____.

clip_image007

  • a. single-ended input
  • b. double-ended (differential) input
  • c. double-ended output
  • d. common-mode operation

6. In which of the following operations is the resulting output signal of the differential amplifier near zero?

  • a. Single-ended
  • b. Double-ended
  • c. Common-mode
  • d. None of the above

7. In the differential amplifier circuit, which of the following terminals are connected together?

  • a. Bases
  • b. Collectors
  • c. One base to another collector
  • d. Emitters

8. Which of the following circuits is referred to as a BiMOS circuit?

  • a. Bipolar and FET
  • b. Bipolar and MOSFET
  • c. Opposite-type MOSFETs
  • d. None of the above

9. An IC unit made using both _____ and _____ transistors is called a _____ circuit.

  • a. bipolar, MOSFET, BiFET
  • b. bipolar, MOSFET, BiMOS
  • c. TTL, MOSFET, TailFET

10. What is the level of the voltage between the input terminals of an op-amp?

  • a. Virtually zero
  • b. 5 V
  • c. 18 V
  • d. 22 V

11. What is the level of the current through the amplifier input(s) to ground in an op-amp?

  • a. Virtually zero
  • b. 1.7 mA
  • c. 2.8 mA
  • d. 3.3 mA

12. If Rf = R1’, the voltage gain is _____.

clip_image009

  • a. 1
  • b. –1
  • c. 10
  • d. very small

13. Calculate the overall voltage gain of the circuit if R1 = 100 and Rf = 1 kΩ.

clip_image010

  • a. –1
  • b. –10
  • c. 11
  • d. 9

14. Calculate the overall voltage gain of the circuit if R1 = 100 Ω and Rf = 1 kΩ.

clip_image012

  • a. –1
  • b. –10
  • c. 11
  • d. 9

15. What is the voltage gain of the unity follower?

  • a. 0
  • b. 1
  • c. –1
  • d. Infinity

16. Calculate the input voltage if R1 = 100 Ω, Rf = 1 kΩ, and Vout = 550 mV.

clip_image013

  • a. –50 mV
  • b. –5 mV
  • c. 550 mV
  • d. 50 mV

17. Calculate the output voltage if R1 = R2 = R3 = 100 Ω, Rf = 1 kΩ, and V1 = V2 = V3 = 50 mV.

clip_image015

  • a. –1.5 V
  • b. 1.5 V
  • c. 0.5 V
  • d. –0.5 V

18. What is the scale multiplier (factor) of a basic integrator?

  • a. R / C
  • b. C / R
  • c. –RC
  • d. –1 / RC

19. The summing amplifier contains an inverting amplifier.

  • a. True
  • b. False

20. This circuit is referred to as a(n) _____.

clip_image017

  • a. inverting amplifier
  • b. noninverting amplifier
  • c. unity follower
  • d. integrator

21. This circuit is referred to as a(n) _____.

clip_image019

  • a. inverting amplifier
  • b. noninverting amplifier
  • c. differentiator
  • d. integrator

22. This circuit is referred to as a(n) _____.

clip_image020

  • a. inverting amplifier
  • b. noninverting amplifier
  • c. differentiator
  • d.integrator

23. Which of the following circuit conditions affect(s) the output offset voltage of an op-amp?

  • a. An input offset voltage, VIO
  • b. An input offset current, IIO
  • c. Both an input offset voltage, VIO and an input offset current, IIO
  • d. None of the above

24. What is the level of the roll-off in most op-amps?

  • a. –6 dB / decade
  • b. –20 dB / octave
  • c. –6 dB / decade or –20 dB / octave
  • d. –20 dB / decade or –6 dB / octave

25. Which of the following is (are) the result of gain reduction by a feedback?

  • a. The amplifier voltage gain is a more stable and precise value.
  • b. The input impedance of the circuit is increased over that of the op-amp alone.
  • c. The output impedance is reduced over that of the op-amp alone.
  • d. All of the above

26. What is the open-loop gain of an op-amp at the gain-bandwidth product of the op-amp?

  • a. 200,000
  • b. 50,000
  • c. 200
  • d. 1

27. What is the cutoff frequency of an op-amp if the unity-gain frequency is 1.5 MHz and the open-loop gain is 100,000?

  • a. 5 Hz
  • b. 10 Hz
  • c. 15 Hz
  • d. 20 Hz

28. What is the slew rate of an op-amp if the output voltages change from 2 V to 3 V in 0.2 ms?

  • a. 5 V/ms
  • b. 3 V/ms
  • c. 2 V/ms
  • d. 1 V/ms

29. For an op-amp having a slew rate SR = 5 V/ms, what is the maximum closed-loop voltage gain that can be used when the input signal varies by 0.2 V in 10 ms?

  • a. 150
  • b. 200
  • c. 250
  • d. 300

30. Calculate the output impedance of an inverting op-amp using the 741 op-amp (ro = 75 Ω, AOL = 200 V/mV) if R1 = 100 Ω and Rf = 1 kΩ.

  • a. 0.011
  • b. 0.00375
  • c. 0.0375
  • d. 0.375

31. What is the difference output voltage of any signals applied to the input terminals?

  • a. The differential gain times the difference input voltage.
  • b. The common-mode gain times the common input voltage.
  • c. The sum of the differential gain times the difference input voltage and the common-mode gain times the common input voltage.
  • d. The difference of the differential gain times the difference input voltage and the common-mode gain times the common input voltage.

32. What is the difference voltage if the inputs are an ideal opposite signal?

  • a. The differential gain times twice the input signal.
  • b. The differential gain times the input signal.
  • c. The common-mode gain times twice the input signal.
  • d. The common-mode gain times the input signal.

33. What is the difference voltage if the inputs are an ideal in-phase signal?

  • a. The differential gain times twice the input signal.
  • b. The differential gain times the input signal.
  • c. The common-mode gain times twice the input signal.
  • d. The common-mode gain times the input signal.

34. At what input voltage level does the output voltage level become numerically equal to the value of the differential gain of the amplifier?

  • a. Vi1 = –Vi2 = 0.25 V
  • b. V i1 = –V i2 = 0.50 V
  • c. V i1 = –V i2 = 0.75 V
  • d. V i1 = –Vi2 = 1.00 V

35. At what input voltage level does the output voltage level become numerically equal to the value of the common-mode gain of the amplifier?

  • a. Vi1 = –Vi2 = 0.25 V
  • b. Vi1 = –Vi2 = 0.50 V
  • c. Vi1 = –Vi2 = 0.75 V
  • d.Vi1 = –Vi2 = 1.00 V

FILL-IN-THE-BLANKS

1. An operational amplifier is a _____ gain and _____ bandwidth differential amplifier.

  • A. very low, narrow
  • B. low, wide
  • C. medium, narrow
  • D. very high, wide

2. An operational amplifier has a _____ input impedance and a _____ output impedance.

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

3. The output signal of an op-amp is _____ out of phase with its input signal connected to the inverting input terminal.

  • A. 0º
  • B. 90º
  • C. 180º
  • D. 270º

4. In double-ended (differential) input operation, _____.

  • A. an input is applied between the two input terminals
  • B. two separate signals are applied to the input terminals
  • C. either an input is applied between the two input terminals or two separate signals are applied to the input terminals
  • D. None of the above

5. An input applied to either input terminal will result in _____.

  • A. outputs from both output terminals, which have opposite polarities
  • B. outputs from both output terminals, which have the same polarities
  • C. a single output from one of the output terminals
  • D. None of the above

6. In a differential connection, the signals that are opposite at the inputs are _____ amplified, and those that are common to the two inputs are _____ amplified.

  • A. slightly, slightly
  • B. slightly, highly
  • C. highly, highly
  • D. highly, slightly

7. In a differential amplifier circuit, if an input signal is applied to either input with the other input connected to ground, the operation is referred to as _____.

  • A. double-ended
  • B. single-ended
  • C. common-mode
  • D. All of the above

8. If two opposite-polarity input signals are applied, the operation is referred to as _____.

  • A. double-ended
  • B. single-ended
  • C. common-mode
  • D. All of the above

9. If the same input is applied to both inputs, the operation is called _____.

  • A. double-ended
  • B. single-ended
  • C. common-mode
  • D. All of the above

10. The main feature of the differential amplifier is the _____ gain when opposite signals are applied to the inputs as compared to the _____ gain resulting from common inputs.

  • A. very large, large
  • B. very small, large
  • C. very small, very large
  • D. very large, very small

11. An IC unit containing a differential amplifier built using both bipolar and FET transistors is referred to as a _____ circuit.

  • A. CMOS
  • B. BiFET
  • C. BiMOS
  • D. None of the above

12. An IC unit containing a differential amplifier built using opposite-type MOSFET transistors is referred to as a _____ circuit.

  • A. CMOS
  • B. BiFET
  • C. BiMOS
  • D. None of the above

13. A _____ differential amplifier is particularly well suited for battery operation due to its low power consumption.

  • A. BiFET
  • B. BiMOS
  • C. CMOS
  • D. BJT

14. An ideal op-amp circuit has _____input impedance, _____ output impedance, and _____ voltage gain.

  • A. zero, infinite, infinite
  • B. infinite, zero, zero
  • C. zero, zero, infinite
  • D. infinite, zero, infinite

15. The _____ amplifier is the most widely used constant-gain amplifier circuit.

  • A. inverting
  • B. noninverting
  • C. differential
  • D. None of the above

16. The feedback component of an integrator is a(n) _____.

  • A. resistor
  • B. capacitor
  • C. inductor
  • D. diode

17. _____ is the unit for the slew rate, SR.

  • A. V/ms
  • B. ms/V
  • C. V
  • D. V/s

18. The maximum frequency at which an op-amp may operate depends on the _____.

  • A. bandwidth (BW)
  • B. slew rate (SR)
  • C. unity-gain bandwidth
  • D. All of the above

19. As the supply voltage increases, the voltage gain of the circuit _____ and the power consumption _____.

  • A. increases, increases
  • B. increases, decreases
  • C. decreases, decreases
  • D. decreases, increases

20. As the frequency increases, the input impedance of an op-amp _____ and the output impedance _____.

  • A. increases, increases
  • B. increases, decreases
  • C. decreases, decreases
  • D. decreases, increases

21. Inverting amplifier connection is more widely used because it has _____.

  • A. higher gain
  • B. better frequency stability
  • C. unit gain
  • D. None of the above

22. The output offset voltage is determined by _____.

  • A. the input offset voltage and input offset current
  • B. the closed-loop gain
  • C. both the input offset voltage and the closed-loop gain
  • D. None of the above

23. The ratio of the unity-gain frequency to the cutoff frequency is numerically equal to the level of _____.

  • A. CMRR
  • B. common-mode gain
  • C. closed-loop gain
  • D. open-loop gain

24. When both input signals are the same, a common signal element due to the two inputs can be defined as the _____ of the two signals.

  • A. difference
  • B. sum
  • C. average of the sum
  • D. product

25. The common-mode rejection ratio (CMRR) is defined by _____.

  • A. Ad / Ac
  • B. Ac / Ad
  • C. Ad × Ac
  • D. Ad + Ac

26. Ideally, the value of the CMRR is _____. Practically, the _____ the value of CMRR, the better the circuit operation.

  • A. zero, smaller
  • B. infinite, larger
  • C. zero, larger
  • D. infinite, smaller

Complete List of Chapter Quiz in Electronic Devices and Circuit Theory

Check your work.


Published by: Froyd Wess11:36

Wednesday, October 29, 2014

BJT and FET Frequency Response - MCQs Answers

Filed under:

Answers key for  BJT and FET Frequency Response
Below are the answers key for the Multiple Choice Questions (Quiz) in BJT and FET Frequency Response from the book Electronic Devices and Circuit Theory 10th Edition by Robert L. Boylestad.

1. 2.3

2. 2.3

3. 6

4. –13.01 dB

5. 316.228

6. 300 mW

7. 1.225 V

8. 1 mW

9. Low-frequency

10. All of the above

11. 0.50

12. 0.707

13. –3 dB

14. High

15. Low

16. High

17. 1.0

18. About 0º

19. 45º

20. 159.15 Hz

21. 63.43º

22. 2

23. 10

24. RE = 0 Ω

25. Highest

26. 238.73 Hz

27. All of the above

28. Mid

29. All of the above

30. All of the above

31. Common-base

32. clip_image010_thumb

33. 1 to 10 pF

34. 0.1 to 1 pF

35. It is composed only of odd harmonics.

FILL-IN-THE-BLANKS Questions

1. 10, e

2. less, negative

3. 10, 1

4. 600

5. sum

6. 50

7. All of the above

8. 0.707Av mid

9. increases, decreases, more

10. 6-dB

11. 20-dB

12. highest

13. mid-frequency

14. decreased

15. inverting

16. largest, smallest

17. decrease

18. lowest

19. common-base, common-emitter

20. lowest, maximum

21. significantly greater

22. –40 dB

23. decreases

24. fundamental

25. 0.33

Complete List of Chapter Quiz in Electronic Devices and Circuit Theory


Published by: Froyd Wess17:55