# Floyd: MCQ in Special-Purpose Op-Amp Circuits

(Last Updated On: December 8, 2019) This is the Multiple Choice Questions in Special-Purpose Op-Amp Circuits from the book Electronic Devices – Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

If you are looking for the Self-test in Floyd’s Electronic Devices proceed to

#### Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. A log amplifier may use the __________ junction of a BJT in the feedback loop.

A. base-collector

B. base-emitter

C. emitter-collector

D. emitter-ground

Solution:

2. An antilog amplifier has a _________ in series with the input.

A. BJT

B. diode

C. diode or BJT

D. resistor

Solution:

3. Instrumentation amplifiers are normally used to measure

A. small differential signal voltages.

B. signals superimposed on a common-mode voltage often much larger than the signal voltage.

C. both of the above

D. none of the above

Solution:

4. The main difference between the isolation amplifier and an instrumentation amplifier is

A. an instrumentation amplifier has an input stage.

B. an instrumentation amplifier has an output stage.

C. an instrumentation amplifier has a differential stage.

D. the input, output, and power supply stages of an isolation amplifier are all electrically isolated from each other.

Solution:

5. An OTA has

A. a bias-current input terminal.

B. high output impedance.

C. no fixed open-loop voltage gain.

D. all of the above

Solution:

6. Transconductance is the ratio of the output

A. current to the input voltage.

B. current to the input current.

C. voltage to the input voltage.

D. voltage to the input current.

Solution:

7. The log of a number is the

A. base to which the power must be raised to get that number.

B. power to which the base must be raised to get that number.

C. base of that number.

D. power of that number.

Solution:

8. What part of the characteristic curve of a diode is useful for log amplifiers?

A. the log region above 0.7 V

B. the log region below 0.7 V

C. the log region between 0 V and 0.7 V

D. the log region below the zener voltage

Solution:

9. In logarithmic signal compression,

A. large and small voltages are compressed equally.

B. large voltages are compressed more than small voltages.

C. large voltages are compressed less than smaller voltages.

D. none of the above

Solution:

10. A constant-current source delivers a load current that

A. remains constant when the load resistance changes.

C. varies inversely with load resistance.

D. varies inversely with input voltage.

Solution:

11. A current-to-voltage converter produces a

A constant output voltage for a variable input current.

B. variable output voltage for a constant input current.

C. proportional output voltage for a variable input current.

D. proportional output current for a variable input voltage.

Solution:

12. Refer to Figure 14-1(a). This circuit is a setup for Figure 14-1

A. an antilog amplifier.

B. a constant-current source.

C. an instrumentation amplifier.

D. an isolation amplifier.

Solution:

13. Refer to Figure 14-1(b). This circuit is a setup for

A. an antilog amplifier.

B. a constant-current source.

C. an instrumentation amplifier.

D. an isolation amplifier.

Solution:

14. Refer to Figure 14-1(c). This circuit is a setup for

A. an antilog amplifier.

B. a constant-current source.

C. an instrumentation amplifier.

D. an isolation amplifier.

Solution:

15. Refer to Figure 14-1(d). This circuit is a setup for

A. an antilog amplifier.

B. a constant-current source.

C. an instrumentation amplifier.

D. an isolation amplifier.

Solution:

16. The OTA has a _____ input impedance and a _____ CMRR.

A. high, low

B. low, high

C. high, high

D. low, low

Solution:

17. Refer to Figure 14-2. Which circuit is known as a voltage-to-current converter? Figure 14-2

A. a

B. b

C. c

D. d

Solution:

18. Refer to Figure 14-2. Which circuit is known as a current-to-voltage converter?

A. a

B. b

C. c

D. d

Solution:

19. Refer to Figure 14-2. Which circuit is known as an OTA?

A. a

B. b

C. c

D. d

Solution:

20. Refer to Figure 14-2. Which circuit is known as a peak detector?

A. a

B. b

C. c

D. d

Solution:

21. A(n) _____ amplifier is a differential voltage-gain device that amplifies the difference between the voltages existing at its two input terminals.

A. instrumentation

B. isolation

C. operational transconductance

D. log

Solution:

22. The main purpose of an instrumentation amplifier is to amplify _____ signals that are riding on _____ common-mode voltages.

A. small, small

B. small, large

C. large, small

D. large, large

Solution:

23. What is a key characteristic of an instrumentation amplifier?

A. high CMRR

B. high output offset

C. high output impedance

D. none of the above

Solution:

24. A basic _____ amplifier is formed by three op-amps and seven resistors.

A. instrumentation

B. isolation

C. log

D. antilog

Solution:

25. The voltage gain of a basic instrumentation amplifier is set by a(n)

A. diode.

B. capacitor.

C. resistor.

D. inductor.

Solution:

26. A(n) _____ amplifier provides “a barrier” between the input and output for the protection of human life or sensitive equipment.

A. instrumentation

B. isolation

C. operational transconductance

D. voltage-to-current

Solution:

27. What is (are) the principal area(s) of application for isolation amplifiers?

A. medical

B. power plant

C. automation

D. all of the above

Solution:

28. The operational transconductance amplifier (OTA) is primarily a _____ -to- _____ amplifier.

A. current, voltage

B. voltage, current

C. current, resistance

D. resistance, current

Solution:

29. A log amplifier has _____ in the feedback loop.

A. a diode

B. a BJT

C. a resistor

D. either a diode or a BJT

Solution:

30. The process known as signal compression is used with a(n) ____ amplifier.

A. log

B. antilog

C. instrumentation

D. isolation

Solution:

#### TRUE/FALSE

1. One of the key characteristics of an instrumentation amplifier is high input impedance.

A. True

B. False

Solution:

2. To construct an instrumentation amplifier, two op-amps and seven resistors are needed.

A. True

B. False

Solution:

3. An isolation amplifier provides ac isolation between input and output.

A. True

B. False

Solution:

4. One of the principal areas of application for an isolation amplifier is power plant instrumentation.

A. True

B. False

Solution:

5. The main purpose of an instrumentation amplifier is to amplify small signals riding on large common-mode voltages.

A. True

B. False

Solution:

6. Instrumentation amplifiers are commonly used in environments with high common-mode noise.

A. True

B. False

Solution:

7. In an isolation amplifier, the third op-amp is used as a unity-gain differential amplifier.

A. True

B. False

Solution:

8. An OTA is primarily a current-to-voltage amplifier.

A. True

B. False

Solution:

9. OTA stands for operational transistor amplifier.

A. True

B. False

Solution:

10. A constant-current source delivers a load current that remains constant only when the load resistance remains constant.

A. True

B. False

Solution:

© 2014 PinoyBIX Engineering. © 2019 All Rights Reserved | How to Donate? |   