# Boylestad: MCQ in Operational Amplifiers

(Last Updated On: December 2, 2019) This is the Multiple Choice Questions 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. 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.

#### Online Questions and Answers Topic Outline

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

#### Practice Exam Test Questions

Choose the letter of the best answer in each questions.

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

a. Oscillators

b. Filters

c. Instrumentation circuits

d. All of the above

Solution:

2. This circuit is an example of a _________. a. single-ended input

b. double-ended (differential) input

c. double-ended output

d. common-mode operation

Solution:

3. This circuit is an example of a ________. a. single-ended input

b. double-ended (differential) input

c. double-ended output

d. common-mode operation

Solution:

4. This circuit is an example of a ________. a. single-ended input

b. double-ended (differential) input

c. double-ended output

d. common-mode operation

Solution:

5. This circuit is an example of a _________. a. single-ended input

b. double-ended (differential) input

c. double-ended output

d. common-mode operation

Solution:

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

Solution:

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

Solution:

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

Solution:

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

d. TTL, BiFET, BiMOS

Solution:

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

Solution:

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

Solution:

12. If Rf = R1’, the voltage gain is ________. a. 1

b. –1

c. 10

d. very small

Solution:

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

b. –10

c. 11

d. 9

Solution:

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

b. –10

c. 11

d. 9

Solution:

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

a. 0

b. 1

c. –1

d. Infinity

Solution:

16. Calculate the input voltage if R1 = 100 Ω, Rf = 1 kΩ, and Vout = 550 mV. a. –50 mV

b. –5 mV

c. 550 mV

d. 50 mV

Solution:

17. Calculate the output voltage if R1 = R2 = R3 = 100 Ω, Rf = 1 kΩ, and V1 = V2 = V3 = 50 mV. a. –1.5 V

b. 1.5 V

c. 0.5 V

d. –0.5 V

Solution:

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

a. R/C

b. C/R

c. –RC

d. –1/RC

Solution:

19. The summing amplifier contains an inverting amplifier.

a. True

b. False

Solution:

20. This circuit is referred to as a(n) ________. a. inverting amplifier

b. noninverting amplifier

c. unity follower

d. integrator

Solution:

21. This circuit is referred to as a(n) ________. a. inverting amplifier

b. noninverting amplifier

c. differentiator

d. integrator

Solution:

22. This circuit is referred to as a(n) ________. a. inverting amplifier

b. noninverting amplifier

c. differentiator

d.integrator

Solution:

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

Solution:

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

b. –20 dB/octave

c. –6 dB/decade or –20 dB/octave

d. –20 dB/decade or –6 dB/octave

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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.

Solution:

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.

Solution:

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.

Solution:

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. Vi1 = –Vi2 = 0.50 V

c. Vi1 = –Vi2 = 0.75 V

d. Vi1 = –Vi2 = 1.00 V

Solution:

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

Solution:

#### 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

Solution:

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

A. high, low

B. high, high

C. low, low

D. low, high

Solution:

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

A. 0°

B. 90°

C. 180°

D. 270°

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

A. inverting

B. noninverting

C. differential

D. None of the above

Solution:

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

A. resistor

B. capacitor

C. inductor

D. diode

Solution:

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

A. V/ms

B. ms/V

C. V

D. V/s

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

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

Solution:

### Complete List of Chapter Quiz in Electronic Devices and Circuit Theory

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