Deck 16: Additional Op-Amp Applications

Question 1

A summing amplifier may be used as a/an

A) linear amplifier.
B) oscillator.
C) digital-to-analog converter.
D) analog-to-digital converter.

Answer 1

digital-to-analog converter.

Question 2

Which of the following can best be described as a high-gain, high CMRR circuit that is used to detect and amplify low-level signals?

A) An op-amp audio amplifier
B) A high-z voltmeter
C) An instrumentation amplifier
D) A subtractor

Answer 2

An instrumentation amplifier

Question 3

The output from a differentiator is proportional to

A) the peak value of the input voltage.
B) the rate of change of the input voltage.
C) the rate of change of the input frequency.
D) None of these are correct.

Answer 3

the rate of change of the input voltage.

Question 4

The differentiator can be used to convert a

A) square wave into a triangular wave.
B) square wave into a sine wave.
C) triangular wave into a sine wave.
D) triangular wave into a square wave.

Question 5

The ideal output from an op-amp integrator with a square wave input would be a triangular waveform. What is the actual output wave shape?

A) Sinusoidal
B) Exponential
C) Triangular
D) Square

Question 6

Which of the following can best be described as a high-gain, minimum distortion, high input impedance, low output impedance circuit operated between 20 Hz and 20 kHz?

A) An op-amp audio amplifier
B) A high-z voltmeter
C) An instrumentation amplifier
D) A subtractor

Question 7

The gain of a typical comparator is approximately equal to

A) unity 1).
B) 3 dB.
C) the open-loop voltage gain AOL) of its op-amp.
D) 0 dB.

Question 8

A summing amplifier provides an output that is always

A) equal to the difference between its input voltages.
B) equal to the sum of its input voltages.
C) equal or proportional to the sum of its input voltages.
D) None of these are correct.

Question 9

The input voltages to the circuit in Figure are as follows: V1 = 2 V, V2 = 4 V, and V3 = 8 V. What is the output voltage from the circuit?

A) +11 V
B) +6 V
C) -11 V
D) -6 V

Question 10

The comparator may be used as a/an

A) linear amplifier.
B) oscillator.
C) sine wave to rectangular wave converter.
D) rectangular wave to triangular wave converter.

Question 11

The circuit in Figure has the following values: R1 = 7 kΩ, R2 = 1 kΩ, CB = 1 μF, and supply voltages of ±10 V. What is the value of Vref for this circuit?

A) +1.25 V
B) -1.25 V
C) + 2.5 V
D) -7.5 V

Question 12

A comparator is a circuit that is used to provide a output when the input voltage is more than a fixed reference voltage.

A) positive; positive; positive
B) positive; negative; positive
C) negative; positive; negative
D) All of these are correct.

Question 13

What is the general-class equation for the circuit in Figure?

A) Vout = V1 + 2V2 + 4V3
B) -Vout = V1 + 0.5V2 + 0.25V3
C) -Vout = V1 + 2V2 + 0.25V3
D) None of these are correct.

Question 14

Two common-mode inputs to an instrumentation amplifier have identical .

A) amplitude
B) amplitude and phase
C) frequency
D) amplitude and frequency

Question 15

Instrumentation amplifiers are used to amplify signals.

A) high frequency
B) out of phase
C) high level
D) low level

Question 16

The key to obtaining a triangular output from an integrator with a square wave input is to provide

A) a constant-current charging source for the capacitor.
B) a constant-frequency charging source for the capacitor.
C) a constant-voltage charging source for the capacitor.
D) a short RC time constant.

Question 17

The ideal output from an RC integrator would be a triangular waveform when the input signal is a square wave. What is the actual output wave shape?

A) Sinusoidal
B) Exponential
C) Triangular
D) Square

Question 18

A comparator has the following values: RL = 20 kΩ, VS = +10 V, and Vref = +2 V applied to the inverting input). If the noninverting input goes to +3 V, the output voltage

A) will be approximately +9 V.
B) will be approximately -9 V.
C) will be approximately +3 V.
D) cannot be determined without knowing the value of ACL for the circuit.

Question 19

A summing amplifier has the following values: Rf = 10 kΩ, and R1=R2=R3=R4=40 kΩ. Which of the following statements is true about the circuits?

A) The circuit will not work with the values given.
B) The output will equal the average of the four input voltages.
C) The output will equal the sum of the four input voltages.
D) The output will equal the sum of the squares of the four input voltages.

Question 20

The use of a variable comparator allows for

A) changing the values of VS.
B) processing ultra-high frequency signals.
C) changing the value of Vref.
D) changing the limits of Vout.

Question 21

The circuit in Figure has the following values: R1 = 7 kΩ, R2 = 1 kΩ, CB = 1 μF, and supply voltages of ±10 V. The input is + 1 V. What is the approximate output voltage?

A) + 9 V
B) - 9 V
C) + 5 V
D) - 5 V

Question 22

Circuit A is an) .

A) linear amplifier
B) integrator
C) differentiator
D) comparator

Question 23

The circuit in Figure has the following values: R1=10 kΩ, Rf = 180 kΩ, and C1 = 0.1 μF. Which of the following statements is true?

A) The maximum voltage gain of the circuit equals the ratio of Rf to R1.
B) The maximum voltage gain of the circuit is approximately equal to the AOL rating of the op-amp.
C) The circuit is an inverting amplifier with a bypassed feedback resistor.
D) None of the above statements are true.

Question 24

Circuit B is an) .

A) linear amplifier
B) integrator
C) differentiator
D) comparator

Question 25

The circuit in Figure has the following values: R1=10 kΩ and C1 = 0.1 μF. Which of the following statements is true?

A) The maximum voltage gain of the circuit equals the ratio of Rf to R1.
B) The maximum voltage gain of the circuit is approximately equal to the AOL rating of the op-amp.
C) The circuit is an inverting amplifier with an input coupling capacitor.
D) None of the above statements are true.

Question 26

The circuit in Figure is an) .

A) differentiator
B) comparator
C) instrumentation amplifier
D) ramp generator

Question 27

CB is used to

A) filter out power supply current surges.
B) prevent variations in vin from affecting the voltage divider.
C) filter out unwanted stray inductance.
D) filter out unwanted stray capacitance.