Deck 13: Basic Op-Amp Circuits

Question 1

The output of an op- amp differentiator with a rectangular input is a

A)series of positive and negative spikes.
B)ramp voltage.
C)sine wave.

Answer 1

A

Question 2

An integrator circuit

A)produces a ramp voltage at its output for a step input voltage.
B)uses a capacitor in its feedback circuit.
C)uses an inductor in its feedback circuit.
D)A and B above.

Answer 2

D

Question 3

A window comparator

A)detects an input voltage between two limits.
B)clamps the input positively.
C)has only one usable threshold.
D)uses hysteresis to speed up response.

Answer 3

A

Question 4

Refer to b)in the figure above. A square wave input is applied to this circuit. The output voltage is most likely to be

A)a square wave.
B)a sine wave.
C)a triangle wave.
D)no output.

Question 5

An op- amp has an open- loop gain of 100,000. Vsat = +/- 12 V. A differential signal voltage of 150 µVp- p is applied between the inputs. The output voltage is

A)24 Vp- p.
B)12 Vp- p.
C)12 V.
D)- 12 V.

Question 6

A mathematical operation for finding the area under the curve of a graph is called

A)curve averaging.
B)integration.
C)differentiation.
D)linear regression.

Question 7

A summing amplifier can add

A)dc to ac voltages.
B)dc voltages.
C)ac voltages.
D)All of the above.

Question 8

A two- input summing amplifier has input voltages of 3 V and 4 V. If Rf is open, the output voltage will be approximately

A)- Vsat.
B)+7 V.
C)- 7 V.
D)+Vsat.

Question 9

Refer to b)in the figure above. This type of circuit will usually have

A)a triangle wave output.
B)a square wave output if the input is a sine wave.
C)a ramp output for a square wave input.
D)None of the above.

Question 10

A differentiator circuit

A)produces a square wave at its output for a triangle wave input.
B)uses a capacitor in its feedback circuit.
C)uses a resistor in its feedback circuit.
D)A and C above.

Question 11

A Schmitt trigger is a comparator with

A)hysteresis.
B)one trigger point.
C)two trigger points.
D)A and C above.

Question 12

The circuit overcomes the problem of false switching caused by noise on the inputs).

A)Schmitt trigger
B)input noise eliminator
C)input buffer
D)differentiator

Question 13

Each of the following is used to establish a reference voltage on a comparator input except a

A)voltage divider.
B)LED.
C)zener diode.
D)battery.

Question 14

Refer to a)in the figure above. If a solder splash shorted the two ends of the feedback resistor to each other, the output voltage would be

A)- Vsat.
B)0.5 V.
C)0 V.
D)- 0.5 V.

Question 15

A D/A converter is an application of the

A)noninverting amplifier.
B)scaling adder.
C)adjustable bandwidth circuit.
D)voltage- to- current converter.

Question 16

An op- amp has an open- loop gain of 90,000. Vsat = +/- 13 V. A differential voltage of 0.1 Vp- p is applied between the inputs. The output voltage is

A)26 Vp- p.
B)13 V.
C)- 13 V.
D)13 Vp- p.

Question 17

A mathematical operation that determines the rate of change of a curve is called

A)integration.
B)differentiation.
C)linear regression.
D)curve averaging.

Question 18

A Schmitt trigger has

A)only negative feedback.
B)only one trip point.
C)a triangular output.
D)two slightly different trip points.

Question 19

An R/2R ladder circuit would be found in a

A)common emitter amplifier.
B)differential amplifier.
C)D/A converter circuit.
D)Schmitt trigger circuit.

Question 20

Refer to c)in the figure above. With the inputs shown, the output voltage would be

A)+Vsat.
B)- 7 V.
C)- Vsat.
D)7 V.

Question 21

The output of a Schmitt trigger is a

A)triangle wave.
B)sine wave.
C)square wave.
D)sawtooth.

Question 22

A Schmitt trigger is a comparator with

A)negative feedback.
B)positive feedback.
C)Neither A nor B.
D)Both A and B.

Question 23

A bounded comparator uses in the feedback circuit.

A)zener diodes
B)an inductor
C)a resonant filter
D)equal- valued resistors

Question 24

Output bounding is the process of the output voltage range of a comparator.

A)comparing
B)limiting
C)filtering
D)extending

Question 25

See a)in the figure above. This circuit is known as

A)a differentiator.
B)an integrator.
C)a noninverting amplifier.
D)a summing amplifier.

Question 26

If the input to a comparator is a sine wave, the output is a

A)sine wave.
B)ramp voltage.
C)rectangular wave.
D)sawtooth wave.

Question 27

Refer to b)in the figure above. The output voltage with the inputs as shown is

A)26 Vp- p.
B)+Vsat.
C)17.06 Vp- p.
D)- Vsat.

Question 28

In an op- amp integrator, the current through the input resistor is into the

A)inverting input.
B)bypass capacitor.
C)feedback capacitor.
D)noninverting input.

Question 29

Refer to a)in the figure above. If VCC = 15 V, the approximate output voltage is

A)- 13 V.
B)- 1 V.
C)13 V.
D)1 V.

Question 30

Hysteresis voltage is defined as

A)the voltage of the lower trigger point.
B)the sum of voltages of the upper and the lower trigger points.
C)the voltage of the upper trigger point.
D)the difference in voltage between the upper and the lower trigger points.

Question 31

Refer to the figure above. Which of these circuits is known as an integrator?

A)b)
B)a)
C)Neither of the above.

Question 32

A comparator is an example of an)

A)current source.
B)linear circuit.
C)active filter.
D)nonlinear circuit.

Question 33

The input makes the summing amplifier circuit possible.

A)virtual ground at the noninverting
B)low voltage
C)high voltage
D)virtual ground at the inverting

Question 34

A zero crossing detector is a

A)comparator with a trip point referenced to zero.
B)peak detector.
C)limiter.
D)comparator with no output.

Question 35

If the value of resistor Rf in a averaging amplifier circuit is equal to the value of one input resistor divided by the number of inputs, the output will be equal to the

A)average of the individual inputs.
B)sum of the individual inputs.
C)inverted sum of the individual inputs.
D)inverted average of the individual inputs.