1475 + Mcqs in Electronic Devices Page 25 McqOptions

1201.	To reduce the effects of noise resulting in erratic switching of output states of a comparator, you can use
A.	the upper trigger point.
B.	the lower trigger point.
C.	nonzero-level detection.
D.	hysteresis.
Answer» E.

Discussion

1202.	Refer to the given figure. Determine the output voltage, VOUT.
A.	1.05 V
B.	0.35 V
C.	0.35 V
D.	1.05 V
Answer» B. 0.35 V

Discussion

1203.	What is (are) the necessary component(s) for the design of a bounded comparator?
A.	rectifier diodes
B.	zener diodes
C.	both of the above
Answer» C. both of the above

Discussion

1204.	In a flash A/D converter, the priority encoder is used to
A.	select the first input.
B.	select the highest value input.
C.	select the lowest value input.
D.	select the last input.
Answer» C. select the lowest value input.

Discussion

1205.	What circuit produces an output that approximates the area under the curve of an input function?
A.	integrator
B.	differentiator
C.	summing amplifier
D.	comparator
Answer» B. differentiator

Discussion

1206.	If an op-amp comparator has a gain of 100,000, an input difference of 0.2 mV above reference, and a supply of 12 V, the output will be
A.	20 V.
B.	12 V.
C.	10 V.
D.	15 V.
Answer» C. 10 V.

Discussion

1207.	A comparator with a Schmitt trigger has
A.	two trigger levels.
B.	a fast response.
C.	a slow response.
D.	one trigger level.
Answer» B. a fast response.

Discussion

1208.	In a(n) ________, when the input voltage exceeds a specified reference voltage, the output changes state.
A.	integrator
B.	differentiator
C.	summing amplifier
D.	comparator
Answer» E.

Discussion

1209.	The parallel-resonant impedance of a crystal oscillator is ________.
A.	very low
B.	low
C.	medium
D.	very high
Answer» E.

Discussion

1210.	In a Nyquist plot, as the frequency increases, the phase shift between input and output signals ________.
A.	remains the same
B.	decreases
C.	increases
D.	None of the above
Answer» D. None of the above

Discussion

1211.	Operational amplifiers are never used as nonlinear devices.
A.	True
B.	False
Answer» C.

Discussion

1212.	In an op-amp comparator, when the input voltage exceeds a reference voltage, the voltage output changes state.
A.	True
B.	False
Answer» B. False

Discussion

1213.	Refer to the given figure. What is the output voltage?
A.	0.5 V
B.	0.5 V
C.	2 V
D.	2 V
Answer» C. 2 V

Discussion

1214.	What type(s) of circuit(s) use comparators?
A.	summer
B.	nonzero-level detector
C.	averaging amplifier
D.	summer and nonzero-level detector
Answer» C. averaging amplifier

Discussion

1215.	A good example of hysteresis is a(n)
A.	AM radio.
B.	thermostat.
C.	alarm clock.
D.	none of the above
Answer» C. alarm clock.

Discussion

1216.	Series-feedback connections tend to ________ the input resistance. Shunt feedback connections tend to ________ the input resistance.
A.	decrease, increase
B.	increase, decrease
C.	increase, increase
D.	decrease, decrease
Answer» C. increase, increase

Discussion

1217.	In practice, A is made ________ and the system is started oscillating by amplifying noise voltage, which is always present.
A.	greater than 1
B.	smaller than 1
C.	equal to 1
D.	None of the above
Answer» B. smaller than 1

Discussion

1218.	Voltage feedback connections tend to ________ the output impedance. Current feedback connections tend to ________ the output impedance.
A.	decrease, increase
B.	increase, decrease
C.	increase, increase
D.	decrease, decrease
Answer» B. increase, decrease

Discussion

1219.	In the phase-shift oscillator, the operating frequency is determined by ________.
A.	resistance only
B.	capacitance only
C.	LC combinations
D.	RC combinations
Answer» E.

Discussion

1220.	In the Barkhausen criterion, the loop gain A is equal to ________.
A.	<img src="/_files/images/electronic-devices-and-circuit-theory/infinity.gif">
B.	200,000
C.	0
D.	1
Answer» E.

Discussion

1221.	An op-amp integrator uses a capacitor as the feedback element.
A.	True
B.	False
Answer» B. False

Discussion

1222.	An op-amp can be used as a comparator to determine when an input voltage exceeds a certain level.
A.	True
B.	False
Answer» B. False

Discussion

1223.	The output voltage of a summing amplifier is proportional to the sum of the input voltages.
A.	True
B.	False
Answer» B. False

Discussion

1224.	Line regulation is the percentage change in output voltage for a given change in input line current.
A.	True
B.	False
Answer» C.

Discussion

1225.	At the series-resonant frequency, the amount of positive feedback is ________.
A.	very large
B.	large
C.	small
D.	very small
Answer» B. large

Discussion

1226.	In the phase-shift oscillator, the gain of the amplifier stage must be ________.
A.	0
B.	less than 29
C.	greater than 29
D.	<img src="/_files/images/electronic-devices-and-circuit-theory/infinity.gif">
Answer» D. <img src="/_files/images/electronic-devices-and-circuit-theory/infinity.gif">

Discussion

1227.	The series-resonant impedance of a crystal oscillator is ________.
A.	very low
B.	low
C.	medium
D.	very high
Answer» B. low

Discussion

1228.	Negative feedback results in ________.
A.	decreased voltage gain
B.	increased voltage gain
C.	oscillation in the circuit
D.	None of the above
Answer» B. increased voltage gain

Discussion

1229.	What is the gain at the origin of the Nyquist plot?
A.	Zero
B.	A negative value
C.	A positive value
D.	Undefined
Answer» B. A negative value

Discussion

1230.	Positive feedback results in ________.
A.	decreased voltage gain
B.	increased voltage gain
C.	oscillation in the circuit
D.	None of the above
Answer» D. None of the above

Discussion

1231.	The series 7900 ICs are ________.
A.	positive voltage regulators
B.	negative voltage regulators
C.	both positive and negative voltage regulators
D.	adjustable-set voltage regulators
Answer» C. both positive and negative voltage regulators

Discussion

1232.	A complete power supply has a ________.
A.	rectifier
B.	filter
C.	voltage regulator
D.	All of the above
Answer» E.

Discussion

1233.	If the value of the full-load voltage is the same as the no-load voltage, the voltage regulation calculated is ________.
A.	0%
B.	a negative percentage
C.	a positive percentage
D.	None of the above
Answer» B. a negative percentage

Discussion

1234.	The ________ the voltage regulation, the ________ the operation of the voltage supply circuit.
A.	smaller, better
B.	larger, better
C.	smaller, worse
D.	None of the above
Answer» B. larger, better

Discussion

1235.	In a half-wave rectifier, the dc voltage level is ________ the ripple voltage level.
A.	smaller than
B.	the same as
C.	larger than
D.	None of the above
Answer» B. the same as

Discussion

1236.	The ________ the diode conduction time, the ________ the amount of the charging current through the capacitor filter.
A.	shorter, larger
B.	shorter, smaller
C.	longer, larger
D.	None of the above
Answer» B. shorter, smaller

Discussion

1237.	A basic voltage regulator consists largely of a reference source, an error detector, and a control device.
A.	True
B.	False
Answer» B. False

Discussion

1238.	Switching regulators are not very efficient.
A.	True
B.	False
Answer» C.

Discussion

1239.	The input resistance at the base of a transistor is RIN DCIBRE.
A.	True
B.	False
Answer» C.

Discussion

1240.	The charging and discharging of the capacitor filter take ________ of the period of the input voltage.
A.	0.25
B.	0.5
C.	0.75
D.	1
Answer» C. 0.75

Discussion

1241.	The frequency of the output voltage of a full-wave rectifier is ________ the frequency of its input voltage.
A.	the same as
B.	twice
C.	one-half
D.	one-third
Answer» C. one-half

Discussion

1242.	________ is a frequency-determining component in a unijunction oscillator.
A.	Total resistance
B.	Total capacitance
C.	Intrinsic stand-off ratio
D.	All of the above
Answer» E.

Discussion

1243.	A Schmitt trigger is
A.	a comparator with only one trigger point.
B.	a comparator with hysteresis.
C.	a comparator with three trigger points.
D.	none of the above.
Answer» C. a comparator with three trigger points.

Discussion

1244.	Refer to the given figure. This circuit is known as
A.	a noninverting amplifier.
B.	a differentiator.
C.	an integrator.
D.	a summing amplifier.
Answer» D. a summing amplifier.

Discussion

1245.	The output of a Schmitt trigger is a
A.	pulse waveform.
B.	sawtooth waveform.
C.	sinusoidal waveform.
D.	triangle waveform.
Answer» B. sawtooth waveform.

Discussion

1246.	A pnp transistor requires the same bias polarities as the npn transistor.
A.	True
B.	False
Answer» C.

Discussion

1247.	The purpose of biasing is to establish a proper Q-point.
A.	True
B.	False
Answer» B. False

Discussion

1248.	The base bias circuit is not beta-dependent.
A.	True
B.	False
Answer» C.

Discussion

1249.	In the Colpitts oscillator, the elements X1 and X2 are ________ and X3 is a(n) ________.
A.	inductors, capacitor
B.	capacitors, inductor
C.	capacitors, resistor
D.	inductors, resistor
Answer» C. capacitors, resistor

Discussion

1250.	In a Hartley oscillator, the elements X1 and X2 are ________ and X3 is a(n) ________.
A.	inductors, capacitor
B.	capacitors, inductor
C.	capacitors, resistor
D.	inductors, resistor
Answer» B. capacitors, inductor

Discussion

Explore topic-wise MCQs in Engineering.

To reduce the effects of noise resulting in erratic switching of output states of a comparator, you can use

Refer to the given figure. Determine the output voltage, VOUT.

What is (are) the necessary component(s) for the design of a bounded comparator?

In a flash A/D converter, the priority encoder is used to

What circuit produces an output that approximates the area under the curve of an input function?

If an op-amp comparator has a gain of 100,000, an input difference of 0.2 mV above reference, and a supply of 12 V, the output will be

A comparator with a Schmitt trigger has

In a(n) ________, when the input voltage exceeds a specified reference voltage, the output changes state.

The parallel-resonant impedance of a crystal oscillator is ________.

In a Nyquist plot, as the frequency increases, the phase shift between input and output signals ________.

Operational amplifiers are never used as nonlinear devices.

In an op-amp comparator, when the input voltage exceeds a reference voltage, the voltage output changes state.

Refer to the given figure. What is the output voltage?

What type(s) of circuit(s) use comparators?

A good example of hysteresis is a(n)

Series-feedback connections tend to ________ the input resistance. Shunt feedback connections tend to ________ the input resistance.

In practice, A is made ________ and the system is started oscillating by amplifying noise voltage, which is always present.

Voltage feedback connections tend to ________ the output impedance. Current feedback connections tend to ________ the output impedance.

In the phase-shift oscillator, the operating frequency is determined by ________.

In the Barkhausen criterion, the loop gain A is equal to ________.

An op-amp integrator uses a capacitor as the feedback element.

An op-amp can be used as a comparator to determine when an input voltage exceeds a certain level.

The output voltage of a summing amplifier is proportional to the sum of the input voltages.

Line regulation is the percentage change in output voltage for a given change in input line current.

At the series-resonant frequency, the amount of positive feedback is ________.

In the phase-shift oscillator, the gain of the amplifier stage must be ________.

The series-resonant impedance of a crystal oscillator is ________.

Negative feedback results in ________.

What is the gain at the origin of the Nyquist plot?

Positive feedback results in ________.

The series 7900 ICs are ________.

A complete power supply has a ________.

If the value of the full-load voltage is the same as the no-load voltage, the voltage regulation calculated is ________.

The ________ the voltage regulation, the ________ the operation of the voltage supply circuit.

In a half-wave rectifier, the dc voltage level is ________ the ripple voltage level.

The ________ the diode conduction time, the ________ the amount of the charging current through the capacitor filter.

A basic voltage regulator consists largely of a reference source, an error detector, and a control device.

Switching regulators are not very efficient.

The input resistance at the base of a transistor is RIN DCIBRE.

The charging and discharging of the capacitor filter take ________ of the period of the input voltage.

The frequency of the output voltage of a full-wave rectifier is ________ the frequency of its input voltage.

________ is a frequency-determining component in a unijunction oscillator.

A Schmitt trigger is

Refer to the given figure. This circuit is known as

The output of a Schmitt trigger is a

A pnp transistor requires the same bias polarities as the npn transistor.

The purpose of biasing is to establish a proper Q-point.

The base bias circuit is not beta-dependent.

In the Colpitts oscillator, the elements X1 and X2 are ________ and X3 is a(n) ________.

In a Hartley oscillator, the elements X1 and X2 are ________ and X3 is a(n) ________.

Series-feedback connections tend to the input resistance. Shunt feedback connections tend to the input resistance.

Voltage feedback connections tend to the output impedance. Current feedback connections tend to the output impedance.

The the voltage regulation, the the operation of the voltage supply circuit.

The the diode conduction time, the the amount of the charging current through the capacitor filter.

In the Colpitts oscillator, the elements X1 and X2 are and X3 is a(n) .

In a Hartley oscillator, the elements X1 and X2 are and X3 is a(n) .