operational amplifiers

Question 1

An ideal operational amplifier has
infinite output impedance
zero input impedance
infinite bandwidth
All of the above

Answer 1

infinite bandwidth

Question 2

Another name for a unity gain amplifier is:
difference amplifier
comparator
single ended
voltage follower

Answer 2

voltage follower

Question 3

The open-loop voltage gain (Aol) of an op-amp is the
external voltage gain the device is capable of
internal voltage gain the device is capable of
most controlled parameter
same as Acl

Answer 3

internal voltage gain the device is capable of

Question 4

A series dissipative regulator is an example of a:
linear regulator
switching regulator
shunt regulator
dc-to-dc converter

Answer 4

linear regulator

Question 5

A noninverting closed-loop op-amp circuit generally has a gain factor:
less than one
greater than one
of zero
equal to one

Answer 5

greater than one

Question 6

In order for an output to swing above and below a zero reference, the op-amp circuit requires:
a resistive feedback network
zero offset
a wide bandwidth
a negative and positive supply

Answer 6

a negative and positive supply

Question 7

Op-amps used as high- and low-pass filter circuits employ which configuration?
noninverting
comparator
open-loop
inverting

Answer 7

inverting

Question 8

If ground is applied to the (+) terminal of an inverting op-amp, the (–) terminal will:
not need an input resistor
be virtual ground
have high reverse current
not invert the signal

Answer 8

be virtual groun

Question 9

An astable multivibrator is also known as a:
one-shot multivibrator
free-running multivibrator
bistable multivibrator
monostable multivibrator

Answer 9

free-running multivibrator

Question 10

With negative feedback, the returning signal:
aids the input signal
is proportional to output current
opposes the input signal
is proportional to differential voltage gain

Answer 10

opposes the input signal

Question 11

What starts a free-running multivibrator?
a trigger
an input signal
an external circuit
nothing

Answer 11

nothing

Question 12

A portion of the output that provides circuit stabilization is considered to be:
negative feedback
distortion
open-loop
positive feedback

Answer 12

negative feedback

Question 13

How many leads does the TO-5 metal can package of an operational amplifier have?
8, 10, or 12
6, 8, or 10
8 or 14
8 or 16

Answer 13

8, 10, or 12

Question 14

The closed-loop voltage gain of an inverting amplifier equals:
the ratio of the input resistance to the feedback resistance
the open-loop voltage gain
the feedback resistance divided by the input resistance
the input resistance

Answer 14

the feedback resistance divided by the input resistance

Question 15

All of the following are basic op-amp input modes of operation EXCEPT
inverting mode
common-mode
double-ended
single-ended

Answer 15

inverting mode

Question 16

A circuit whose output is proportional to the difference between the input signals is considered to be which type of amplifier?
common-mode
darlington
differential
operational

Answer 16

differential

Question 17

With negative feedback, the returning signal
is proportional to the output current
is proportional to the differential voltage gain
opposes the input signal
aids the input signal

Answer 17

opposes the input signal

Question 18

The voltage follower has a:
closed-loop voltage gain of unity
small open-loop voltage gain
closed-loop bandwidth of zero
large closed-loop output impedance

Answer 18

closed-loop voltage gain of unity

Question 19

The ratio between differential gain and common-mode gain is called:
amplitude
differential-mode rejection
common-mode rejection
phase

Answer 19

common-mode rejection

Question 20

In an open-loop op-amp circuit, whenever the inverting input (–) is negative relative to the noninverting input (+), the output will:
swing negative
close the loop
be balanced
swing positive

Answer 20

swing positive

Question 21

If the input to a comparator is a sine wave, the output is a:
ramp voltage
sine wave
rectangular wave
sawtooth wave

Answer 21

rectangulae wave

Question 22

What three subcircuits does a phase locked loop (PLL) consist of?
phase comparator, comparator, and VCO
phase comparator, bandpass filter, and VCO
phase comparator, bandpass filter, and demodulator
phase comparator, low-pass filter, and VCO

Answer 22

phase comparator, low-pass filter, and VCO

Question 23

The major difference between ground and virtual ground is that virtual ground is only a:
voltage reference
current reference
power reference
difference reference

Answer 23

voltage reference

Question 24

If an op-amp has one input grounded and the other input has a signal feed to it, then it is operating as what?
Common-mode
Single-ended
Double-ended
Noninverting mode

Answer 24

Single-ended

Question 25

The Schmitt trigger is a two-state device that is used for: pulse shaping peak detection input noise rejection filtering

Answer 25

pulse shaping

Question 26

The common-mode voltage gain is smaller than differential voltage gain equal to voltage gain greater than differential voltage gain None of the above

Answer 26

smaller than differential voltage gain

Question 27

How many logic states does an S-R flip-flop have? 2 3 4 5

Answer 27

4

Question 28

An output that is proportional to the addition of two or more inputs is from which type of amplifier? differentiator difference summing analog subtractor

Answer 28

summing

Question 29

In a PLL, to obtain lock, the signal frequency must: come within the lock range be less than the capture frequency come within the capture range be greater than the capture frequency

Answer 29

come within the capture range

Question 30

An ideal amplifier should have: high input current zero offset high output impedance moderate gain

Answer 30

zero offset

Question 31

The magnitude of closed-loop voltage gain (Acl) of an inverting amplifier equals: the ratio of the input resistance to the feedback resistance the open-loop voltage gain Aol the feedback resistance divided by the input resistance the input resistance

Answer 31

the feedback resistance divided by the input resistance

Question 32

What is the difference between common-mode and differential-mode input signals? phase relationship voltage current apparent power

Answer 32

phase relationship

Question 33

A circuit that uses an amplifier with passive filter elements is called a(n): relaxation oscillator signal generator differential amplifier active filter

Answer 33

active filter

Question 34

The input offset current equals the average of two base currents collector current divided by the current gain difference between two base-emitter voltages difference between two base currents

Answer 34

difference between two base currents

Question 35

The center frequency of a band-pass filter is always equal to the bandwidth –3 dB frequency bandwidth divided by Q geometric average of the critical frequencies

Answer 35

geometric average of the critical frequencies

Question 36

A zero-level detector is a comparator with a sine-wave output comparator with a trip point referenced to zero peak detector limiter

Answer 36

comparator with a trip point referenced to zero

Question 37

A digital-to-analog converter is an application of the scaling adder voltage-to-current converter noninverting amplifier adjustable bandwidth circuit

Answer 37

scaling adder

Question 38

If the value of resistor Rf in an 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 average of the individual inputs the inverted sum of the individual inputs the sum of the individual inputs the inverted average of the individual inputs

Answer 38

the inverted average of the individual inputs

Question 39

If the input to a comparator is a sine wave, the output is a ramp voltage sine wave rectangular wave sawtooth wave

Answer 39

rectangular wave

Question 40

A basic series regulator has an error detector a load a reference voltage both an error detector and a reference voltage

Answer 40

both an error detector and a reference voltage

Question 41

A comparator is an example of a(n) active filter current source linear circuit nonlinear circuit

Answer 41

nonlinear circuit

Question 42

Initially, the closed-loop gain (Acl) of a Wien-bridge oscillator should be Acl < 3 Acl > 3 0 Acl = 1

Answer 42

Acl > 3

Question 43

In an averaging amplifier, the input resistances are equal to the feedback resistance less than the feedback resistance greater than the feedback resistance unequal

Answer 43

greater than the feedback resistance

Question 44

A triangular-wave oscillator can consist of an op-amp comparator, followed by a(n) differentiator amplifier integrator multivibrator

Answer 44

integrator

Question 45

The ramp voltage at the output of an op-amp integrator increases or decreases at a linear rate increases or decreases exponentially is always increasing and never decreasing is constant

Answer 45

increases or decreases at a linear rate

Question 46

A two-pole high-pass active filter would have a roll-off rate of 40 dB/decade –40 dB/decade 20 dB/decade –20 dB/decade

Answer 46

–40 dB/decade

Question 47

When using an OTA in a Schmitt-trigger configuration, the trigger points are controlled by the Iout the IBIAS the Vout both Iout and IBIAS

Answer 47

both Iout and IBIAS

Question 48

The primary function of the oscillator in an isolation amplifier is to convert dc to high-frequency ac convert dc to low-frequency ac rectify high-frequency ac to dc produce dual-polarity dc voltages for the input to the demodulator

Answer 48

convert dc to high-frequency ac

Question 49

An instrumentation amplifier has a high output impedance power gain CMRR supply voltage

Answer 49

CMRR

Question 50

Circuits that shift the dc level of a signal are called limiters clampers peak detectors dc converters

Answer 50

clampers

Question 51

In the classic three-op-amp instrumentation amplifier, the differential voltage gain is usually produced by the first stage second stage mismatched resistors output op-amp

Answer 51

first stage