Deck 18: Passive Filters

Question 1

What is the voltage gain of the amplifier in Figure 18-1(a)?

A)1000
B)1
C)100,000
D)10

Answer 1

1

Question 2

A voltage-follower op-amp has a voltage gain greater than one.

Answer 2

False

Question 3

The ideal amplifier has infinite gain, infinite input impedance, and zero output impedance.

Answer 3

True

Question 4

If , the voltage gain equals ________.

A)-38.3
B)-1
C)-39.3
D)infinite

Question 5

If , the voltage gain equals ________.

A)6
B)5
C)50
D)51

Question 6

A typical value of input bias current for an op-amp is around 80 nA.

Question 7

Differential amplifiers provide high voltage gain and low common-mode rejection.

Question 8

An op-amp with a low CMRR easily rejects noise signals that appear at both inputs.

Question 9

Identify the open-loop amplifier in Figure 18-1.

A)Figure 18-1(a)
B)Figure 18-1(b)
C)Figure 18-1(c)
D)none of these

Question 10

VRF equals ________ in Figure 18-1(c).

A)
B)
C)
D)

Question 11

Which one of these op-amp terminals provides an output that is in-phase with the input?

A)offset null
B)non-inverting
C)VCC
D)inverting

Question 12

Which of the amplifiers in Figure 18-1 would be used as a buffer amplifier?

A)Figure 18-1(a)
B)Figure 18-1(b)
C)Figure 18-1(c)
D)none of these

Question 13

An op-ampʹs input offset voltage, VOS, is the differential input voltage required to make the 9)
differential output voltage zero.

Question 14

An op-ampʹs CMRR is usually expressed in dB.

Question 15

If , Ri equals ________.

A)1 kΩ
B)10 kΩ
C)120 Ω
D)100 kΩ

Question 16

The open-loop voltage gain of an op-amp is very large.

Question 17

The slew rate of an op-amp is determined by the frequency response of the internal amplifiers.

Question 18

What trouble in the amplifier in Figure 18-1(c) could cause the voltage gain to drop to 1?

A) is open
B) s open
C)the power is off
D)VOUT is grounded

Question 19

Identify the non-inverting amplifier in Figure 18-1.

A)Figure 18-1(a)
B)Figure 18-1(b)
C)Both A and B
D)Neither of these

Question 20

Practical op-amps come reasonably close to the requirements for an ideal amplifier.

Question 21

If an op-ampʹs output increases 8 V every 12 μs in response to a step input voltage, the slew rate equals ________.

A)
B)
C)0.75 V/μs
D)1.5 V/μs

Question 22

If , the voltage gain equals ________.

A)-15.7
B)-1
C)-14.7
D)infinite

Question 23

What trouble in the amplifier in Figure 18-1(b) could cause the voltage between the inverting and non-inverting inputs to nearly equal 0 V?

A) is open.
B) s open.
C)The power is off.
D)There is no problem; 0 V is normal.

Question 24

A typical op-amp has ________ input impedance and ________ output impedance.

A)low, low
B)low, high
C)high, low
D)high, high

Question 25

If , the voltage gain equals ________.

A)-5
B)-2
C)-0.5
D)0

Question 26

What trouble in the amplifier in Figure 18-1(c) could cause the output voltage to clip severely?

A)The input signal is too large.
B)The power is off.
C)The amplifierʹs gain is too low.
D)The input signal is too small for the amplifier to respond.

Question 27

If , the voltage gain equals ________.

A)-1
B)-68.2
C)-69.2
D)infinite

Question 28

If , the voltage gain equals ________.

A)15.1
B)16
C)15
D)16.1

Question 29

One characteristic of a noninverting amplifier is a ________.

A)voltage gain slightly more than an inverting amplifier with the same values
B)very low input impedance
C)voltage gain of one
D)high output impedance

Question 30

If and VOUT = 5 V in a noninverting op-amp, equals ________.

A)50 mV
B)500 mV
C)495 mV
D)49.5 mV

Question 31

Which one of these devices produces amplifiers with characteristics close to those of an ideal amplifier?

A)Op-amp
B)BJT
C)JFET
D)MOSFET

Question 32

A CMRR of 35,000 equals a decibel CMRR of ________.

A)88 dB
B)-91 dB
C)91 dB
D)35000 dB

Question 33

The input impedance of the amplifier in Figure 18-1(b) is ________.

A)very high.
B)very low
C)

Question 34

The circuit in Figure 18-1(a) is used as a(n) ________.

A)inverting amplifier
B)buffer amplifier
C)oscillator
D)high gain amplifier

Question 35

The circuit in Figure 18-1(c) is known as the ________.

A)open-loop amplifier
B)voltage follower amplifier
C)non-inverting amplifier
D)inverting amplifier

Question 36

If , the voltage gain equals ________.

A)-0.066
B)-16
C)-15
D)-1

Question 37

If in Figure 18-1(c), Ri equals ________.

A)
B)
C)
D)

Question 38

If , the voltage gain equals ________.

A)25.5
B)25
C)26
D)26.5

Question 39

To build an amplifier with a input impedance and a voltage gain of 40, use the ________ amplifier,

A)
B)
C)
D)

Question 40

If , the voltage gain equals ________.

A)1.01
B)470
C)94
D)95

Question 41

The op-amp configuration with the highest possible input impedance is:

A)voltage-follower op-amp.
B)inverting op-amp.
C)non-inverting op-amp.
D)differential op-amp.

Question 42

A CMRR of 90,000 equals a decibel CMRR of ________.

A)-99 dB
B)99 dB
C)90,000 dB
D)91 dB

Question 43

If and VOUT = 5 V in a noninverting op-amp, equals ________.

A)0.0099
B)99
C)101
D)1

Question 44

If you know an op-ampʹs open-loop gain only, you can determine the closed-loop gain of:

A)a voltage follower op-amp.
B)an non-inverting op-amp.
C)an inverting op-amp.
D)all of these.

Question 45

Which of these amplifiers provides a high input resistance and a variable gain?

A)open-loop amp
B)non-inverting amp with a rheostat as Rf.
C)inverting amp
D)voltage-follower amp

Question 46

To use an op-amp as a buffer, use the ________.

A)voltage follower amplifier
B)differential amplifier
C)non-inverting amplifier
D)inverting amplifier

Question 47

A diff-amp with two out-of-phase signal voltages applied to the two inputs is called:

A)differential input.
B)differential output.
C)phase inverter output.
D)phase inverter input.

Question 48

If = 25,000 in an inverting op-amp, A equals ________.

A)-250
B)-0.01
C)100
D)-100

Question 49

The feedback attenuation of a voltage follower op-amp is:

A)
B)= 1.
C)> 1.
D)< 1.

Question 50

If an op-ampʹs output increases 6 V every 18 μs in response to a step input voltage, the slew rate equals ________.

A)
B)
C)
D)

Question 51

A diff-amp with 1 input grounded and the signal voltage applied only to the other input is called:

A)single ended.
B)single output.
C)single input.
D)grounded input.

Question 52

A practical differential amplifier provides:

A)very high input impedance.
B)very high differential voltage gain > 1000.
C)very small common mode gain < 1.
D)all of these.

Question 53

Which one of these characteristics do an op-amp and a MOSFET have in common?

A)high input impedance
B)high current gain
C)high CMRR
D)high voltage gain

Question 54

To build an amplifier with a input impedance and a voltage gain of 41, use the ________ amplifier,

A)
B)
C)
D)

Question 55

A diff-amp with two identical signal voltage applied to the two inputs is called:

A)same phase input.
B)common mode output.
C)common mode input.
D)same signal input.

Question 56

A CMRR of 10,000 means that the op-amp provides that:

A)the common mode input is greatly reduced.
B)
C)the differential input is greatly amplified.
D)all of these.

Question 57

One characteristic of a voltage follower is its ________.

A)high output impedance
B)large voltage gain
C)phase inversion
D)non-inversion

Question 58

The distinguishing characteristic of the voltage follower configuration is:

A)very high input impedance.
B)voltage gain of unity.
C)non-inverting output.
D)all of the above