26)
If an op–amp were perfect, the CMRR would
26)
A)
be zero.
B)
approach infinity.
C)
be very small.
D)
be less than one.
Answer:
B
A)
B)
C)
D)
27)
The closed–loop voltage gain of an inverting amplifier equals
27)
A)
the input resistance.
B)
the ratio of the input resistance to the feedback resistance.
C)
the feedback resistance divided by the input resistance.
D)
the open–loop voltage gain.
Answer:
C
A)
B)
C)
D)
28)
Refer to the figure above. The purpose of R1 and R2 is
28)
A)
to set input impedance only.
B)
for bias current compensation.
C)
to set input impedance and voltage gain.
D)
for input offset voltage compensation.
Answer:
C
A)
B)
C)
D)
29)
The voltage gain of an op–amp is unity at the
29)
A)
cutoff frequency.
B)
power bandwidth.
C)
generator frequency.
D)
unity–gain frequency.
Answer:
D
A)
B)
C)
D)
8
30)
Refer to the figure above. Which circuit is the noninverting amplifier?
30)
A)
(a)
B)
(b)
C)
(c)
D)
None of the above.
Answer:
B
A)
B)
C)
D)
31)
When the initial slope of a sine wave is greater than the slew rate,
31)
A)
the output looks exactly like the input.
B)
the op–amp works best.
C)
distortion occurs.
D)
voltage gain is maximum.
Answer:
C
A)
B)
C)
D)
32)
Refer to the figure above. Which circuit has a voltage gain of 20?
32)
A)
(a)
B)
(b)
C)
(c)
D)
None of the above.
Answer:
D
A)
B)
C)
D)
33)
If the unit–gain frequency is 10 MHz and the mid–band open–loop voltage gain is 200,000, the
cutoff frequency is
33)
A)
25 MHz.
B)
5 Hz.
C)
50 Hz.
D)
5 kHz.
Answer:
C
A)
B)
C)
D)
9
34)
There can be no current to ground through
34)
A)
an ordinary ground.
B)
an ac ground.
C)
a mechanical ground.
D)
a virtual ground.
Answer:
D
A)
B)
C)
D)
35)
With negative feedback, the returning signal
35)
A)
is proportional to output current.
B)
is proportional to differential voltage gain.
C)
opposes the input signal.
D)
aids the input signal.
Answer:
C
A)
B)
C)
D)
36)
Refer to (c) in the figure above. Vin = – 60 mV. The value of Vout is
36)
A)
–600 mV.
B)
about 16 V.
C)
660 mV.
D)
600 mV.
Answer:
D
A)
B)
C)
D)
37)
Refer to (c) in the figure above. If Rf is changed to 1 M, the new Acl would be
37)
A)
20.
B)
–20.
C)
–21.
D)
21.
Answer:
B
A)
B)
C)
D)
10
38)
In an op–amp, the CMRR is limited mostly by the
38)
A)
gain–bandwidth product.
B)
the common–mode gain of the op–amp.
C)
tolerance of the resistors.
D)
supply voltages.
Answer:
B
A)
B)
C)
D)
39)
Op–amp noise is highest at low frequencies due to
39)
A)
white noise.
B)
inductive noise.
C)
resistive noise.
D)
1/f noise.
Answer:
D
A)
B)
C)
D)
40)
The voltage follower has a
40)
A)
closed–loop bandwidth of zero.
B)
small open–loop voltage gain.
C)
closed–loop voltage gain of unity.
D)
large closed–loop output impedance.
Answer:
C
A)
B)
C)
D)
41)
Refer to the figure above. If these three circuits were connected as a multiple–stage amplifier, the
total voltage gain would be
41)
A)
1.
B)
21.
C)
10.
D)
210.
Answer:
D
A)
B)
C)
D)
42)
Refer to (a) in the figure above. If this circuit has a Vin = 12 Vp–p, the value of Vout would be
42)
A)
12 Vp–p.
B)
20 V.
C)
–20 V.
D)
8.48 Vp–p.
Answer:
A
A)
B)
C)
D)
11
43)
It takes an op–amp 22 µs to change its output from –15 V to +15 V. The slew rate for this amplifier
is
43)
A)
1.36 V/µs.
B)
0.73 V/µs.
C)
660 V/µs.
D)
0.68 V/µs.
Answer:
A
A)
B)
C)
D)
44)
1/f noise is also known as ________.
44)
A)
white noise
B)
nV Hz
C)
pink noise
D)
noise density
Answer:
C
A)
B)
C)
D)
45)
The feedback fraction “B“
45)
A)
may not equal 1.
B)
is always less than 1.
C)
is usually greater than 1.
D)
may equal 1.
Answer:
B
A)
B)
C)
D)
46)
Refer to the figure above. This op–amp has a slew rate of 1.33 V/µs. How long would it take the
output voltage to change from –12 V to +12 V?
46)
A)
36 µs
B)
16 µs
C)
48 µs
D)
18 µs
Answer:
D
A)
B)
C)
D)
12
47)
Refer to the figure above. Which circuit has a voltage gain of 1?
47)
A)
(a)
B)
(b)
C)
(c)
D)
None of the above.
Answer:
A
A)
B)
C)
D)
48)
The two basic ways of specifying input impedance of an op–amp are
48)
A)
closed–loop and common–mode.
B)
differential and extremely high.
C)
differential and common–loop.
D)
differential and common–mode.
Answer:
D
A)
B)
C)
D)
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
49)
The differential amplifier is used as the input stage of an operational amplifier.
49)
Answer:
True
False
50)
An inverting amplifier has an input resistance equal to the input resistor.
50)
Answer:
True
False
51)
CMRR is the measure of an op–amp’s voltage gain for an inverting amplifier.
51)
Answer:
True
False
52)
Op–amp noise specifications include external sources of noise such as power supply noise.
52)
Answer:
True
False
53)
A voltage follower has a very high input impedance, and is often used as a high voltage gain
amplifier.
53)
Answer:
True
False
13
54)
A good op–amp has high voltage gain, low output impedance, and high input impedance.
54)
Answer:
True
False
14