Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Figure 19–5
1)
The curve in Figure 19–5 is from a ________ and its lower cutoff frequency equals ________.
1)
A)
two–pole high–pass filter, 1500 Hz
B)
band–reject filter, 450 kHz
C)
band–pass filter, 450 Hz
D)
band–pass filter, 822 Hz
2)
The frequency response curve in Figure 19–5 represents the output from the ________, and the
bandwidth is ________.
2)
A)
band–reject filter, 1050 kHz
B)
band–pass filter, 1050 Hz
C)
band–pass filter, 678 Hz
D)
two–pole high–pass filter, 1050 Hz
Explanation:
Figure 19–4
3)
The circuit in Figure 19–4 is known as the ________ and it rolls off at a rate of ________.
3)
A)
Butterworth low–pass filter, –20 dB/decade
B)
Butterworth high–pass filter, –40 dB/decade
C)
Butterworth high–pass filter, –20 dB/decade
D)
Butterworth low–pass filter, –40 dB/decade
4)
If the inputs are –7.1 V and 12 V in Figure 19–2(a), what is the output voltage?
4)
A)
–19.1 V
B)
19.1 V
C)
–4.9 V
D)
4.9 V
Figure 19–3
5)
If R = 56 k and C = 0.05 µF in Figure 19–3, fCO equals ________.
5)
A)
56.8 Hz
B)
300 Hz
C)
568 Mz
D)
3.0 Hz
6)
Short–circuit or overload protection is an integral part of ________.
6)
A)
most op–amps
B)
most TRIACs
C)
most three–terminal regulators
D)
most JFETs
Figure 19–3
7)
If VIN equals 22 V in Figure 19–3, VOUT at the fCO equals ________.
7)
A)
15.64 V
B)
0
C)
7.79 V
D)
31.1 V
8)
If all four input resistors to a summing amplifier are 2.2 k, the feedback resistor is 2.2 k and all
four input voltages are –2 V, the output voltage equals ________.
8)
A)
10 V
B)
8 V
C)
2 V
D)
2.2 V
9)
The purpose of a comparator is to ________.
9)
A)
amplify an input voltage
B)
maintain a constant output when the dc input voltage changes
C)
detect the occurrence of a changing input voltage
D)
produce a change in output when an input voltage equals a reference voltage
10)
The input frequency of a single–pole, low–pass active filter increases from 1.5 kHz to 150 kHz. If
the critical frequency is 1.5 kHz, the gain decreases by ________.
10)
A)
60 dB
B)
40 dB
C)
3 dB
D)
20 dB
11)
If VIN = 4.2 V in Figure 19–1, VOUT equals ________.
11)
A)
13 V
B)
–13 V
C)
–0.8 V
D)
0.8 V
12)
If an inverting amplifier has a capacitor in the feedback loop, the circuit is known as the ________.
When a square wave input is applied, the output is a ________ wave.
12)
A)
integrator, square
B)
open loop, triangle
C)
integrator, triangle
D)
differentiator, triangle
13)
At the cutoff frequency of a filter circuit, the output voltage is:
13)
A)
–20 dB.
B)
–40 dB.
C)
–10 dB.
D)
–3 dB.
14)
If R = 1.5 k and C = 256 pF in Figure 19–3, the fCO equals ________.
14)
A)
414 kHz
B)
41.4 kHz
C)
257 Hz
D)
25.7 Hz
15)
If R = 47 k and C = 0.02 µF in Figure 19–3, fCO equals ________.
15)
A)
51.9 Hz
B)
5.19 Hz
C)
169 Hz
D)
16.9 Hz
16)
In a scaling adder, the ________.
16)
A)
ratio RF/RIN must be the same for each input
B)
input resistors have values depending on the assigned weight of each input
C)
input resistors are all the same value
D)
input resistors are all different values
17)
If the inputs are 8.4 V and 1.2 V in Figure 19–2(a), the output voltage equals ________.
17)
A)
10.08 V
B)
9.6 V
C)
–9.6 V
D)
7.2 V
18)
If the inputs are 1.2 V, –0.5 V and 2.4 V in Figure 19–2(b), what is the output voltage?
18)
A)
13 V
B)
–6.2 V
C)
6.2 V
D)
–4.1 V
19)
Using op–amps in a triangular wave oscillator results in a:
19)
A)
triangular wave output.
B)
square wave output.
C)
function generator output.
D)
all of these.
20)
The output of an op–amp differentiator depends on the values of ________ and ________.
20)
A)
RIN, CF
B)
CIN, CF
C)
RIN, RF
D)
CIN, RF
21)
If 22 V in the pass–band is input to the circuit in Figure 19–4, what is the output voltage at a
frequency that is 1 decade higher?
21)
A)
22 V
B)
15.5 V
C)
31.1 V
D)
7.75 V
22)
What change causes the circuit in Figure 19–2(b) to output the average of the three input voltages?
22)
A)
Change the input resistors to 3.3 k.
B)
Change to a different type of op–amp.
C)
Change the feedback resistor to 3.3 k.
D)
Change the feedback resistor to 10 k.
Figure 19–3
23)
If R = 1.2 k and C = 0.005 µF in Figure 19–3, the fCO equals ________.
23)
A)
650 Hz
B)
2.65 kHz
C)
65 Hz
D)
26.5 kHz
24)
If the output voltage is 27.4 V at 822 Hz in Figure 19–5, what is the output voltage at 1.5 kHz?
24)
A)
19.4 V
B)
6.85 V
C)
27.4 V
D)
13.7 V
Figure 19–4
25)
If 22 V in the pass–band is input to the circuit in Figure 19–4, what is the output voltage at fCO?
25)
A)
7.75 V
B)
15.6 V
C)
31.1 V
D)
8.92 V
26)
The basic op–amp square wave oscillator is actually a:
26)
A)
sine wave oscillator.
B)
resistor–capacitor (RC) time constant oscillator.
C)
Wein–bridge oscillator.
D)
all of these.
Figure 19–4
27)
In Figure 19–4, if the frequency is decreased from the pass band to 1 decade below fCO, the output
voltage drops to ________.
27)
A)
–6 dB
B)
–40 dB
C)
–3 dB
D)
–20 dB
28)
If VIN= 70 VP in Figure 19–3, the output voltage at fCO equals ________.
28)
A)
49.5 VP
B)
44.2 VP
C)
0 VP
D)
13 VP
Figure 19–3
Figure 19–1
29)
If VIN = –3 V in Figure 19–1, VOUT equals ________.
29)
A)
1 V
B)
–13 V
C)
13 V
D)
–1 V
30)
If VIN = –2 V in Figure 19–1, VOUT equals ________.
30)
A)
3 V
B)
13 V
C)
–13 V
D)
–3 V
31)
In an inverting input op–amp integrator supplied with a square wave pulse or a step, the output is
a:
31)
A)
same phase ramp.
B)
sine wave.
C)
opposite phase ramp.
D)
opposite phase square wave.
Figure 19–5
32)
If the output voltage is 6 V at 1500 Hz in Figure 19–5, what is the output voltage at 822 Hz?
32)
A)
8.49 V
B)
1.06 V
C)
4.24 V
D)
2.12 V
33)
In a series voltage regulator, the four circuit blocks are:
33)
A)
error detector, reference voltage, series regulator, sampling circuit.
B)
reference voltage, series load, reference voltage, current limiter.
C)
control element, reference voltage, error detector, sampling circuit.
D)
control element, reference voltage, error detector, current limiter.
C
34)
If all four input resistors to a summing amplifier are 2.2 k and the feedback resistor is 2.2 k,
then the gain equals ________.
34)
A)
4
B)
1
C)
2.2
D)
unknown
B
35)
In a filter circuit, the terminology single pole means:
35)
A)
one fixed contact.
B)
one single RC circuit.
C)
one movable contact.
D)
two cascaded RC circuits.
B
A
Figure 19–1
36)
If VIN equals 4 V in Figure 19–1, VOUT equals ________.
36)
A)
–1 V
B)
–13 V
C)
1 V
D)
13 V
37)
In a voltage–controlled oscillator (VCO), the output signal frequency is dependent on:
37)
A)
the value of a resistor–capacitor combination.
B)
the value of an applied voltage.
C)
the value of a capacitor.
D)
the value of a resistor.
38)
A series and a shunt regulator are differentiated by the circuit placement of a:
38)
A)
series resistor versus parallel resistor.
B)
series transistor versus parallel transistor.
C)
series reference voltage versus parallel reference voltage.
D)
none of these.
39)
A three–terminal voltage regulator ________.
39)
A)
comes in a variety of voltage and current ratings
B)
is available in both positive and negative voltage ratings
C)
is very durable
D)
all of the above
Figure 19–4
40)
The prime characteristic of the filter in Figure 19–4 is ________.
40)
A)
the filter roll–off below the corner frequency is 40 dB/decade
B)
it only works in a high–pass configuration
C)
it has the largest response of any filter type
D)
nothing special
41)
If the inputs are 4.1 V, –0.7 V and 3.1 V in Figure 19–2(b), the output voltage equals ________.
41)
A)
–13 V
B)
–6.5 V
C)
6.5 V
D)
13 V
Explanation:
Figure 19–5
42)
If VOUT equals 12 V at 822 Hz in Figure 19–5, the output voltage equals ________ at 450 Hz.
42)
A)
1.06 V
B)
4.24 V
C)
2.12 V
D)
8.49 V
43)
In a Wein–bridge op–amp oscillator, the output is a repetitive:
43)
A)
sine wave.
B)
triangular wave.
C)
square wave.
D)
all of these.
44)
If R = 22 k and C = 0.05 µF in Figure 19–3, fCO equals ________.
44)
A)
48 Hz
B)
4.8 Hz
C)
145 Hz
D)
1.45 kHz
Figure 19–1
45)
If VIN= 8.3 V in Figure 19–1, VOUT equals ________.
45)
A)
13 V
B)
–13 V
C)
3.3 V
D)
–3.3 V
46)
If the two input voltages are 9.2 V and 0.7 V in Figure 19–2(a), what is the output voltage?
46)
A)
8.5 V
B)
–9.9 V
C)
–8.5 V
D)
9.9 V
47)
In an inverting input op–amp, differentiator supplied with a ramp or triangular wave, the output is
a:
47)
A)
same phase square wave.
B)
opposite phase square wave.
C)
sine wave.
D)
opposite phase ramp.
Figure 19–2
48)
A series–pass voltage regulator has ________.
48)
A)
an error amplifier
B)
a shunt regulator
C)
a load
D)
all of these
49)
If VIN equals 8 V in Figure 19–1, VOUT equals ________.
49)
A)
–1 V
B)
13 V
C)
–13 V
D)
1 V
50)
In Figure 19–3, what will change the circuit into a high–pass filter?
50)
A)
placing the capacitor in the feedback loop
B)
switching the positions of the resistor and capacitor
C)
increasing the value of the resistor
D)
decreasing the value of the capacitor
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
51)
A Wien–bridge oscillator produces an excellent quality square wave.
51)
52)
A series–pass transistor is used in a voltage regulator.
52)
53)
An op–amp comparator can be used to determine when an input voltage crosses a certain reference
voltage.
53)
54)
An op–amp summing amplifier has no limitations on the number of inputs it can handle.
54)
55)
Hartley and Colpitts oscillators can use op–amps.
55)
56)
Butterworth filters are characterized by a linear response in the pass band.
56)
57)
The terminals on a three–terminal regulator are input voltage, output voltage and ground.
57)
58)
Op–amp comparators are often used as zero–level detectors.
58)
59)
A second–order filter rolls–off at 40 dB/decade.
59)
60)
An op–amp integrator will produce a linear increasing output voltage for a constant negative input
voltage until cutoff is reached.
60)
Answer Key
Testname: C19
Answer Key
Testname: C19
20