Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
The unity–gain frequency (fT) equals the product of mid–range voltage gain (AV(mid)) and the
1)
A)
compensating capacitance.
B)
load resistance.
C)
fcu.
D)
BW.
Answer:
Explanation:
A)
B)
C)
D)
2)
Refer to the figure above. If the output voltage at the upper cutoff frequency was 7.19 Vp–p, the
output voltage that would be expected at the lower cutoff frequency is
2)
A)
2.11 Vp–p.
B)
10.17 Vp–p.
C)
7.19 Vp–p.
D)
5.08 Vp–p.
Answer:
Explanation:
A)
B)
C)
D)
3)
The cutoff frequency of a low pass filter occurs at
3)
A)
+3 dB.
B)
–20 dB.
C)
–5 dB.
D)
–3 dB.
Answer:
Explanation:
A)
B)
C)
D)
1
4)
Refer to the figure above. The capacitance Cbc affects
4)
A)
high–frequency response.
B)
mid–range response.
C)
low–frequency response.
D)
nothing.
Answer:
Explanation:
A)
B)
C)
D)
5)
A roll–off of 20 dB per decade is equivalent to a roll–off of ________ per octave.
5)
A)
6 dB
B)
13 dB
C)
3 dB
D)
12 dB
Answer:
Explanation:
A)
B)
C)
D)
6)
At low frequencies, the coupling capacitors produce a decrease in
6)
A)
generator resistance.
B)
generator voltage.
C)
voltage gain.
D)
input resistance.
Answer:
Explanation:
A)
B)
C)
D)
7)
The fc of a certain RC network that has values of R = 470 and C = 0.005 µF is
7)
A)
67.7 kHz.
B)
213 kHz.
C)
12 kHz.
D)
425 kHz.
Answer:
Explanation:
A)
B)
C)
D)
2
8)
If an amplifier has an Rin = 950 , and a coupling capacitor of value 3.3 µF, the approximate cutoff
frequency would be
8)
A)
50.8 kHz.
B)
5.08 Hz.
C)
50.8 Hz.
D)
508 Hz.
Answer:
Explanation:
A)
B)
C)
D)
9)
Refer to the figure above. The output voltage at fcl is 22 mV. Ideally, Vout at the midpoint
frequency would be
9)
A)
22 mV.
B)
31.1 mV.
C)
17 mV.
D)
Not enough information to determine.
Answer:
Explanation:
A)
B)
C)
D)
10)
At the lower or upper cutoff frequency, the voltage gain is
10)
A)
0.995 Avmid.
B)
0.5 Avmid.
C)
0.707 Avmid.
D)
0.35 Avmid.
Answer:
Explanation:
A)
B)
C)
D)
11)
Semilog graph paper has
11)
A)
two (2) logarithmic axes.
B)
two (2) linear axes.
C)
one horizontal linear axis and one vertical logarithmic axis.
D)
one vertical linear axis and one logarithmic horizontal axis.
Answer:
Explanation:
A)
B)
C)
D)
3
12)
Refer to the figure above. High frequency response is affected by
12)
A)
C3.
B)
CBE.
C)
RC.
D)
All of the above.
Answer:
Explanation:
A)
B)
C)
D)
13)
The frequency response of an amplifier is a graph of
13)
A)
output voltage versus frequency.
B)
input voltage versus frequency.
C)
voltage versus current.
D)
voltage versus time.
Answer:
Explanation:
A)
B)
C)
D)
14)
At the unity–gain frequency, the open–loop voltage gain is
14)
A)
zero.
B)
Amid.
C)
very large.
D)
1.
Answer:
Explanation:
A)
B)
C)
D)
15)
In the midband of a CE amplifier
15)
A)
the Miller effect has maximum influence.
B)
the voltage gain is maximum.
C)
the emitter is not at ac ground.
D)
the coupling and bypass capacitors appear open.
Answer:
Explanation:
A)
B)
C)
D)
4
16)
Refer to the figure above. If RL increases in value, the output voltage would
16)
A)
increase.
B)
remain the same.
C)
decrease.
D)
Cannot be determined.
Answer:
Explanation:
A)
B)
C)
D)
17)
If an amplifier has an output voltage of 12.7 Vp–p at the midpoint of the frequency range, the
output voltage at the cutoff frequency would be
17)
A)
4.49 Vp–p.
B)
5.89 Vp–p.
C)
8.98 Vp–p.
D)
12.7 Vp–p.
Answer:
Explanation:
A)
B)
C)
D)
18)
Which of the following capacitances affects the high frequency response of an amplifier?
18)
A)
Internal pn junction capacitance
B)
Stray wiring capacitance
C)
Coupling and bypass capacitors
D)
Both A and B above.
Answer:
Explanation:
A)
B)
C)
D)
19)
If the value of a feedback capacitor is 50 pF, what is the input Miller capacitance when AV= 200?
19)
A)
10 nF
B)
10 µF
C)
100 µF
D)
1 µF
Answer:
Explanation:
A)
B)
C)
D)
5
20)
At low frequencies, the emitter–bypass capacitor
20)
A)
increases the output voltage.
B)
has minimum XC.
C)
increases the voltage gain.
D)
is no longer an ac short.
Answer:
Explanation:
A)
B)
C)
D)
21)
The critical frequencies of an amplifier are the frequencies where the output voltage is
21)
A)
zero.
B)
half of Vmid.
C)
0.707 of Vmid.
D)
0.25 of Vmid.
Answer:
Explanation:
A)
B)
C)
D)
22)
Raising the frequency of 1 kHz by 2 octaves results in a frequency of
22)
A)
250 Hz.
B)
4 kHz.
C)
500 Hz.
D)
2 MHz.
Answer:
Explanation:
A)
B)
C)
D)
23)
If the power gain doubles, the decibel power gain increases by
23)
A)
a factor of 2.
B)
3 dB.
C)
10 dB.
D)
6 dB.
Answer:
Explanation:
A)
B)
C)
D)
6