Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
Refer to the figure above. Which of these circuits is known as a Hartley oscillator?
1)
A)
(a)
B)
(b)
C)
(c)
D)
None of the above.
Answer:
C
Explanation:
A)
B)
C)
D)
1
2)
A Wien–bridge oscillator uses
2)
A)
positive feedback.
B)
negative feedback.
C)
both types of feedback.
D)
an LC tank circuit.
Answer:
C
Explanation:
A)
B)
C)
D)
3)
A stable type of oscillator is
3)
A)
the Clapp oscillator.
B)
the crystal oscillator.
C)
the Hartley oscillator.
D)
None of the above.
Answer:
B
Explanation:
A)
B)
C)
D)
2
4)
Refer to the figure above. Which of these circuits is known as a Clapp oscillator?
4)
A)
(a)
B)
(b)
C)
(c)
D)
None of the above.
Answer:
B
Explanation:
A)
B)
C)
D)
3
5)
One way to recognize a Colpitts oscillator is by the
5)
A)
lead/lag network in the feedback path.
B)
three lag networks in the feedback path.
C)
tapped inductors in the tank circuit.
D)
tapped capacitors in the tank circuit.
Answer:
D
Explanation:
A)
B)
C)
D)
6)
A crystal’s fundamental frequency depends upon
6)
A)
mechanical dimensions.
B)
type of cut.
C)
crystal thickness.
D)
All of the above.
Answer:
D
Explanation:
A)
B)
C)
D)
7)
The phase–shift oscillator usually has
7)
A)
two lead or lag circuits.
B)
three lead or lag circuits.
C)
no feedback loop.
D)
no RC sections.
Answer:
B
Explanation:
A)
B)
C)
D)
8)
Which type of LC oscillator uses a tickler coil in the feedback path?
8)
A)
Armstrong
B)
Clapp
C)
Hartley
D)
Colpitts
Answer:
A
Explanation:
A)
B)
C)
D)
9)
A circuit that can change the frequency of oscillation with an application of a dc voltage is
sometimes called a(n)
9)
A)
crystal oscillator.
B)
astable multivibrator.
C)
voltage–controlled oscillator.
D)
Hartley oscillator.
Answer:
C
Explanation:
A)
B)
C)
D)
4
10)
Which of the following is not an essential requirement of a feedback oscillator?
10)
A)
Positive feedback network
B)
Amplifier circuit
C)
Negative feedback network
D)
Phase shift around the feedback loop of 0°
Answer:
C
Explanation:
A)
B)
C)
D)
11)
The Q of a crystal
11)
A)
is extremely high.
B)
is extremely low.
C)
is about 10 or so in most cases.
D)
None of the above.
Answer:
A
Explanation:
A)
B)
C)
D)
12)
When Q decreases in a Colpitts oscillator, the frequency of oscillation
12)
A)
increases.
B)
is unpredictable.
C)
remains the same.
D)
decreases.
Answer:
D
Explanation:
A)
B)
C)
D)
13)
Nonsinusoidal oscillators produce
13)
A)
sine waves only.
B)
triangle waves.
C)
square waves.
D)
Either B or C above.
Answer:
D
Explanation:
A)
B)
C)
D)
14)
In a Colpitts oscillator, which component(s) determine the feedback fraction, B?
14)
A)
The RF choke in the collector circuit
B)
The inductor in the tank circuit
C)
The capacitors C1 and C2 in the tank circuit
D)
The resistors R1 and R2 in the base circuit
Answer:
C
Explanation:
A)
B)
C)
D)
5
15)
Refer to the figure above. If C5 were to open
15)
A)
the resonant frequency would be higher than normal.
B)
the resonant frequency would be lower than normal.
C)
there would be no signal present at Vout.
D)
the circuit would draw no current from +Vcc.
Answer:
C
Explanation:
A)
B)
C)
D)
16)
In order for feedback oscillators to operate properly, the gain has to be
16)
A)
stabilized.
B)
nonlinear.
C)
self–adjusting.
D)
1/4.
Answer:
C
Explanation:
A)
B)
C)
D)
17)
The voltage that starts a feedback oscillator is caused by
17)
A)
thermal noise in resistors.
B)
ripple from the power supply.
C)
the input signal from a generator.
D)
positive feedback.
Answer:
A
Explanation:
A)
B)
C)
D)
6