oscillators Mcqs
1. An important limitation of a crystal oscillator is____________?
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A. Its high output

B. Less availability of quartz crystal

C. Its low output

D. Its high Q

2. In an LC transistor oscillator, the active device is___________?
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A. None of the above

B. Transistor

C. LC tank circuit

D. Biasing circuit

3. An oscillator differs from an amplifier because it_____________?
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A. Requires no d.c. supply

B. Has more gain

C. Requires no input signal

D. Always has the same input

4. In a certain oscillator Av = 50. The attention of the feedback circuit must be___________?
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A. 1

B. 10

C. 1

D. 02
5. A second condition for oscillations is____________?
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A. The attention of the feedback circuit must be one-third

B. A gain of 1 around the feedback loop

C. No gain around the feedback loop

D. The feedback circuit must be capacitive

6. In Colpitts oscillator, feedback is obtained___________?
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A. By a tickler coil

B. A. By magnetic induction

C. From the centre of split capacitors

D. None of the above

7. An oscillator produces___________oscillations?
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A. None of the above

B. Modulated

C. Damped

D. Undamped
8. If the crystal frequency changes with temperature, we say that crystal has___________temperature coefficient?
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A. Zero

B. None of the above

C. Negative

D. Positive
9. The application where one would most likely find a crystal oscillator is____________?
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A. Radio receiver

B. Radio transmitter

C. AF sweep generator

D. None of the above

10. An LC oscillator cannot be used to produce ____________frequencies?
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A. Audio

B. Very high

C. Very low

D. High

11. In an LC oscillator, if the value of L is increased four times, the frequency of oscillations is __________?
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A. Decreased 4 times

B. Increased 4 times

C. Decreased 2 times

D. Increased 2 times

12. The Q of the crystal is of the order of____________?
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A. 1000

B. 100

C. More than 10,000

D. 50

13. The signal generator generally used in the laboratories is___________oscillator?
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A. Hartely

B. Phase shift

C. Crystal

D. Wien-bridge
14. An oscillator employs___________feedback?
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A. Neither positive nor negative

B. Data insufficient

C. Positive

D. Negative

15. One condition for oscillation is_____________?
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A. A gain around the feedback loop of one-third

B. A gain around the feedback loop of less than 1

C. A phase shift around the feedback loop of 180o

D. A phase shift around the feedback loop of 0o
16. The crystal oscillator frequency is very stable due to___________of the crystal?
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A. Low Q

B. Vibrations

C. High Q

D. Rigidity

17. Hartley oscillator is commonly used in______________?
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A. Radio receivers

B. Radio transmitters

C. None of the above

D. TV receivers

18. Quartz crystal is most commonly used in crystal oscillators because:____________?
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A. It has superior electrical properties

B. None of the above

C. It is easily available

D. It is quite inexpensive

19. An oscillator converts __________?
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A. mechanical power into a.c. power

B. power into a.c. power

C. power into d.c. power

D. none of the above

20. In a Wien-bridge oscillator, if the resistances in the positive feedback circuit are decreased, the frequency____________?
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A. Increases

B. Insufficient data

C. Decreases

D. Remains the same

21. In an LC circuit, when the capacitor is maximum, the inductor energy is____________?
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A. Maximum

B. None of the above

C. Half-way between maximum and minimum

D. Minimum
22. In a phase shift oscillator, the frequency determining elements are _______________?
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A. R and C

B. L and C

C. None of the above

D. R, L and C

23. In an LC oscillator, the frequency of oscillator is____________L or C?
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A. Proportional to square of

B. Directly proportional to

C. Inversely proportional to square root of

D. Independent of the values of

24. A Wien bridge oscillator uses___________feedback?
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A. Only positive

B. Only negative

C. Both positive and negative

D. None of the above

25. In a phase shift oscillator, we use____________RC sections?
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A. Two

B. Four

C. None of the above

D. Three
26. The piezoelectric effect in a crystal is___________?
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A. A change in resistance because of temperature

B. A change in frequency because of temperature

C. None of the above

D. A voltage developed because of mechanical stress
27. ____________is a fixed frequency oscillator?
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A. Hartely-oscillator

B. Phase-shift oscillator

C. Colpitts oscillator

D. Crystal oscillator
28. For an oscillator to properly start, the gain around the feedback loop must initially be_________?
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A. Greater than 1

B. 1

C. Less than 1

D. Equal to attenuation of feedback circuit