Oscillators

21. In Colpitt’s oscillator, feedback is obtained _________..

1. By magnetic induction
2. By a tickler coil
3. From the centre of split capacitors
4. None of the above

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22. One condition for oscillation is …_________.

1. A phase shift around the feedback loop of 180o
2. A gain around the feedback loop of one-third
3. A phase shift around the feedback loop of 0o
4. A gain around the feedback loop of less than 1

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23. Quartz crystal is most commonly used in crystal oscillators because …_________.

1. It has superior electrical properties
2. It is easily available
3. It is quite inexpensive
4. None of the above

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24. The application where one would most likely find a crystal oscillator is _________.

1. Radio receiver
2. Radio transmitter
3. AF sweep generator
4. None of the above

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25. The crystal oscillator frequency is very stable due to _________. of the crystal

1. Rigidity
2. Vibrations
3. Low Q
4. High Q

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26. The piezoelectric effect in a crystal is _________.

1. A voltage developed because of mechanical stress
2. A change in resistance because of temperature
3. A change in frequency because of temperature
4. None of the above

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27. The Q of the crystal is of the order of _________.

1. 100
2. 1000
3. 50
4. More than 10,000

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28. The signal generator generally used in the laboratories is …_________. oscillator

1. Wien-bridge
2. Hartely
3. Crystal
4. Phase shift

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