Multistage Transistor Amplifiers

31. The output of a microphone is rated at -52 db. The reference level is 1V under specified conditions. What is the output voltage of this microphone under the same sound conditions?

1. 5 mV
2. 2 mV
3. 8 mV
4. 5 mV

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32. The power output of an audio system is 18 W. For a person to notice an increase in the output (loudness or sound intensity) of the system, what must the output power be increased to ?

1. 2 W
2. 6 W
3. 68 W
4. None of the above

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33. The purpose of RC or transformer coupling is to __________

1. Block a.c.
2. Separate bias of one stage from another
3. Increase thermal stability
4. None of the above

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34. The total gain of a multistage amplifier is less than the product of the gains of individual stages due to __________

1. Power loss in the coupling device
2. Loading effect of the next stage
3. The use of many transistors
4. The use of many capacitors

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35. The upper or lower cut off frequency is also called __________ frequency

1. Resonant
2. Sideband
3. 3 db
4. None of the above

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36. The value of emitter capacitor CE in a multistage amplifier is about __________

1. 1 μF
2. 100 pF
3. 0.01 μF
4. 50 μF

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37. Transformer coupling is generally employed when load resistance is __________

1. Large
2. Very large
3. Small
4. None of the above

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38. Transformer coupling is used for __________ amplification

1. Power
2. Voltage
3. Current
4. None of the above

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39. Transformer coupling provides high efficiency because __________

1. Collector voltage is stepped up
2. c. resistance is low
3. collector voltage is stepped down
4. none of the above

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40. When a multistage amplifier is to amplify d.c. signal, then one must use __________ coupling

1. RC
2. Transformer
3. Direct
4. None of the above

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