Electronic Circuits

221. When negative voltage feedback is applied to an amplifier, its output impedance

1. Remains unchanged
2. Decreases
3. Increases
4. Becomes zero

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222. When shock-excited, a crystal will produce alternating emf longer than an LC circuit because

1. has greater mechanical strength
2. has fewer losses
3. is small-sized
4. is very rigid

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223. When the collector resistor in a common emitter amplifier is increased in value the voltage gain

1. Increases
2. Decreases
3. Remain the same
4. Becomes erratic

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224. When the collector supply is 5V, then collector cut off voltage under dc condition is

1. 20V
2. 10V
3. 2.5V
4. 5V

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225. When the gain is 20 without feedback and 12 with negative feedback, feedback factor is

1. 0.033
2. 3l5
3. 5l3
4. 1l5

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226. When the gain versus frequency curve of a transistor amplifier is not flat, _________ distortion is present.

1. Amplitude
2. Frequency
3. Intermodulation
4. Phase

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227. When the non-linear distortion in an amplifier is D without feedback, with negative voltage feedback it will be

1. D/ 1+A β
2. 1+A β l D
3. D (1+A β)
4. D (1-A β)

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228. When the output of an amplifier is 10V and 100mV from the output is fed back to the input, feedback factor is

1. 10
2. 0.1
3. 0.01
4. 0.15

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229. Which amplifier whose output current flows for the entire cycle?

1. Class A
2. Class B
3. Class C
4. Class AB

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230. Which configuration has the lowest current gain?

1. Common-base
2. Common-collector
3. Common-emitter
4. Emitter follower

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