Electronic Circuits

191. What is the phase difference between voltage across collector load and signal voltage in a common emitter amplifier?

1. 0°
2. 270°
3. 180°
4. 90°

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192. What is the piezoelectric effect in a crystal?

1. Voltage is developed because of mechanical stress
2. Change in resistance because of temperature
3. Change of frequency because of temperature
4. Current is developed due to force applied

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193. What is the point of intersection of dc and ac load lines called?

1. Operating point
2. Cut off point
3. Saturation point
4. Breakdown

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194. What is the purpose of capacitors in a transistor amplifier?

1. To protect the transistor
2. To cool the transistor
3. To couple or bypass ac component
4. To provide biasing

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195. What is the purpose of dc conditions in a transistor?

1. To reverse bias the emitter
2. To forward bias the emitter
3. To set up operating point
4. To turn on the transistor

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196. What is the purpose of RC or transformer coupling?

1. To block ac
2. To separate bias of one stage from another
3. To increase thermal stability
4. To block dc

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197. What is the purpose of the bypass capacitor in a common-emitter amplifier?

1. It increases voltage gain
2. It decreases voltage gain
3. It provides ac grounding
4. No effect in the circuit

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198. What is the purpose of the emitter capacitor?

1. To forward bias the emitter
2. To reduce noise in the amplifier
3. To avoid drop in gain
4. To stabilize emitter voltage

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199. What is the ratio of output to input impedance of a CE amplifier?

1. Very low
2. Very high
3. Moderate
4. Approximately 1

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200. What is the reason why RC coupling is not used to amplify extremely low frequencies?

1. There is considerable power loss
2. Electrical size of coupling capacitor becomes very large
3. There is a hum in the output
4. Electrical size of coupling capacitor becomes very small

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