1. The capacitors used in filter circuits of power supplies having output voltage more then 450 V mainly are
(a) ceramic capacitors.
(b) electrolytic capacitors.
(c) mica capacitors.
(d) paper capacitors.
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2. For the normal operation, a varactor diode is always
(a) forward biased.
(b) reverse biased.
(c) needed to input supply.
(d) none of the above.
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3. If current flowing through a circuit or device increases as the applied voltage is increased, we say that the circuit or device has
(a) inductive nature.
(b) capacitive nature.
(c) positive resistance.
(d) negative resistance.
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4. Varactor diode act as a
(a) variable capacitor.
(b) voltage regulator.
(c) rectifier.
(d) all of the above.
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5. Voltage power supplies use a high resistance across the output of the supply. That resistance is called
(a) high Voltage resistors.
(b) potentiometers.
(c) bleeder resistors.
(d) holding resistors.
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6. Sometime a capacitor is placed in series with the primary of a transformer because
(a) it reduce the ripples in signal.
(b) it raises the power factor of the circuit.
(c) it reduced the noise level.
(d) all of the above.
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7. The capacitors used in filter circuits of power supply having output voltage less than 100 V are
(a) paper capacitors.
(b) ceramic capacitors.
(c) electrolytic capacitors.
(d) variable capacitor.
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8. The common collector collection of a transistor has
(a) very high output resistance.
(b) very low input resistance.
(c) very high input resistance.
(d) none of the above.
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9. The common emitter transistors are used for
(a) high frequency applications.
(b) audio frequency applications.
(c) impedance Matching.
(d) none of the above.
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10. Input resistance of a common base transistor is
(a) zero.
(b) low.
(c) high.
(d) very high.
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11. The common collector transistor are used for
(a) high frequency applications.
(b) audio frequency applications.
(c) low frequency applications.
(d) impedance Matching.
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12. The common base transistors are used for
(a) high frequency applications.
(b) audio frequency applications.
(c) low frequency applications.
(d) impedance Matching.
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13. Vacuum tubes are preferred for the amplification of
(a) low power signals.
(b) low frequency signals.
(c) audio frequency signals.
(d) high power and high frequency signals.
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14. In cutoff state, the collector current in a transistor is
(a) approximately zero.
(b) low.
(c) high.
(d) approaches infinity.
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15. What happened to the base current if base of a transistor is made thick?
(a) base current will decrease.
(b) base current will remain same.
(c) base current will increase.
(d) base current will zero.
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