AFCAT: Electronics MCQs (Practice_Test 1 of 13)

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  1. Removing bypass capacitor across the emitter leg resistor in a CE amplifier causes

    1. increase in current gain

    2. decrease in current gain

    3. increase in voltage gain

    4. decrease in voltage gain

    Answer: d

  2. The minimum number of flip-flops required to construct a mod-75 counter is

    1. 5

    2. 6

    3. 7

    4. 8

    Answer: c

  3. The important characteristic of emitter-follower is

    1. High input impedance and high output impedance

    2. High input impedance and low output impedance

    3. Low input impedance and low output impedance

    4. Low input impedance and high output impedance

    Answer: b

  4. When an amplifier is provided with current series feedback, its

    1. Input impedance increases and output impedance decreases

    2. Input and output impedance both decrease

    3. Input impedance decreases and output impedance increases

    4. Input and output impedance both increase

    Answer: d

  5. The frequency of oscillation of a tunnel-collector oscillator having L = 30µH and C = 300pf is nearby

    1. 267 kHz

    2. 1677 kHz

    3. 1.68 kHz

    4. 2.67 kHz

    Answer: b

  6. The control terminal (pin 5) of 555 timer IC is normally connected to ground through a capacitor (0.01µF). This is to

    1. Protect the IC from inadvertent application of high voltage

    2. Prevent false triggering by noise coupled onto the pin

    3. Convert the trigger input to sharp pulse by differentiation

    4. Suppress any negative triggering pulse

    Answer: b

  7. The fan out of a MOS logic gate is higher than that of TTL gates because of its

    1. Low input impedance

    2. high output impedance

    3. Low output impedance

    4. High input impedance

    Answer: d

  8. The common collector amplifier is also known as

    1. Collector follower

    2. Base follower

    3. Emitter follower

    4. Source follower

    Answer: c

  9. In class-A amplifier, the output current flows for

    1. A part of the cycle or the input signal

    2. The full cycle of the input signal

    3. Half the cycle of the input signal

    4. 3/4th of the cycle of the input signal

    Answer: b

  10. In an amplifier with negative feedback

    1. Only the gain of the amplifier is affected

    2. Only the gain and bandwidth of the amplifier are affected

    3. Only the input and output impedance are affected

    4. All of the four parameters mentioned above would be affected

    Answer: d