Competitive Exams: Electronics MCQs (Practice-Test 6 of 13)

  1. Which of the following amplifier is used in a digital to analog converter?

    1. non inverter

    2. voltage follower

    3. summer

    4. difference amplifier

    Answer: c

  2. Differential amplifiers are used in

    1. instrumentation amplifiers

    2. voltage followers

    3. voltage regulators

    4. buffers

    Answer: a

  3. For an ideal op-amp, which of the following is true?

    1. The differential voltage across the input terminals is zero

    2. The current into the input terminals is zero

    3. The current from output terminal is zero

    4. The output resistance is zero

    Answer: c

  4. The two input terminals of an opamp are labeled as

    1. High and low

    2. Positive and negative

    3. Inverting and non inverting

    4. Differential ans non differential

    Answer: c

  5. When a step-input is given to an op-amp integrator, the output will be

    1. a ramp.

    2. a sinusoidal wave.

    3. a rectangular wave.

    4. a triangular wave with dc bias.

    Answer: a

  6. For an op-amp having differential gain Av and common-mode gain Ac the CMRR is given by

    1. Av + Ac

    2. Av/Ac

    3. 1 + (Av/Ac)

    4. Ac/Av

    Answer: b

  7. Hysteresis is desirable in Schmitt-trigger, because

    1. energy is to be stored/discharged in parasitic capacitances.

    2. effects of temperature would be compensated.

    3. devices in the circuit should be allowed time for saturation and desaturation.

    4. it would prevent noise from causing false triggering.

    Answer: c

  8. The output voltage Vo of the above circuit is

    1. -6V

    2. -5V

    3. -1.2V

    4. -0.2V

    Answer: b

  9. In the above circuit the current ix is

    1. 0.6 A

    2. 0.5 A

    3. 0.2 A

    4. 1/12 A

    Answer: b