Electronics mcqs

BASIC ELECTRONICS MCQs 4

BASIC ELECTRONICS MCQs 4

Q. 1 The large signal bandwidth of an opamp is limited by its

Ans: (B)

Q. 2 Rectification efficiency of a full wave rectifier without filter is nearly equal to

  • (A) 51%
  • (B) 61%
  • (C) 71%
  • (D) 81%

Ans: (D)

Efficiency of a full wave rectifier is given by [(2Im/ π) 2 x RL] / [(Im/ √2) 2 x (Rf+ RL)] = 81%, when Rg is zero.

Q. 3 When the temperature of a doped semiconductor is increased, its conductivity

  • (A) Decreases.
  • (B) Increases.
  • (C) Does not change.
  • (D) Increases or decreases depending on whether it is p- or n-type.

Ans: B

Q. 4 The main characteristics of a Darlington Amplifier are

  • (A) High input impedance, high output impedance and high current gain.
  • (B) Low input impedance, low output impedance and low voltage gain.
  • (C) High input impedance, low output impedance and high current gain.
  • (D) Low input impedance, low output impedance and high current gain.

Ans: C

Q. 5 The transconductance, gm, of a JFET is computed at constant VDS , by the following:

Ans: A

Q. 6 The feedback factor βat the frequency of oscillation of a Wien bridge oscillator is

  • (A) 3
  • (B) 1/3
  • (C) 11/29
  • (D) – 3/29

Ans: B

Q. 7 In an amplifier with negative feedback, the bandwidth is

  • (A) Increased by a factor of β
  • (B) Decreased by a factor of β
  • (C) Increased by a factor of (1+Aβ)
  • (D) Not affected at all by the feedback

Where A = gain of the basic amplifier and β= feedback factor

Ans: C

Q. 8 The 'slew rate' of an operational amplifier indicates

  • (A) How fast its output current can change
  • (B) How fast its output impedance can change
  • (C) How fast its output power can change
  • (D) How fast its output voltage can change

When a step input signal is given.

Ans: D

Q. 9 In a clamping circuit, the peak-to peak voltage of the waveform being clamped is

  • (A) Affected by the clamping
  • (B) Not affected by the clamping
  • (C) Determined by the clamping voltage value
  • (D) Determined by the ratio of rms voltage of the waveform and the clamping voltage

Ans: B

Q.10 Regulation of a.d.c. power supply is given by

  • (A) Product of no-load output voltage and full-load current
  • (B) Ratio of full-load output voltage and full-load current
  • (C) Change in output voltage from no-load to full-load
  • (D) Change in output impedance from no-load to full-load

Ans: D

Q.11 A 'literal' in Boolean Algebra means

  • (A) A variable inn its uncomplemented form only
  • (B) A variable ORed with its complement
  • (C) A variable in its complemented form only
  • (D) A variable in its complemented or uncomplemented form

Ans: D

Q.12 In an unclocked R-S flip-flop made of NOR gates, the forbidden input condition is

  • (A) R = 0, S = 0
  • (B) R = 1, S = 0
  • (C) R = 0, S = 1
  • (D) R = 1, S = 1

Ans: D

Q.13 The current amplification factor in CE configuration is

  • (A) α
  • (B) β+ 1
  • (C) 1/β
  • (D) β

Ans: D

Q.14 A zener diode

  • (A) Has a high forward voltage rating.
  • (B) Has a sharp breakdown at low reverse voltage.
  • (C) Is useful as an amplifier.
  • (D) Has a negative resistance.

Ans: B

Q.15 N-channel FETs are superior to P-channel FETs, because

  • (A) They have higher input impedance.
  • (B) They have high switching time.
  • (C) They consume less power.
  • (D) Mobility of electrons is greater than that of holes.

Ans:

Q.16 The maximum possible collector circuit efficiency of an ideal class A power amplifier is

  • (A) 15%
  • (B) 25%
  • (C) 50%
  • (D) 75%

Ans: C

Q.17 Negative feedback in an amplifier

  • (A) Reduces the voltage gain.
  • (B) Increases the voltage gain.
  • (C) Does not affect the voltage gain.
  • (D) Converts the amplifier into an oscillator.

Ans: A

Q.18 For generating 1 kHz signal, the most suitable circuit is

  • (A) Colpitts oscillator.
  • (B) Hartley oscillator.
  • (C) Tuned collector oscillator.
  • (D) Wien bridge oscillator.

Ans: D

Q.19 Phe output stage of an op-amp is usually a

  • (A) Complementary emitter follower.
  • (B) Transformer coupled class B amplifier.
  • (C ) Class A power amplifier.
  • (D) Class B amplifier.

Ans: A

Q.20 When a sinusoidal voltage wave is fed to a Schmitt trigger, the output will be

  • (A) Triangular wave.
  • (B) Asymmetric square wave.
  • (C) Rectangular wave.
  • (D) Trapezoidal wave.

Ans: B

(BASIC ELECTRONICS MCQs 4)