Digital Electronics MCQs

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In a JK master slave flip flop

  • A. master is clocked when clock is low
  • B. slave is clocked when clock is high
  • C. master is clocked when clock is high and slave is clocked when clock is low
  • D. master is clocked when clock is low and slave is clocked when clock is high
  • Correct Answer: Option C

Which of the following is susceptible to race condition?

  • A. R-S latch
  • B. D latch
  • C. Both R - S and D latches
  • D. None of the above
  • Correct Answer: Option A

In a positive edge triggered JK flip flop

  • A. High J and High K produce inactive state
  • B. Low J and High K produce inactive state
  • C. Low J and Low K produce inactive state
  • D. High J and Low K produce inactive state
  • Correct Answer: Option C

In a positive edge triggered D flip flop

  • A. D input is called direct set
  • B. Preset is called direct reset
  • C. Present and clear are called direct set and reset respectively
  • D. D input overrides other inputs
  • Correct Answer: Option C

A 3 input NAND gate is to be used as inverter. Which of the following will give better results?

  • A. The two unused inputs are left open
  • B. The two unused inputs are connected to 0
  • C. The two unused inputs are connected to 1
  • D. None of the above
  • Correct Answer: Option C

Assertion (A): A multiplexer can be used for data routing. Reason (R): A multiplexer has one input and many outputs.

  • A. Both A and R are correct and R is correct explanation of A
  • B. Both A and R are correct but R is not correct explanation of A
  • C. A is true, R is false
  • D. A is false, R is true
  • Correct Answer: Option C

If memory chip size is 256 x 1 bits, the number of chips required to make 1 k byte memory is

  • A. 8
  • B. 12
  • C. 24
  • D. 32
  • Correct Answer: Option D

DeMorgan’s first theorem shows the equivalence of

  • A. OR gate and Exclusive OR gate
  • B. NOR gate and Bubbled AND gate
  • C. NOR gate and NAND gate
  • D. NAND gate and NOT gate
  • Correct Answer: Option B

Using the same flip flops

  • A. a synchronous flip flop can operate at higher frequency than ripple counter
  • B. a ripple counter can operate at higher frequency than synchronous counter
  • C. both ripple and synchronous counter can operate at the same frequency
  • D. can not determine
  • Correct Answer: Option A

A current tracer responds to

  • A. steady current only
  • B. pulsating current only
  • C. both pulsating and steady current
  • D. none of the above
  • Correct Answer: Option B