MCQ on Digital Electronics with Answers - 6
Multiple Choice Questions with Answers on Digital Electronics Circuits - Flip-Flops
1. A basic SR flip-flop can be
constructed by cross-coupling of which basic logic gates?
a) AND or OR gates
b) XOR or XNOR gates
c) NOR or NAND gates
d) AND or NOR gates
Answer: c
2. The logic circuits whose outputs at
any instant of time depends not only on the present inputs but also on the past
outputs are called
a) Combinational circuits
b) Sequential circuits
c) Latches
d) Flip-flops
Answer: b
3. Operations of which circuits among
the following are fastest?
a) Combinational circuits
b) Sequential circuits
c) Latches
d) Flip-flops
Answer: a
4. The basic latch consists of
a) Two inverters
b) Two comparators
c) Two amplifiers
d) Two adders
Answer: a
5. In SR flip-flop, if Q = 0 the output
is said to be
a) Set
b) Reset
c) Previous state
d) Current state
Answer: b
6. What is a trigger pulse?
a) A pulse that starts a cycle of
operation
b) A pulse that reverses the cycle of
operation
c) A pulse that prevents a cycle of
operation
d) A pulse that enhances a cycle of
operation
Answer: a
7. Which of the following is correct for a gated D-type flip-flop?
a) The Q output is either SET or
RESET as soon as the D input goes HIGH or LOW
b) The output complement follows the
input when enabled
c) Only one of the inputs can be HIGH
at a time
d) The output toggles if one of the
inputs is held HIGH
Answer: a
8. The truth table of an SR flip-flop has how many valid entries?
a) 1
b) 2
c) 3
d) 4
Answer: c
9. The characteristic equation of SR latch is
a) Q(n+1) = (S + Q(n))R’
b) Q(n+1) = SR + Q(n)R
c) Q(n+1) = S’R + Q(n)R
d) Q(n+1) = S’R + Q'(n)R
Answer:
a
10. What is the disadvantage of an SR
flip-flop?
a) It has no Enable input
b) It has a RACE condition
c) It has no clock input
d) Invalid State
Answer: d
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