Flip Flops – 1 MCQ’s

Digital Circuits Electronics & Communication Engineering

This set of Digital Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Flip Flops – 1″.

1. One example of the use of an S-R flip-flop is as ___________
a) Transition pulse generator
b) Racer
c) Switch debouncer
d) Astable oscillator

2. The truth table for an S-R flip-flop has how many VALID entries?
a) 1
b) 2
c) 3
d) 4

3. Latches constructed with NOR and NAND gates tend to remain in the latched condition due to which configuration feature?
a) Low input voltages
b) Synchronous operation
c) Gate impedance
d) Cross coupling

4. When both inputs of a J-K flip-flop cycle, the output will ___________
a) Be invalid
b) Change
c) Not change
d) Toggle

5. A basic S-R 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

6. Whose operations are more faster among the following?
a) Combinational circuits
b) Sequential circuits
c) Latches
d) Flip-flops

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

8. The logic circuits whose outputs at any instant of time depends only on the present input but also on the past outputs are called ________________
a) Combinational circuits
b) Sequential circuits
c) Latches
d) Flip-flops

9. How many types of sequential circuits are?
a) 2
b) 3
c) 4
d) 5

10. The basic latch consists of ___________
a) Two inverters
b) Two comparators
c) Two amplifiers
d) Two adders

11. The output of latches will remain in set/reset untill ___________
a) The trigger pulse is given to change the state
b) Any pulse given to go into previous state
c) They don’t get any pulse more
d) The pulse is edge-triggered

12. The sequential circuit is also called ___________
a) Flip-flop
b) Latch
c) Strobe
d) Adder

13. The circuits of NOR based S-R latch classified as asynchronous sequential circuits, why?
a) Because of inverted outputs
b) Because of triggering functionality
c) Because of cross-coupled connection
d) Because of inverted outputs & triggering functionality

14. In S-R flip-flop, if Q = 0 the output is said to be ___________
a) Set
b) Reset
c) Previous state
d) Current state

15. 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

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