Sequential Circuits

Question 1

What is a latch?

Answer 1

A latch is a level-sensitive bistable device that stores one bit of data and responds to changes in input as long as the enable signal is active.

Question 2

What is a flip-flop?

Answer 2

A flip-flop is an edge-triggered bistable device that stores one bit of data and only changes state on the rising or falling edge of a clock signal.

Question 3

What is the difference between a latch and a flip-flop?

Answer 3

A latch is level-sensitive and changes output whenever enabled, while a flip-flop is edge-triggered and changes output only at the clock edge.

Question 4

How are latches and flip-flops related?

Answer 4

Flip-flops are constructed using latches and both are fundamental memory elements used in digital circuits to store binary data.

Question 5

What is the working principle of an SR flip-flop?

Answer 5

An SR flip-flop has two inputs, Set (S) and Reset (R). When S=1 and R=0, it sets output Q to 1. When S=0 and R=1, it resets Q to 0. When both S=0 and R=0, it holds the previous state. The input S=1 and R=1 is invalid.

Question 6

What is the working principle of a D flip-flop?

Answer 6

A D flip-flop samples and stores the value at its input D on the triggering clock edge. The output Q reflects the stored value and holds it until the next clock edge, effectively delaying the input by one clock cycle.

Question 7

What is the working principle of a JK flip-flop?

Answer 7

A JK flip-flop has inputs J and K. When J=0 and K=0, it holds its state. When J=0 and K=1, it resets Q to 0. When J=1 and K=0, it sets Q to 1. When J=1 and K=1, it toggles Q.

Question 8

What is the working principle of a T flip-flop?

Answer 8

A T flip-flop has one input T. When T=0, it holds its current state. When T=1, it toggles the output Q on the clock edge, switching between 0 and 1.