Flip-Flops

To have a sequential circuit, a storage device is required to know what has happened in the past. The basic unit of storage is the Flip-Flop.

The simplest kind of sequential circuit is a memory cell that has only two states. It can be either 1 or 0. Such two state sequential circuits are called flip-flops because they flip from one state to another and then flop back. A flip-flop is also known as bistable multivibrator, latch or toggle.

Consider the general block diagram of a flip-flop,

It has one or more inputs and two outputs Q and Q̅. The two outputs are complementary to each other. If Q=0 i.e. Reset, then Q̅=1 and
if Q=1 i.e. Set, then Q̅=0.

Types of Flip-flop
S-R flip-flop
D flip-flop
J-K flip-flop
T flip-flop

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