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Date: 9 Apr 2013

William Eccles and F.W. Jordan invented the flip-flop from vacuum tubes in 1918. So it was
initially called Eccles-Jordan trigger circuits. The name flip-flop comes may be because of the circuit’s ability to flip from one state to another and back again.

What is Flip-Flop?

Flip-Flop is a sequential circuit that keeps on retaining the binary state until directed by an input signal to change the states. It is a basic unit for storage as it retains the stored information for usage.

flip flop symbol


A flip-flop is a bistable electronic circuit. It has two stable states: output is either to 0V (logic 0) or +5V dc (logic 1). Flip-Flop is called 1-bit memory unit as it stores only 1-bit information.

A flip-flop is represented by a rectangle with inputs on the left and outputs on the right. One input indicates the normal state and the other output with small-circle indicates the complement output.

Flip-flop is edge triggered. It retains the bit by using the concept known as feedback. That is the output of a circuit is fed back as an input to the same circuit. Basically a flip-flop is a memory element or a storage capable of storing one bit of information.


  1. 4 Comments to “Flip-Flops”

    1. […] ALU contains number of flip-flops called flags to store information related to the result of the operation. The information may be […]

    2. […] RAMs are using flip-flop like cells which can store data as long as the power supply remains on. Both reading and writing […]

    3. […] the output of a flip flop is used as the clock input for the next flip flop, the counter is called ripple counter or asynchronous […]

    4. […] basic idea is to keep the J and K inputs of each flip flop high, such that the flip flop will toggle with any negative clock […]