Flip Flops

Flip Flops:

·         A Flip Flop is a memory element that is capable of storing one bit of information.

·         It is also called as Bistable Multivibrator since it has two stable states either 0 or 1.

 There are following 4 basic types of flip flops-

1.    SR Flip Flop

2.    JK Flip Flop

3.    D Flip Flop

4.    T Flip Flop

SR Flip Flop-

·         SR flip flop is the simplest type of flip flops.

·         It stands for Set Reset flip flop.

·         It is a clocked flip flop.

Construction of SR Flip Flop-

There are following two methods for constructing a SR flip flop-

 

1.    By using NOR latch

2.    By using NAND latch

1. Construction of SR Flip Flop By Using NOR Latch-

This method of constructing SR Flip Flop uses-

·         NOR latch

·         Two AND gates

Logic Circuit-

The logic circuit for SR Flip Flop constructed using NOR latch is as shown below-

2. Construction of SR Flip Flop By Using NAND Latch-

This method of constructing SR Flip Flop uses-

·         NAND latch

·         Two NAND gates

Logic Circuit-

The logic circuit for SR Flip Flop constructed using NAND latch is as shown below-

Logic Symbol-

The logic symbol for SR Flip Flop is as shown below-

Truth Table-

The truth table for SR Flip Flop is as shown below-

The above truth table may be reduced as-

Characteristic Equation-

Draw a k map using the above truth table-

From here-

Q_n+1 = ( SR + SR’ ) ( Q_n +  Q’_n ) + Q_n ( S’R’ + SR’ )

Excitation Table-