1 bit memory cell

1 Bit Memory Cell

Introduction

If the circuit is in particular state(0 or 1),it continues to remain in that state.This property is called memory. flip flop is known as basic digital memory circuit.

• It has two stable states namely logic 1 and logic 0 state also known as set state and reset state.
• We can construct it either by using NOR gates or NAND gates.

Why is it called as '1 bit memory cell'?

Since it can store one bit of information (either Q=1 or Q=0 ),it is called as '1 bit memory cell'.

Also as the flip flop has two stable state it is also called as binary or bistable multivibrator.

Construction

• The basic digital memory circuit is designed by cross-coupling two NOR gates or NAND gates.
• The output of each gate is connected to the input of other gate.
• Such feedback combination is known as Flip Flop.

Working

• One of the most important characteristic of Flip Flop is that, its outputs are complimentary.
• Consider N1 and N2 be two NOT or NAND gates and Q & Q' be their output.
• Let output of N1 (Q) be 1.
• Therefore input of N2 becomes 1. As single input NAND or NOR is used, the output of N2 is 0.
• This output is given to the input of N1 and hence Q=1.
• This result confirms our original assumption, Q=1.
• Similarly, we can conclude that when Q=0, Q'=1 is also a possible state.
• The case in which both the outputs are same is not consistent.