Electronics Engineering And Circuit Design

The buffer Gate and some basic circuit design

The Buffer:

The first basic gate is a buffer. Output is the same as the input.

Learning Objectives:

Introducing buffer implementation using

Switches
Diodes

The logic symbol is the same as that of a NOT gate except the bubble.

Logical Expression:

A = Y

The Buffer
Input A	Output Y
0	0
1	1

Logical Buffer (Explain with the help of switches)

The switch model

In practical life, we never use a switch as a buffer. The purpose of a switch model is to explain easily. Just like a switch, its purpose is to transfer the input to the output. There are so many different ways to implement the buffer logic. We will limit our study to a very basic buffer circuit.

In digital circuit design, there are various ways to implement the buffer.

Two inverters in series can act as a buffer:

Simple and easy task. Two inverters in series will produce the same logic as that of input. In this way the input inverses two times and the output is the same as that of the input.

Buffer with the help of an AND gate:

Consider a two-input AND gate. Connect both of its input terminals. It works as a buffer. Have a look at the schematic diagram.

Buffer with the help of an OR gate:

Consider a two-input OR gate. Connect both of its terminals. It will act as a buffer.

Note: there is a difference between input wave and output wave amplitude. This is because every practical circuit experiences a voltage drop. The drop is due to the internal circuitry of the logic gates.