Encoder
A combinational circuit that performs a reverse operation on a decoder is known as an encoder. It has a maximum of 2^N input lines and ‘N’ output lines and will produce a binary code equivalent to the input, which is active High.
There are various types of encoders, some of them are mentioned below:
4 to 2 Encoder
It has 4 inputs and 2 outputs.
Truth Table:
| Inputs | Outputs | ||||
| Y3 | Y2 | Y1 | Y0 | A1 | A0 |
| 0 | 0 | 0 | 1 | 0 | 0 |
| 0 | 0 | 1 | 0 | 0 | 1 |
| 0 | 1 | 0 | 0 | 1 | 0 |
| 1 | 0 | 0 | 0 | 1 | 1 |
Boolean Function:
A1=Y3+Y2
A0=Y3+Y1
Reference