Solution:

1] Encoder: It is combinational ckt which is designed to perform the inverse operation of decoder..

• An encoder has ‘n’ number of i/ps and ‘m’ number of o/ps.

• An encoder produces an m- bit binary code corresponding to digital i/p number.

Types of encoders:

1] Priority encoders.

2] Decimal to BCD encoder.

3] Octal to binary encoder.

4] Hexadecimal to binary encoder.

2] Decoder:

• Decoder is identical to DEMUX except data i/p.

• It performs operation exactly opposite to encoder.

Application:

1] Code converter.

2] Relay sub tractor.

3] BCP to 7-seg decoder.

4] Nixie tube decoder.

5] Chip selection logic ckt.

Example 2:4 decoder.

Truth table:

Logic gate diagrams:

NOTE: In decoder only one o/p is active at a time.