Medium
EST. TIME: 45 minDecoder and Encoder Circuits
Realization of 2:4 Decoder and 4:2 Encoder circuit and verification of truth table.
Theory
Decoder (74139/74138): A logic circuit that converts n input lines to 2^n output lines. Used for address decoding.
Encoder (74147/74148): A circuit that converts 2^n input lines to n output lines. Used in keyboards and interrupts.
Procedure
- Decoder: Connect two inputs and enable line. Check which of the 4 outputs goes active (High/Low) based on input combination.
- Encoder: Connect 4 inputs. Only one should be active at a time. Observe the 2-bit binary code at output.