Realization of Logic Circuit using Universal Gates

REALIZATION OF LOGIC CIRCUITS USING UNIVERSAL GATES

AIM:

To realize AND, OR, NOT and XOR functions using NAND and NOR gates and verify the truth table.

MATERIALS AND TOOLS REQUIRED:

Digital trainer kit, IC7400, 7402.

THEORY:

NAND and NOR gates are known as universal gates because any basic logic gates or Boolean expression can be realized using either NAND gates or NOR gates alone.

NAND operation: NAND is the complement of AND .If the two inputs are A&B, output Y is A.B. When both the inputs are low, the output A.B is 1. If any one of the inputs is low, still output is 1.If both the inputs are high then output is 0.Thus the NAND operation produces a logic high output if any of the input is low. It produces a low output if all the inputs are high.

NOR operation: NOR is the complement of OR .If the two inputs are A and B, output Y is A+B. When both the inputs are low, the output A+B is 1. If any one of the inputs is high, output is 0.If both the inputs are high then, still output is 0.Thus the NOR gate produces a logic low output if any of the inputs is high. It produces a high output if all the inputs are low.

Circuit Diagram:

PROCEDURE:

Check all the components and IC packages using multi meter and digital IC tester. Set up the circuits on the breadboard of the trainer kit. Apply logic levels at the inputs and observe the outputs. Verify the truth tables.

RESULT:

AND, OR, NOT and XOR functions were realized using NAND&NOR gates and verified the truth tables