Universal gates

NAND and NOR logic gates are also known as universal gates . Any combinational and sequential logic can be implemented using NAND and NOR gates. Even the flip flop circuits are constructed using universal gates.

NAND

The equivalent operations of NOT, AND and OR gates using NAND gates are shown below

NOT using NAND

NAND as NOT

AND using NAND

NAND as AND

OR using NAND

NAND as OR

NOR

The equivalent operations of NOT, OR and AND gates using NOR gates are shown below

NOT using NOR

NOR as NOT

OR using NOR

NOR as OR

AND using NOR

NOR as AND