Implementation using simple logic gates

OR, AND and NOR gates are the simple logic gates as they together can be used to construct the logic circuit for any given logic or boolean expression. The NAND and NOR gates have a special property that these gates can individually be used to construct logic circuit for any boolean expression. That is, it is possible to use either only the NAND gates or only the NOR gates to implement any boolean expression. It is so because a combination of NAND gates or a combination of NOR gates can be used to perform the function of any of the basic logic gates. It is because of this reason that NAND and NOR gates are called universal gates.

Implementation of Universal Gates:

1. AND gate using NAND gates

 
2. OR gate Using NAND Gates

 
3. OR gate Using NOR Gates

 
4. AND gate Using NOR Gates