Logic gates are those physical devices which perform a logical operation. The logical operation also called switching operation. In a digital system, some basic operations performed which are simple and easier in the calculation. These operations may be required to be performed a number of times in a large digital system like a digital computer.
Electronics circuit which done the logical decisions and the process is called as logic gates. Each gate has one or more input and only one output. Some basic gates are OR, AND and NOT gates. NAND, NOR, and EX-OR are known as universal gates.
Basic gates are-
Any Boolean expression can be realized by using the AND, OR and NOT gates discussed previously. From these three operations, two more operations have been derived: the NAND operation and NOR operation. These operations have become very popular and are widely used, the reason being the only one type of gates, either NAND or NOR are sufficient for the realization of any logical expression. Because of this reason NAND and NOR gates are known as universal gates.