What gates are called universal gates?

Hint: A logic gate is a circuit which can have one or more than one input and have one single output. These devices implement Boolean functions and logical operation is performed on the binary inputs to produce one single binary output. We have many types of gates to do different operations. Universal gates are the gates which can perform the fundamental operation for each gate.

Complete step by step answer:
Logic gates are the building blocks of digital electronics. We have many logic gates as AND, OR, NOT, NAND, NOR etc.
A universal logic gate can be defined as a logic gate with the help of which we can make all the other logic gates. It can implement any Boolean function without the help of any other basic gates. We can perform the AND, OR, NOT operations without implementing these basic gates with the help of the universal gates.
We have two universal gates – NAND gate and NOR gate.
NAND gate represents the complement of AND gate. The graphic symbol for NAND gate is,

The truth table for NAND gate is



NOR gate represents the complement of OR gate. The graphic symbol for NOR gate is,

he truth table for NOR gate is,



Note: The NAND gate is the abbreviation for Not AND and the NOR gate is the abbreviation for Not OR. In digital circuits we mostly use the NANA and the NOR gate to perform the operation of all the gates because these gates are economical and easier to fabricate.