A logic gate is a simple electronic circuit, which operates on one or more input signals to produce standard output signals. Logic gates are the basic building blocks of all the electronic circuits in a computer. All circuits in a computer are made by the combination of logic gates. Every operation within a computer is carried out by signals passing through these logic gates. A few gates are discussed below:
There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR.
The basic operations are described below with the aid of truth tables.
The 'Exclusive-NOR' gate circuit does the opposite to the EOR gate. It will give a low output if either, but not both, of its two inputs are high. The symbol is an EXOR gate with a small circle on the output. The small circle represents inversion.
The NAND and NOR gates are called universal functions since with either one the AND and OR functions and NOT can be generated.
A function in sum of products form can be implemented using NAND gates by replacing all AND and OR gates by NAND gates.