Question

What is main logic gates? How many types are they? Draw their symbols and Truth Table.

Answer 1

Main Logic Gates: A digital circuit which either allows a signal to pass through or stop it, is called a gate.
Mainly logic gate are of three types. OR, AND & NOT gate.
(i) OR Gate:
Truth Table:

Input		Output
$A$ $0$ $0$ $1$ $1$	$B$ $0$ $1$ $0$ $1$	$Y=A+B$ $0$ $1$ $1$ $1$

(ii) AND Gate:
Truth Table:

Input		Output
$A$ $0$ $0$ $1$ $1$	$B$ $0$ $1$ $0$ $1$	$Y=A\cdot B$ $0$ $0$ $0$ $1$

(iii) NOT Gate:
Truth Table:

Input $A$	Output $Y=\overline{A}$
$0$ $1$	$1$ $0$