11-09-2017, 10:32 AM
Logical gates are the basic elements of any digital system. It is an electronic circuit that has one or more inputs and a single output. The relationship between input and output is based on a certain logic. Based on this, the logic gates are referred to as AND gate, OR gate, NO gate etc. A logic gate is an element of a digital circuit. Most logic gates have two inputs and one output. At any given time, each terminal is in one of the two low (0) or high (1) binary conditions, represented by different voltage levels. The logical state of a terminal can, and usually does, change frequently, as the circuit processes the data. On most logic gates, the low state is about zero volts (0 V), while the high state is about 5 volts positive (+5 V).
There are seven basic logical gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR.
The AND gate is called this because, if 0 is called "false" and 1 is called "true", the gate acts in the same way as the logical operator "y". The following illustration and table shows the circuit symbol and logical combinations for an AND gate. (At the symbol, the input terminals are on the left and the output terminal is on the right.) The output is "true" when both inputs are "true". Otherwise, the output is "false".
![[Image: and.gif]](http://media.techtarget.com/WhatIs/images/and.gif)
And gate
