# Logic Gates and How many types of Logic Gates in Circuits

A logic gates are basic block for digital circuits. Most of the logic gates consists of 2 inputs and one output. While in operation a logic gate terminal/point is in two binary conditions low (0) or high (1),  having different voltage levels. When a circuit starts processing data the terminal change it's state and change often. Most of the logic gates approximately have 0 volts (0 V), while the high state is approximately five volts positive (+5 V).

There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR.

AND GATE:

The AND gate is so named because, if 0 is called "false" and 1 is called "true," the gate acts in the same way as the logical "and" operator. The following illustration and table show the circuit symbol and logic combinations for an AND gate. (In the symbol, the input terminals are at left and the output terminal is at right.) The output is "true" when both inputs are "true." Otherwise, the output is "false."