A logic gate is a type of circuit (or collection of transistors and resistors) that regulates the flow of electricity (or optical signals in fiber optic computing systems) that determines the Boolean logic computers use to make complex logical decisions. The three simple gates-AND, OR and NOT-combine to perform complex decision making processes. The on or off state of a logic gate corresponds to the binary values.
The complex logic gates are XOR (exclusive-OR), NAND (NOT-AND), NOR (NOT-OR), and XNOR (exclusive-NOR).