The Maplin Electronic Circuits Handbook, 2nd Edition

126 LOGIC CIRCUITS

the inputs is at logic 1 and the other is at logic 0. Exclusive-OR gates

produce a logic 0 output whenever both inputs have the same logical state

(i.e.

when both are at logic 0 or both are at logic 1).

Readers should note that, while inverters and buffers each have only

one input, exclusive-OR gates have two inputs and the other basic gates

(AND,

OR, NAND and NOR) are commonly available with up to eight

inputs.

Truth tables provide a handy method of illustrating the function of a

logic gate and show the state of the output of the gate resulting from all

possible input conditions. For a logic gate with η inputs, there ar