Multiplexer (Selector)

A selection line, selects which of the inputs are output.

Can be used to simplify large truthtables.

2-to-1 MUX

Simplification of cirtuits

Digital Multiplexer

The input is never directly connected to the output, but is derived from the input.

Analog Multiplexer

The input is connected directly connected to the output is enabled.

This can be implemented with tri-state buffers like on this slide.