Abstract


  • Short form Mux, also known as data selector
  • A multiplexer is a Combination Circuit that selects one of several input signals and forwards the selected input into a single line. It uses selection lines(control signals) to choose which input to send to the output

General example

An 8-to-1 multiplexer has 8 input lines, 3 selection lines (to choose between the 8 inputs), and 1 output line. Depending on the combination of the selection lines, one of the 8 inputs is connected to the output.

Important

We can look at the input lines as minterms, and the circuit can be implemented in 2 ways as shown above.

De-multiplexer

  • Short form Demux
  • A demultiplexer is the reverse of a Multiplexer. It takes a single input and channels it to one of several output lines, determined by the selection lines(control signals)

General example

A 1-to-4 demultiplexer has 1 input line, 2 selection lines (to choose between the 4 outputs), and 4 output lines. The input signal is routed to one of the 4 output lines based on the selection line combination.

Important

Demux has the same circuit as a decoder with enable, where the enable is the data and the inputs to be decoded are the control signals.