Editing Multiplexer (section)

==Digital demultiplexers==
{{See also|Inverse multiplexer}}
Demultiplexers take one data input and a number of selection inputs, and they have several outputs.
They forward the data input to one of the outputs depending on the values of the selection inputs.
Demultiplexers are sometimes convenient for designing general-purpose logic because if the demultiplexer's input is always true, the demultiplexer acts as a [[binary decoder]].
This means that any function of the selection bits can be constructed by logically OR-ing the correct set of outputs.

If X is the input and S is the selector, and A and B are the outputs:

<math display="block">A = ( X \wedge \neg S)</math>
<math display="block">B = ( X \wedge S)</math>

[[File:Demultiplexer Example01.svg|thumb|450px|left|Example: A Single Bit 1-to-4 Line Demultiplexer]]
{{clear}}

===List of ICs which provide demultiplexing===
[[File:ROCKY-518HV - Fairchild 74F138-2387.jpg|thumb|[[Fairchild Semiconductor|Fairchild]] 74F138 1:8 demultiplexer]]
For [[7400 series]] part numbers in the following table, "x" is the logic family.
{| class="wikitable"
|-
! IC No. (7400) !! IC No. (4000) !! Function !! Output State
|-
| 74x139
|
| Dual 1:4 demux.
| Output is inverted input
|-
| 74x156
|
| Dual 1:4 demux.
| Output is [[open collector]]
|-
| 74x138
|
| 1:8 demux.
| Output is inverted input
|-
| 74x238
|
| 1:8 demux.
|
|-
| 74x154
|
| 1:16 demux.
| Output is inverted input
|- 1:8 demux.
| 74x159
| CD4514/15
| 1:16 demux.
| Output is open collector and same as input
|}