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9.7: Multiplexers

  • Page ID
    1963
  • [ "article:topic", "authorname:tkuphaldt", "license:gnu" ]

    A multiplexer, abbreviated mux, is a device that has multiple inputs and one output. The schematic symbol for multiplexers is

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    The truth table for a 2-to-1 multiplexer is

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    Using a 1-to-2 decoder as part of the circuit, we can express this circuit easily.

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    Multiplexers can also be expanded with the same naming conventions as demultiplexers. A 4-to-1 multiplexer circuit is

    04472.png

    That is the formal definition of a multiplexer. Informally, there is a lot of confusion. Both demultiplexers and multiplexers have similar names, abbreviations, schematic symbols and circuits, so confusion is easy. The term multiplexer, and the abbreviation mux, are often used to also mean a demultiplexer, or a multiplexer and a demultiplexer working together. So when you hear about a multiplexer, it may mean something quite different.