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Circuit Description

This applet demonstrates an 8:1 multiplexer and the corresonding 1:8 demultiplexer.

Click the input switches or type the ('a','b','c', and 'x') bindkeys to control the demultiplexer (upper circuit), or the ('d','e','f', and '0','1', ..., '7') bindkeys to control the multiplexer.

Both circuits are basically identical, except for the different interpretation of inputs and outputs. The common connection of the single switch of the first-level relay is used as the input in the demultiplexer, but as the output of the multiplexer.

Naturally, a 2:1 multiplexer/demultiplexer would use only the first-level (single switch) relay, while a 4:1 mux/demux would use both the first-level (single-switch) and second-level (two switches) relays. The generalization to higher level should be obvious as well; for example, the 16:1 mux/demux circuits consists of four levels with an 8-switch relay. In each stage, a single relay with n switches can be replaced by multiple relays with smaller number of switches.