The opposite of the multiplexer circuit, logically enough, is the demultiplexer. This circuit takes a single data input and one or more address inputs, and selects which of multiple outputs will receive the input signal. 

      Like multiplexers, demultiplexers are not limited to two data signals. If we use two addressing inputs, we can demultiplex up to four data signals. With three addressing inputs, we can demultiplex eight signals.

      Inputs A and B are the selection inputs to this demultiplexer. They select which of the four outputs, the input will be transmitted.

This circuit known as decoder/demultiplexer circuit because it can work as a decoder with enable and as a demultiplexer .In general the form of the demultiplexer is 1-to-2^n (which is opposite to the multiplexer).

The Demux used here is 1-to-4. A &B are selection lines, IN is the input data. As you can see in the truth table, the red colour indicates which output is selected.

Procedure

Move the mouse in the area at the end of the input lines to see the choice boxes.