I am trying to learn DEMUX.
So, I have a 4 Channel DeMUX Diagram:
From this diagram we can clearly see that a DEMUX needs 2 Select Lines and 1 Input to give 4 output lines.
After that I have taken a look at the datasheet of 1:4 DeMUX IC 74LS139, which describes a diagram as shown below. Here is the link to take a look at datasheet.
In second image we can clearly see that it has two input lines A0a and A1a on left DeMUX and A0b and A1b on right DeMUX. There is no select lines. Also we cannot see a logical connection between any input lines of Left and Right DeMUX.
Can someone explain me, how to use this IC as DeMUX?