How to replace 8:1 multiplexer with two 4:1 multiplexers, having three selection lines(three variables)..?

Question

How to replace 8:1 multiplexer with two 4:1 multiplexers, having three selection lines(three variables)..?

Answer 1

make one variables = scredriver.

Then use the screwdriver to remove the 8:1 multiplexer, and then secure the fresh new 4:1 multiplexers in place.

after that, make second variable = book of electronics nad go and read it

then make 3rd variable = chair, sit on in and finish your homework ...

Answer 2

If your 4:1 multiplexers have a disable, you can do this.. if not, you basically need another 2:1 multiplexer to multiplex the outputs of the two 4:1 multiplexers.

Assume your control word is composed of the bits ABC. Run AB to both of the 4:1 multiplexers, then run C to the active high enable of one and the active low enable of the other, then tie the outputs together (well, ideally.. in TTL logic you would need high-Z or open collector outputs for this). Without the enables, you would use the C bit to select between the two 4:1 multiplexers.