# How to design a BCD to 7-segment display circuit using 4-1 multiplexors?

#### meowmeowmoo

Joined Feb 10, 2018
1
I know what the truth table looks like, and I suspect 4 4-1 mux are needed. Is the input each multiplexor getting the w0,w1,w2, and w3 and the output of each one being Y0, Y1, Y2, Y3 respectively... not really sure if I'm on the right track or how the selection signals comes into play here (the S1, S0)... How do I use the truth table to make 4-1 multiplexors... am I on the right track?

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#### WBahn

Joined Mar 31, 2012
26,398
This looks like some type of school assignment. Is it? If so, we can move it to Homework Help were it will get assistance aimed at helping you learn the concepts involved.

#### WBahn

Joined Mar 31, 2012
26,398
I know what the truth table looks like, and I suspect 4 4-1 mux are needed. Is the input each multiplexor getting the w0,w1,w2, and w3 and the output of each one being Y0, Y1, Y2, Y3 respectively... not really sure if I'm on the right track or how the selection signals comes into play here (the S1, S0)... How do I use the truth table to make 4-1 multiplexors... am I on the right track?
You say that you suspect four muxes are needed. But then you say the output of each being Y0... and you have second Yn signals. How does that work out.

First off, are you sure you understand what a 4-1 mux is? How many inputs and outputs does one have and how do they control the behavior.

#### AnalogKid

Joined Aug 1, 2013
9,487
Using nothing but 4:1 multiplexers, I think it would take a minimum of 21 devices. Plus other gating logic.

ak