Logic expression with k-map or minterms-maxterms

Question

I have 4 inputs and 3 outputs.

Two of the outputs contain both 0s and 1s, so their expressions are easy to write.

However, one of the outputs has only 0s. How can I write its logic expression by using a k-map or by minterms and maxterms.

If an output is always 0, no matter what the inputs, just write out = 0, meaning connect that signal to the 0 level, with no connections to the inputs at all. — The Photon, Commented Mar 7, 2016 at 19:27
@ThePhoton we'll show them in the lab, so shouldn't i wire anything for this output? — fillhora, Commented Mar 7, 2016 at 19:30
Assuming positive logic, CMOS or TTL family, a wire connected to ground would do. — The Photon, Commented Mar 7, 2016 at 19:44

Tustique · Accepted Answer · 2016-03-07 20:36:28Z

1

If the output is always zero, regardless of what the input is, then the reduced form is very simple:

OUT=0

In the real world, this would mean that you would connect the output to the "LOW" output, which usually means ground. (0V)

answered Mar 7, 2016 at 20:36

Tustique

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fillhora · Accepted Answer · 2016-03-08 19:30:48Z

0

I learned today what should we do in this situation.

We should show any contradiction about it. For example,

Lets this output calls OUT, and one of the inputs is A. We can say simply;

OUT = A.A'

Then, OUT will be always zero.

answered Mar 8, 2016 at 19:30

fillhora

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