Hi everyone-

I am working on this problem for homework:

a) Design the 8-input NAND gate using 2-input NAND gates and NOT gates.

b) Design the 8-input NAND gate using 2-input NAND gates, 2-input NOR gates ,and NOT gates only if needed.

c) Compare the number of gates used in (a) and (b).

My attempt at a solution:

part a) I simply drew a NAND gate with four inputs and then connected a two input NAND gate to each of the four inputs. As far as variables go, I just assigned letters A-H as my imputs. Is this correct?

part b) I am not really sure what to do here. Pointers please?

part c) Obviously I need to complete part A and B before I can do this.

Thanks in advance for your help everyone!

 

Are you confused about what the questions are asking or about the electronics/logic involved?

I ask that, because I don't see why you chose to use a 4-input NAND gate for the first question. The question seems to be specific about only using 2-input NAND gates.

John

 

Are you familiar with Boolean logic and working with its epxressions? You basically have to rework the expressions to get the operations that are available.

I 'll give you an expample on how to do it, by constructing a 4-input NAND with method a). Let the inputs be A1 to A4. I have available expressions of \(\bar {A \cdot B}\) and \(\bar{A}\).

I start from the outcome I want:
\(F=\bar{A1A2A3A4}\\
=\bar{(A1A2)(A3A4)}\\
=\bar{\bar{\bar{(A1A2)}} \cdot \bar{\bar{(A3A4)}}\)

Now try it yourself!