# Homework Help: NAND Logic 4 input circuit with nonstandard output

1. Nov 25, 2012

### YAHA

1. The problem statement, all variables and given/known data

I have a weird boolean algebra expression for which I need to build a circuit using solely the NAND gates. There are 4 inputs A,B,C,D. From the truth table (I do not know how else to approach this question other than constructing the truth table and then trying to fit the output by playing around with gates) it seems that the output is zero unless C and D are both 1's or A and B are both 1's or more than two variables are 1's

2. Relevant equations

3. The attempt at a solution

Built the truth table. Aside from looking for tips to solve this, I am also looking to find out if there is some general method or rule of approaching these things.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Nov 26, 2012

### aralbrec

We don't see any truth table or expression.

3. Nov 26, 2012

### Staff: Mentor

Post the expression.