Logic gates?

Question

Hi,

I have the following expressions and was wondering how I would create circuits using AND, OR, and NOT gates.

1. Y = NAND + AND
2. Y = NOT * NOT + AND
3. Y = OR * NOR
4. Y = OR * (NOT + NOT)


Thanks!

Also, do you know how the truth tables would look for the above circuits?

Thank you!

All it states is:

Y = AB (with line above both) + AB
Y = A (line above) * B (line above) + AB
Y = (A+B)(A+B) (line above)
Y = (A+B)(A (line above) + B (line above))


Thanks!

Answer 1

Take the first equation. This will always give an output of 1. You can see this by putting AB = C.
Then Y = C(bar) +C which of course is 1. The third equation will give an output of 0 whatever be the values of A and B.
The second equation is Y = A(bar)*B(bar) + A*B. Y will be 1 whenever both A & B are either 0 or 1. You can achieve this with 2 AND gates, 2 NOT gates and an OR gate.
The last equation similarly gives an output of 1 whenever A & B are dissimilar, that is one of them is 1 and the other is 0. You can get this using 2 OR gates, 2 NOT gates and an AND gate.

Answer 2

This looks like gibberish to me, you would have to draw a logic diagram for me to see what you are doing. P.S. I have been doing logic circuits for over 45 yrs.

Answer 3

I did this homework 20 years ago. Do it or you'll never get through the exam.