I'm designing a circuit using Logisim that I will later physically implement. Unfortunately, the gates provided to me in the physical implementation do not include one of the gates I used in my design, namely a 4-input NAND. I do, however, have access to both 2- and 3-input NANDs. Is there any way I can take the inputs to the 4-input NAND and use only 2- and 3-input NANDS to achieve the same functionality?


1 Answer 1


Do not read this answer if this is homework :-).

You get "action" only when all presented inputs are 1
1111 = 0. All other xxxx = 1
A 3 input gate will deal with 111 and give 0
But the next gate has to deal with 10
It "knows" how to deal with 11
So, invert the 0 from the 3 input gate and NAND it with the final 1

(A 2 input NAND (or 3 or 4 or ... input) knows how to be an inverter with only a little help from you. )


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.