1. The problem statement, all variables and given/known data I'm trying to implement the function F = A'BC+ABD+AB'D' using 3 tri-state buffers. Apparently I'm supposed to connect the buffers together and use C, D, and D' as inputs to buffers. I'm supposed to pass A and B through logic to get the input signals. I'm supposed to additional logic. 2. Relevant equations 3. The attempt at a solution Since I'm not given any other restrictions I made the following circuit http://imageshack.com/a/img703/7883/np43.png [Broken] This gives me the correct truth table for the function except for 0000 0001 0010 0011 0100 I get Z, otherwise for all of the other input combinations I get the same outputs as the function. I'm not exactly sure if I'm doing something wrong or need to change somethings around but I'm seem to be stuck. Thanks for any help.