# Implementing a boolean function using a single 8:3 decoder and a single nand gate

Discussion in 'Homework Help' started by dogadikbayir, Oct 20, 2013.

1. ### dogadikbayir Thread Starter New Member

Oct 18, 2013
12
0
ok so I am asked to implement the following boolean function: F(w,x,y) with these minterms (0,2,3,5). I am allowed to use a single decoder(74138) and a single nand gate. I found the solution using De Morgan's laws of logic but it seems like I need inverters for the minterms 0,2,3,5. Please help me...

thank you...

2. ### WBahn Moderator

Mar 31, 2012
18,087
4,917
As usual, you need to show YOUR attempt to solve YOUR homework problem. Then we can look at what you've done and where you need to go and make suggestions that will hopefully steer you down that path.

3. ### dogadikbayir Thread Starter New Member

Oct 18, 2013
12
0
ok my solution is like this: I have one 3x8 decoder with bubbles on each output and 0,2,3,5 connected together to a single NAND gate. This is right I've tested it however the task is like this: "Implement F with a single decoder and a single NAND gate".

4. ### ScottWang Moderator

Aug 23, 2012
4,933
777
The title ... using a single 8:3 decoder
But you using 74138, that is 3:8 decoder, does some mistake of the title?

5. ### WBahn Moderator

Mar 31, 2012
18,087
4,917
You have the right idea. When you say that you've tested it, how did you test it? In simulation or with the real IC? If in simulation, did you use the model for the 74138 specifically, or just a generic 3:8 decoder?

Go look at the datasheet for the 74138 and I think you'll see your problem and how to fix it.