Circuit Design from Truth Table [COMPLETED]

[Lexhanatin]

Hi guys,

I'm having a bit of trouble designing my circuit.


As you can see from the picture the first 5 combinations from the truth table work, however the rest don't.

I'm still relatively new to logic circuits so any advice is greatly appreciated.

me luv u long tim <3.
P.S. Program used is logisim.

[admin]

Hi,
I suggest you do your p1 and p2 separately.
It is actually pretty easy to build circuit by truth table if you not need to do it optimally.
Just find all rows where result is 1 and construct one And element for each such row with all inputs that are 1 connected directly and all inputs that are 0 through not element.
Here is an example of such And for your first row that does not work (in the red rectangle).

Example1.Jpeg (11.16 KiB) Viewed 14000 times

Then you Or result of all Ands and you have your circuit.
Good luck with your circuit.
By the way, you can try to use LogicCircit program instead of Logisim.
Regards,
Eugene

[Lexhanatin]

Hi Eugene,
Thanks for your reply.

I've taken your advice to constructing circuits for P1 and P2 separately.
I've also constructed the rows that output 1 from the truth table.
I'm not sure why your example for the first row has the two NOT gates. It works without them.

Here screenshots for the first row and first 2 rows that output 1 (row 1, row 2, and row 7).




(I forgot to change the inputs to result in an output. They do work though).

I'm not sure what you mean by "Then you Or result of all Ands and you have your circuit."
You can't OR with a single input.
So in other word, I don't know how to combine each individual circuit.

Been super busy these past two days, only able to download the program now.

Thanks again man <3.

[admin]

It very simple you just connect outputs of all And gates to Or gate and the output of the Or gate is your result.

[Lexhanatin]

I got it working.



I just need to make it slightly neater, lol.

Thanks for your help Eugine <3.