# Hello People I need some help with 2 bit comporator

#### tetova

Joined May 30, 2012
5
Hi to everyone I would apperciave everyones help, I have an project in Fundamental of logic design, I've done all of it expect the EXPERIMENTAL BOARD with series number can anyone tell me how to do it ?

Best Regards.

#### tetova

Joined May 30, 2012
5
any solution ?

#### crutschow

Joined Mar 14, 2008
27,475
Have no idea what the EXPERIMENTAL BOARD is.

#### tetova

Joined May 30, 2012
5
This is the one I did

Now I have to design it like this but I have no Idea how to do it, if you can do it for I would apperciate it very much couse its very urgently

#### MrChips

Joined Oct 2, 2009
23,963
Just remember that no one is going to do your homework for you.
If you have a problem or a question maybe someone will try to help.

#### tetova

Joined May 30, 2012
5
Dear MrChips am not asking to do my homework am asking help for this thing .
If you can help I would apperciate couse this asnwer didn't help me at all :]

#### MrChips

Joined Oct 2, 2009
23,963
Well then what is your question?

#### WBahn

Joined Mar 31, 2012
26,398
Q1) What is the truth table for what you WANT to have happen?

Q2) What is the truth table for what IS happening?

Q3) Which of the three outputs is not behaving properly?

#### WBahn

Joined Mar 31, 2012
26,398
Dear MrChips am not asking to do my homework am asking help for this thing .
If you can help I would apperciate couse this asnwer didn't help me at all :]

Now I have to design it like this but I have no Idea how to do it, if you can do it for I would apperciate it very much couse its very urgently

#### absf

Joined Dec 29, 2010
1,949
First you have to change U1 U2 and U3 to something easier for u to understand.

Let's assume the 3 inputs of U1 are A, B and C and the output is (A>B).

(A>B) = A' + B' +C' = (A.B.C)' So U1 & U2 are actually 3-input NAND gates.
Applying the same method, U3 is 2-input NOR gate.

Then you can google for TTL inverter, TTL 2-input NOR. TTL 2-input NAND and TTL 3-input NAND gates. Get the chip numbers and and their datasheets. Put the pin # onto your schematic as well as the part numbers. Then you can start connecting your Experiment Board...

HTH

Allen

#### Attachments

• 34.4 KB Views: 23

#### tetova

Joined May 30, 2012
5
First you have to change U1 U2 and U3 to something easier for u to understand.

Let's assume the 3 inputs of U1 are A, B and C and the output is (A>B).

(A>B) = A' + B' +C' = (A.B.C)' So U1 & U2 are actually 3-input NAND gates.
Applying the same method, U3 is 2-input NOR gate.

Then you can google for TTL inverter, TTL 2-input NOR. TTL 2-input NAND and TTL 3-input NAND gates. Get the chip numbers and and their datasheets. Put the pin # onto your schematic as well as the part numbers. Then you can start connecting your Experiment Board...

HTH

Allen
This helped me a lot thank you very much

And you others thanks for waisting my time

#### MrChips

Joined Oct 2, 2009
23,963
You're very welcome. Please don't come again.