# Home work help!!!

#### r1man01

Joined Feb 6, 2012
3
I need help desinging this circuit on paper so that I can build it in multisim and on a bread board for my digital circuit class. Please let me know if you can help out. I have attached a description of my circuit that i have to build for my lab home work.

Thanks!

kris

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#### Georacer

Joined Nov 25, 2009
5,182
Okay, you have provided enough info for your problem, but we will need to see an effort towards the solution from your part, before we begin to help you.

Post any work you have done so far.

#### r1man01

Joined Feb 6, 2012
3
Okay, you have provided enough info for your problem, but we will need to see an effort towards the solution from your part, before we begin to help you.

Post any work you have done so far.

If I new how to build the circuit I wouldn't be asking for help or posting on this website. I'm still trying to figure the problem out as we speak.

#### Georacer

Joined Nov 25, 2009
5,182
Okay, let's start from the first question.

Can you implement a circuit that will "recognize" the number 5 (binary 0101), using logic gates, and output a HIGH (1) in that case?

I think it's pretty basic.

#### BillO

Joined Nov 24, 2008
990
Here is a hint.

(LSB to the right)

Since 5 = 0101
and 9 =1001

They both have two high bits and two low bits. Exactly the same circuit will work for both, you just have to re-arrange the inputs.

#### r1man01

Joined Feb 6, 2012
3
Thanks, i'n trying to get it to work in multisim. Thanks for the hint

#### BillO

Joined Nov 24, 2008
990
Good,

If you can't get it to work, post what you tried and we'll help.

#### BillO

Joined Nov 24, 2008
990
I guess you got it to work?

With 5=0101 (DCBA)

Did you get A and C and not( B or D)?

Implement with a 3 input AND gate, and a NOR gate.

For 9, swap D and C.