# Designing logic circut

Discussion in 'Electronics Homework Help' started by Nora, Apr 15, 2013.

1. ### Nora

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Jan 26, 2013
In this exercise you have to make a combinatoric digital circuit. The circuit has a bit width of 2 bit. The circuit also has two control signals A and B which decide the function of the circuit according to TABLE 1(attachement). The signals “in” and “out” are on 2's complement form.

I am completely lost on where to start here. First of all the table makes no sense to me, what does "Out = In" actually mean, and "Out = In-1" etc. perhaps that can give me some kind of clue on where to start. I read up on the basics of logic circuits and know what an AND, OR, NOT, NAND, NOR and XOR gate is, but I am not sure how all that helps me solve this exercise.

Thank you all for reading! It would be a lifesaver if anyone knew how to do this

2. ### Harald KappModeratorModerator

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Nov 17, 2011
Without the table we cannot help. Please "go advenced" and attach the table.

For starters: OUT=IN means that the output signal is identical to the input signal, so if IN=1, OUT=1 and if IN=0, OUT=0, so much should be obvious.

3. ### Nora

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Jan 26, 2013
Ok, thank you for the help, I forgot to attach the table, sorry.

I think I will do the rest on my own, you can close the thread. Also, there is really no reason to get rude over a circuit. I understand that I seem completely stupid to you, but just so you know I have fields in which I am very strong, and I have never ever told anyone who asked me for help "so much should be obvious".

4. ### Harald KappModeratorModerator

11,310
2,588
Nov 17, 2011
Sorry if I came over rude to you. I definitely didn't mean to.
What other answer would you expect to a question like

Last edited: Apr 15, 2013