# Boolean help required

Discussion in 'Homework Help' started by curriejohn, May 31, 2015.

1. ### curriejohn Thread Starter New Member

Feb 17, 2015
14
0
Hi

Is anyone able to help me complete the attached schematic. I have been told that the top half is correct but the bottom half is wrong.

It is asking me to complete the Boolean expression and truth table at every section where an arrow is pointing to. I would be very grateful if someone could explain this to me.

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2. ### shteii01 AAC Fanatic!

Feb 19, 2010
3,922
601
1. don't use word required. there is nothing that you can require of me.
2. you fail to present material in clear and organized manner. i am not interested in trying to puzzle out what and how of your work.

3. ### curriejohn Thread Starter New Member

Feb 17, 2015
14
0
Thanks for your incredibly helpful yet pointless comment.

4. ### bertus Administrator

Apr 5, 2008
16,974
2,962
Hello,

I have only looked at one point, but there will probably be other points also:

Bertus

5. ### curriejohn Thread Starter New Member

Feb 17, 2015
14
0

Hi Bertus

I think I was thinking along the same lines as the 1st logic gate. I think I have worked it out to be (A+D') if I'm right in saying!

6. ### gunmetol New Member

Jan 29, 2015
7
0
your expression is (A'BC+ADA') given that (')= inverted ?

all you need to do is take a second line down form after the inverter on "A" and make your two way gate into a three way one and lose the inverter on the bottom line.
redraw and post it and i will have a look.

if you don't understand why this is just ask

regards
oliver

7. ### WBahn Moderator

Mar 31, 2012
20,064
5,665
What is it you are trying to do?

1) Analyze the schematic and determine the what Boolean function it implements?

or

2) Develop a schematic that implements a desired Boolean function?

In either case, a couple of points to consider:

You have labeled the output of the final gate 'X'. Yet your truth table near the 3-input AND gate has the output labeled 'X' (and no signal name on the node connected to its output). Don't use the same name multiple places in your schematic or equations related to it -- it just causes confusion.

It can be very helpful to label all of the internal nodes and then start your expressions using those node names and expand them as needed. That makes if much easier to see your train of thought and will also greatly reduce the chance of making mistakes in the first place.