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Homework Help: Logic Circuits

  1. Apr 24, 2015 #1
    1. The problem statement, all variables and given/known data

    The questions is as follows: For each circuit write the equivalent logic expression.
    2. Relevant equations

    (B' + C) * A (?) My Attempt at circuit 2
    (A* (A' * C') * B') + (A * C * B) My Attempt at Circuit 1

    3. The attempt at a solution

    I attempted circuit 2 and circuit 1 but circuit 2 is easier because i think i know some of the basics but circuit 1 was very complicated (I did look at it and try to work it out, my best guess really) and i really need an assist on that as for circuit 2 here is what I got and my reasoning: (B' + C) * A

    In the second circuit you have three gates. A "NOT" gate, a "OR" gate and an "AND" gate.

    1) "NOT" gates inverts the input. An input of '1' for a NOT gate would result in a '0' and an input of '0' would result in a '1'. So if the input is say x we denote the output by x′ where x′ denote the opposite of x. So B becomes B'.

    2) "OR" gates take two inputs and add then together. Basically this means if the two inputs are x and y the output will be x+y. So B' becomes B'+C

    3) "AND" gates take two inputs and multiplies then together. Hence if the two inputs are x and y the output will be xy. So B' + C becomes (B'+C) * A
    Last edited: Apr 25, 2015
  2. jcsd
  3. Apr 25, 2015 #2
    Yes, that is correct. Have you made an attempt for circuit 1?
  4. Apr 25, 2015 #3
    I found it very hard. I know what the gates mean but all those pathways going everywhere is just to confusing. BUT if i had to guess I would say something like: (A* (A' * C') * B') + (A * C * B).
    Last edited: Apr 25, 2015
  5. Apr 25, 2015 #4
    Just start from the right side, and work backwards slowly. Take your time.
  6. Apr 25, 2015 #5
    Am I close? (A* (A' * C ') * B ') + (A * C * B)
  7. Apr 25, 2015 #6
    I also came up with some tables is this right?

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  8. Apr 25, 2015 #7
    I think i mucked up circuit 1: its (A* (A' * C ')' * B ') + (A * C * B). Could someone tell me if i'm right?


    Attached Files:

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  9. Apr 25, 2015 #8
    Yes, that looks correct.
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