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Please helpcircuit logic problem.

  1. Sep 22, 2004 #1
    I have to make a circuit using only NAND and NOT gates to drive a 7 segment LED. My problem is that after I make the truth table and draw the karnaugh maps I of course end up with a AND/OR circuit...how exactly can I convert the AND/OR to a NAND/NAND. Also, how can I break up the 3 and 4 input AND gates to 2 input NAND gates.

    I really need help with this, I've been racking my brain trying to figure this out.

    Thanks alot!
  2. jcsd
  3. Sep 22, 2004 #2


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    Science Advisor

    Ok, think of this. Take a simple NAND truth table.

    NOT the output. You get ________

    NOT the two inputs. You get ________

    A 3 input AND can be 2 inputs into an AND with output fed into another AND along with the third input. A four input, use three ANDs. Etc.

    If you draw it out I believe its that simple.

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