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Logic Gates

  1. Apr 13, 2009 #1
    1. The problem statement, all variables and given/known data

    I'm studying logic gates and trying to create my first one.

    2. Relevant equations

    3. In a TV programme, the panel votes on new performers.
    The panel consists of a Chairman (C) and three others (X, Y and Z) who each press a button to register their vote.

    The SUCCESS light is switched on if:
    Either The Chairman and at least one of the panellists vote yes
    Or All three panellists vote yes

    Otherwise the FAIL light is switched on.

    Design a logic circuit which correctly switches each light on according to the voting of the panel.

    3. The attempt at a solution

    I've written all the statements our and managed to derive:

    S = C AND (X OR Y OR Z) OR (X AND Y AND Z)

    Which I think is correct. I'm now not sure where to go from here. I've googled but cant find any think relevant.

    Last edited: Apr 13, 2009
  2. jcsd
  3. Apr 13, 2009 #2


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    Homework Helper

    I think you will want to be clear with your grouping.

    S = (C Λ (X V Y V Z)) V ( X Λ Y Λ Z)
  4. Apr 13, 2009 #3
    Ah yes, that looks better.

    Whats my next step? Do I need to input it into a truth table or do I go streight to the logic gates? Also, can and AND statement have more than 2 inputs?

  5. Apr 13, 2009 #4


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    Homework Helper

    Sure you can put as many inputs into an And or Or or Nand or Nor as you want.

    Unless you are asked for a Truth Table ... why bother?
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