Digital Logic Assignment help plz

Discussion in 'Homework Help' started by gonkar, Oct 22, 2011.

  1. gonkar

    Thread Starter New Member

    Oct 22, 2011
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    hi everybody,
    the proff. assigned us this:
    "Design a gate logic circuit to provide an output of 1 (true) when any two or more of the four inputs are 1"
    plz help me approach this X)
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
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    Sketch your attempt at a solution and then post it here.

    hgmjr
     
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  3. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    Perhaps you should start with a truth table? From there a Karnough map should be elementary.
     
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  4. gonkar

    Thread Starter New Member

    Oct 22, 2011
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  5. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    That solution will give you a 1 when any one input is true. Not the correct solution to your original problem.
     
  6. Georacer

    Moderator

    Nov 25, 2009
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    @gonkar

    Shall we insist on you giving the truth table of your function? Do you know how to build it?
     
  7. gonkar

    Thread Starter New Member

    Oct 22, 2011
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    No u don't have to insist on me doing the truth table ^^
    I'm working on that ... I'll post it when I'm done ... BRB ^___^
     
  8. MrCarlos

    Active Member

    Jan 2, 2010
    400
    134
    Hello gonkar

    Read carefuly your original statement:
    "Design a logic gate circuit to Provide an output of 1 (true) When two or more Any of the four inputs are 1"

    This statement suggests several things:
    1 - The circuit has 4 inputs.
    2 - Two of them, either, if they are 1 the output should be 1.
    3 - Naming the inputs as 1, 2, 3, 4, the possible combinations (any two) would
    1 & 2, 1 & 3, 1 & 4.
    2 & 3, 2 & 4.
    3 & 4.
    Right?

    Because:
    1, 2, 3, 4.------ Out
    0, 0, 0, 0 -------- 0
    0, 0, 0, 1 -------- 0
    0, 0, 1, 0 -------- 0
    0, 0, 1, 1 -------- 1 ----------( 3 & 4) Any Two.
    0, 1, 0, 0 -------- 0
    0, 1, 0, 1 -------- 1 ----------( 2 & 4) Any Two.
    0, 1, 1, 0 -------- 1 ----------( 2 & 3) Any Two.
    0, 1, 1, 1 -------- 1 ----------( 2 & 3) Or (2 & 4) or (3 & 4) Any Two Or More.
    1, 0, 0, 0 -------- 0
    1, 0, 0, 1 -------- 1 ----------( 1 & 4) Any Two.
    1, 0, 1, 0 -------- 1 ----------( 1 & 3) Any Two.
    1, 0, 1, 1 -------- 1 ----------( 1 & 3) Or (1 & 4) Or (3 & 4) Any Two Or More.
    1, 1, 0, 0 -------- 1 ----------( 1 & 2) Any Two.
    1, 1, 0, 1 -------- 1 ----------( 1 & 2) Or (1 & 4) Or (2 & 4) Any Two Or More.
    1, 1, 1, 0 -------- 1 ----------( 1 & 2) Or (1 & 3) Or (2 & 3) Any Two Or More.
    1, 1, 1, 1 -------- 1 ----------( 1 & 2) Or (1 & 3) Or (1 & 4) Or (2 & 3) Or (2 & 4) or (3 & 4) Any Two Or More.

    So you need 6 2-input AND gates and an OR gate with 6 Inputs.

    Greetings
    at your service
     
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  9. gonkar

    Thread Starter New Member

    Oct 22, 2011
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    thank u so much... appreciate ur help.
    I'm doing smth similar.. will post it when I'm done!
    thank u again :))
     
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