Full Adder using MUX

Discussion in 'Homework Help' started by Justine1, Jul 26, 2010.

  1. Justine1

    Thread Starter New Member

    Jul 26, 2010
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    How to implement a Full Adder Circuit using a 2:1 MUX?
     
  2. JDT

    Well-Known Member

    Feb 12, 2009
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    85
    Start by drawing a Truth Table for your Full adder.

    A full adder has three inputs: A and B and Carry-in. Two outputs: Sum and Carry-out.

    This cannot be implemented with only one 2:1 multiplexer. A number will be required. So not sure about "a" in your question.
     
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  3. Justine1

    Thread Starter New Member

    Jul 26, 2010
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    How can I implement A Full Adder using a 4:1 MUX?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    Per post #2, draw up a truth table. Think about a multiplexer and how to make the output agree with the truth table. A full adder requires a carry bit - can a MUX do that by itself?
     
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  5. Justine1

    Thread Starter New Member

    Jul 26, 2010
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    Can anyone please tell me how to implement a full Adder circuit using two 2:1 MUX?...:(
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    This is a stone wall project for students.

    Build up to it with a half adder. make the truth table using A & B as the two bits, X as the output. Look at a MUX and see if you can't get A & B to select the X value in the truth table for the multiplexer's output.

    Do this, and all else becomes clear.
     
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