Circuit for performing addition and subtraction

Discussion in 'General Electronics Chat' started by workingman, Aug 11, 2004.

  1. workingman

    Thread Starter New Member

    Jul 11, 2004
    2
    0

    Hi,
    Iam trying a circuit that performs addition and subtraction on two single digit numbers given as inputs. Iam at a cross -please help.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Can you post the schematic? There's a number of ways to build adders and/or subtractors. We have to know your circuit before being able to advise.
     
  3. haditya

    Senior Member

    Jan 19, 2004
    220
    0
    voltage adder/subtractors can be built using opamps... do u want to build "analog" voltage adders or "logic" adder subtractors
     
  4. workingman

    Thread Starter New Member

    Jul 11, 2004
    2
    0
    I want to build a logical circit that performs addition and subtraction on two single digit numbers given as input. I shall soon try to send a block diagram of it.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Does your project require reinventing the wheel, or can you use logic ic's?. A 74LS83, for instance, is a four bit full adder with carry. To do a subtraction, compliment the number to subtract, and add it to the other number.

    If you get the manual for LS TTL logic, you also get the internal logic of the chip, which describes how to build the function using AND/NAND & OR/NOR gates. If they're still using MIL-STD 806C logic symbology, that is.
     
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