4 bit binary adder

Discussion in 'General Electronics Chat' started by Kaiser Ed Bayawa, Feb 12, 2016.

  1. Kaiser Ed Bayawa

    Thread Starter Member

    Mar 19, 2015
    60
    6
    does anyone here already made a circuit called binary adder
    i have here: 74ls83 and 74ls86 ic and a logic gate about the circuit.
    my problem is i dont know how to make it work. i already have researched its data sheets to determine the correct pins but still not working.
     
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  2. hp1729

    Well-Known Member

    Nov 23, 2015
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    The schematic you have looks like a good start. What part doesn't work? All you need is switches for inputs and LEDs for outputs.
    Something like this ... I like your addition of the 7486.
     
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  3. Kaiser Ed Bayawa

    Thread Starter Member

    Mar 19, 2015
    60
    6
    when I input 0001 and 0001 to 83 and 86 any output wont light up sir
     
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  4. absf

    Senior Member

    Dec 29, 2010
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    372
    Referring to circuit in post #1.

    Did you connect "SEL" to Ground?

    Allen
     
  5. absf

    Senior Member

    Dec 29, 2010
    1,493
    372
    Referring to circuit in post #1.

    Did you connect "SEL" to Ground?

    4 bit adder.PNG
    Allen
     
    Last edited: Feb 12, 2016
  6. hp1729

    Well-Known Member

    Nov 23, 2015
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    I have to ask ... power and ground to the 7483? Pin 5 and 12 is it?
     
  7. Kaiser Ed Bayawa

    Thread Starter Member

    Mar 19, 2015
    60
    6
    no sir i thought sed would be connected to the source.. should i put some resistors to the pins for safety?
     
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  8. absf

    Senior Member

    Dec 29, 2010
    1,493
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    Yes, Vcc=5 and Gnd=12.
     
  9. absf

    Senior Member

    Dec 29, 2010
    1,493
    372
    No, all pins connected to SEL are inputs. You can make it either High or Low. No resistor needed unless you insist.
    C1 is carry-in and C5 is carry-out (as in your diagram), of the adder.

    Allen
     
  10. Kaiser Ed Bayawa

    Thread Starter Member

    Mar 19, 2015
    60
    6
    sir what do you mean by vcc=5 and ground=12 should i use 2 sources? the 5 volts and the 12volts?
     
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  11. hp1729

    Well-Known Member

    Nov 23, 2015
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    No, he is saying ground is pin 12. All your schematic shows looks good so your problem must be something not shown on the schematic. It just didn't show power pins. What are you using for inputs and outputs?
     
  12. absf

    Senior Member

    Dec 29, 2010
    1,493
    372
    What "source"? Do you mean +5V or logic High?

    I think 'SEL' is making the B inputs of the adder negative. When 'SEL' is high, the XOR gates would complement the B inputs. Thus 0001 would become 1110 with C1 set high. So 0001 + 1110 + carry in becomes 0000 with carry out =1.

    Allen
     
  13. hp1729

    Well-Known Member

    Nov 23, 2015
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    No, the low into one side of the Ex-OR makes it non-inverting.
     
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