adder circuit using opamp

Discussion in 'General Electronics Chat' started by Anne Rachel, Jan 22, 2013.

  1. Anne Rachel

    Thread Starter New Member

    Jan 22, 2013
    Can we make an adder using resistors and opamps to add any two numbers in the range of 1 to 100?
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    In theory, yes. You might want to define your numbers in tenths of a volt or hundredths of a volt to keep your total input at a workable range fore your op amp math. That is, 99 volts + 98 volts = 197 volts will get out of control. You will be much happier (and safer) using 9.9 volts + 9.8 volts = 19.7 volts. Be sure to use precision op amps and good techniques to limit errors introduced into your adder. Also make sure your op amps can handle the full voltage range you decide to use (input and output).

    Remember, in theory, there is no difference between theory and practice. In practice, there is.
    Anne Rachel likes this.
  3. Papabravo


    Feb 24, 2006
    Sure. It was my 7th grade science project and I didn't even use op amps, just pots, a resistor, a meter and some wire.
  4. crutschow


    Mar 14, 2008
    Just remember that for correct operation, all the input voltages representing a number must be accurate to much better than 1% of full scale (depending upon the number of inputs for numbers being added). That's the rub with analog electronics. :rolleyes:
    Anne Rachel likes this.