need analog voltage adder circuit

Discussion in 'General Electronics Chat' started by gregq, Sep 4, 2009.

  1. gregq

    Thread Starter New Member

    Jul 5, 2009
    I have a circuit which has a varying input. The circuit produces an output voltage proportional to the input. The output voltage varies from 0.4vdc to 8.6vdc. I need to add between 0.1vdc and 0.5vdc to the output voltage. I think an op-amp based summer can do the job, but I am not sure. The available supply voltage 13.2vdc to 14.5vdc. Any thoughts on how to build a analog summer? Also, any thoughts on how to generate the 0.1vdc to 0.5vdc signal from the supply voltage?

  2. beenthere

    Retired Moderator

    Apr 20, 2004
  3. mik3

    Senior Member

    Feb 4, 2008
    A simple op amp wired as a summing amplifier can do the job.

    To obtain a voltage between 0.1V and 0.5V use a pot with two resistors in series with it (one between it and ground and the other between it and Vcc) as to set the limits. You can put a capacitor between ground and the wiper to smooth out any noise voltage from the supply.