Scaling, offset, LPF circuit not performing properly

Discussion in 'The Projects Forum' started by Tyler Bradbury, May 6, 2015.

  1. Tyler Bradbury

    Thread Starter New Member

    Mar 18, 2015
    I have the attached circuit set up in lab. It is supposed to scale the +-100mV input by 33, offset it by 2.5V, and LPF it. I have two clipping diodes at the end. The output is supposed to be centered at 2.5V, as shown in the picture.

    When I set it up in the lab, I do not get a wave at the output. I just get noise. I am using an LM324N that I have confirmed works. I have had another engineer check it out, and the circuit is correct. I am not getting an output. Is there anything obvious that I am missing?
  2. crutschow


    Mar 14, 2008
    If the simulation works to your satisfaction and you get nothing out of the real circuit, then I suspect an error in the wiring.
    Have you double checked all connections including the proper pins for signal and power/ground to the op amp?
  3. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
  4. Søren

    Senior Member

    Sep 2, 2006
    Or 16 - could be he was in a hurry and somehow entered the component number into the equation :D