Scaling, offset, LPF circuit not performing properly

Thread Starter

Tyler Bradbury

Joined 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?



Joined 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?