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I have a design for a precision rectifier that isn't working as I would like it to on a breadboard. I've attached the schematic below (VF1/VF2 are metering nodes). It is being fed by a preamplifier (low noise, 20-22kHz) with a buffer as the last thing on the output. Everything works well in simulation, but when I transfer it to breadboard, I find that (while it is rectifying) the dc offset is filtered out. For example: if I play a 400 hz sine wave (with no dc offset) through the rectifier at 12 Vpp, I get this:

oscilloscope reading with 12Vpp input

I have put many capacitors as close as possible to the rails feeding the op amp, as well as rebuilding the circuit multiple times. The rails seem stable.

I tried to upload a picture of the breadboard but thought it wouldn't be very helpful as it is pretty messy. If it seems like the problem is related specifically to that, I can upload. Perhaps though, someone could point out an issue with my schematic, or even a more robust precision rectifier design that would work better on the breadboard? Thank you!

Edit: For reference, I am using this as a part of a circuit for a color organ: using sound to control lights. I need the precision rectifier to be fairly accurate and responsive.

Power Section

Rectifier

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    \$\begingroup\$ Is your scope set to DC-coupled inputs? \$\endgroup\$
    – Hearth
    Commented Oct 11, 2023 at 20:27
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    \$\begingroup\$ @Hearth It reads "AC" in the photo of scope menu \$\endgroup\$
    – Justme
    Commented Oct 11, 2023 at 20:30

1 Answer 1

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You have your oscilloscope set to measure AC. When this is activated, DC is removed: -

enter image description here

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