| gain-wire |
Hi,
I am trying to build a DC follower/peak follower. It is my "design" so far, but so far the darn circuit isn't working like I want it to work. The goal is to have this op-amp (see attached file) take an AC signal and extract the DC component. THIS SHOULD BE SIMPLE! It amplifies an incoming AC signal, let's say for simplicity purpose, a 1kHz wave) and amplify by two, then rectify it with diode, filtering out any residual AC with the 220uF capacitor. Simple enough right? THIS SHOULD BE SIMPLE, YET IT AIN'T WORKING!
Well it doesn't rectify! I tried other diodes, I tried other capacitors, I tried even with different discharge resistors. The only time it ever works, sort of, is when I raise the value of the discharge resistor to about 200Kohms. When I vary my input signal's amplitude, then I get a corresponding DC level , which is what I want, but it keeps drifting back to a common DC level.
Any help? Please! I feel so stupid... |
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| AndrewT |
| dual polarity PSU |
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| gain-wire |
What? you mean use a dual polarity supply will suddenly make this work? Could you explain? I don't get it...
Really I don't see why, because I am already supplying the positive input with a bias voltage of 4 volts.
How will it help if the supply is bipolar?
Thanks. |
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| AndrewT |
| eliminate the 4.5V of output offset. |
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| udailey |
Gainwire,
I was in the forum and saw you needed old pots. It wont let me respond or email you. Email me and I will give you a list of Duncan Electronics, Helipot, and General Radio Corp pots.
Sorry for OT guys.
Uriah |
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