In article <19JUL199617484372@ubvms.cc.buffalo.edu>, NEIL GANDLER
<v064mb9k@ubvms.cc.buffalo.edu> writes
>
>
> I would like to make an operational amplifier based circuit
>that performs full wave rectification on a 1v p-p audio signal.
>I would like to keep voltage loss to a minimal (simple diode rectifier
>it out). Can anyone tell me of a simple way to use an op-amp as a
>no loss full wave recitifier? Distortion is not a concern. I am
>feeding the fullwave rectified audio signal into a peak detector.
>
> Neil Gandler
>
>
>
>
This is an old one I used
+--------2R-----------------+---10R----+
| /--------+---R-----\ | |
/-------+ | | | +----2R----+
| | | _____ | | |
| |\ | | /^\ D | +----||----+
-|-\ | | |\ ----- | | |
| >--+--R-+-|-\ | | /| | | |\ |
----|+/ | >---+---|< |--+-R-+-|-\ |
|/ /--|+/ | \| | >-----+----- output
| |/ D /---|+/
| | |/
-+-gnd------------------
this is also my first try at drawing in ascii.... probably my last too.
Probably a good idea to have a buffer (unity gain perhaps at the
output).
You can find this in most basic books but this one works well at about
100kHz with TL074 op amp. I also use a resistor pack as the internal
matching is pretty good and it can take up minimal pcb space. As for the
diodes any small signal ones are OK, I used 1N4148.
The capacitor is a small value depending on frequency response and
smoothing required.
Hope this is a help, even if it was a slow response...
Too many beers last night..
Good luck
--
Tony Hardman
Date: Sun, 21 Jul 1996 19:24:26 +0100
Original Subject: Re: No loss, small signal, full wave rectifier based on an op-amp?