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From: corey@verdix.com (Corey Ashford)
Newsgroups: sci.electronics
Subject: Re: Geting my A/D converter to read current
Keywords: A/D TRIACs phase control
Message-ID: <635@verdix.verdix.com>
Date: 10 Aug 90 06:12:37 GMT
References: <5064@uafhp.uark.edu>
Sender: netnews@verdix.com
Reply-To: corey@verdix.com (Corey Ashford)
Organization: Verdix Western Operations; Aloha, OR
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In article <5064@uafhp.uark.edu> bbs00068@uafcseg.uucp (Joel Kolstad) writes:
... some stuff ...
>gave me a reading, but it's FAR from linear!  I assume because the voltage
>on a capcitor vs. time for an applied voltage is logrithmic, right?


Nope, unless there is a resistance in series with the capacitor.  Try
putting in a resistor before the cap such that R*C = .1 or so

from rectifier >-------/\/\/\-----*----> output
                                  |
                                -----
                                -----
                                  |
                                 gnd

By the way, I would suggest full-wave rectifying the output of the
op amp so that the filtering can be more effective.

- Corey Ashford