<html><head><meta Name='keywords' Content='commtouch, pronto, mail, free email, free, branded, web based, free web based email, communications, internet, software, advertising banners, e-mail, free software'></head><body ><div align='left'><font ><blockquote><blockquote>crap, i put the wrong URL on here. The correct one is<BR>
<BR>
<BR>
http://darkwing.uoregon.edu/~nliebrec/Expo.pdf<BR>
<BR>
-nick<BR>
<BR>
<BR>
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<BR>
From: "Nick Liebrecht" <nick@dreamtheater.zzn.com><BR>
Sent: Wed, 5 Nov 2003 22:16:57 -0800<BR>
To: synth-diy@dropmix.xs4all.nl<BR>
Subject: exponential converter details<BR>
<BR>
<BR>
Hi all,<BR>
<BR>
I am having some trouble thinking through the typical expo converter<BR>
circuit. The circuit i'm referring to is posted here. <BR>
<BR>
http://darkwing.uoregon.edu/~nick/Expo.pdf<BR>
<BR>
It's taken from Barry Klein's book.I understand the CV ranging/scaling<BR>
part, but the actual current part is confusing me. I recognize the<BR>
actual current source built around the op amp, but I'm fuzzy about<BR>
what all the parts do, especially the capacitor. <BR>
<BR>
Can anyone explain this circuit to me? I want to learn why the<BR>
certain part values were chosen, and with what equations.<BR>
<BR>
Thanks in advance,<BR>
Nick Liebrecht<BR>
<BR>
<BR>
<BR>
A-ren-nen-nen-ah-ren-nen-nen<BR>
A-ren-nen-nen-uh-rennda<BR>
A-ren-nen-nen-ah-ren-nen-nen<BR>
A-rennda-rennda-rahhh <BR>
<BR>
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<BR>
<BR>
<BR>
<br><br><font><p align=left>A-ren-nen-nen-ah-ren-nen-nen<BR>
A-ren-nen-nen-uh-rennda<BR>
A-ren-nen-nen-ah-ren-nen-nen<BR>
A-rennda-rennda-rahhh </blockquote></blockquote></div></font></body></html>