[sdiy] exponential converter details

[Ray Wilson]

I totally agree with Jay Rene's site is awesome. Also you are looking at
only a part of the necessary circuit for the complete convertor you can look
here:

http://atlas.csd.net/~rjwsoft/OctVCO_LM394_FixedSquare.html

Cheers

Ray
  -----Original Message-----
  From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Jay Schwichtenberg
  Sent: Thursday, November 06, 2003 11:04 AM
  To: synth-diy at dropmix.xs4all.nl
  Subject: RE: [sdiy] exponential converter details


  Nick,

  You might try Rene's WEB site: http://www.uni-bonn.de/~uzs159/  "Whats
that exp and tempco stuff?" That will give a general overview. The cap in
the circuit is to stabilize the circuit and keep it from oscillating.

  Jay
    -----Original Message-----
    From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Nick Liebrecht
    Sent: Thursday, November 06, 2003 8:37 AM
    To: synth-diy at dropmix.xs4all.nl
    Subject: [sdiy] exponential converter details


        crap,  i put the wrong URL on here.  The correct one is


        http://darkwing.uoregon.edu/~nliebrec/Expo.pdf

        -nick


        ---- Begin Included Message ----

        From: "Nick Liebrecht" <nick at dreamtheater.zzn.com>
        Sent: Wed, 5 Nov 2003 22:16:57 -0800
        To: synth-diy at dropmix.xs4all.nl
        Subject: exponential converter details


        Hi all,

        I am having some trouble thinking through the typical expo converter
        circuit.  The circuit i'm referring to is posted here.

        http://darkwing.uoregon.edu/~nick/Expo.pdf

        It's taken from Barry Klein's book.I understand the CV
ranging/scaling
        part, but the actual current part is confusing me.  I recognize the
        actual current source built around the op amp, but I'm fuzzy about
        what all the parts do, especially the capacitor.

        Can anyone explain this circuit to me?  I want to learn why the
        certain part values were chosen, and with what equations.

        Thanks in advance,
        Nick Liebrecht



        A-ren-nen-nen-ah-ren-nen-nen
        A-ren-nen-nen-uh-rennda
        A-ren-nen-nen-ah-ren-nen-nen
        A-rennda-rennda-rahhh

        ---- End Included Message ----






        A-ren-nen-nen-ah-ren-nen-nen
        A-ren-nen-nen-uh-rennda
        A-ren-nen-nen-ah-ren-nen-nen
        A-rennda-rennda-rahhh
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