[sdiy] Temperature stable lin-exp converter

[patchell]

    You can see an example of an expo converter I did using this
technique on this schematic...somewhere...

http://www.silcom.com/~patchell/seqproj/1001013.pdf

    The page is titled "Simple Temperature Compensated VCO.  It is on
page 10.  I just use a CA3046.  So far, it seems to work pretty good...I
am going to be testing it more this weekend.

jorgen.bergfors at idg.se wrote:

> >If one were to
> >take a third transistor and run a constant current
> >through it, the Vbe would vary with temperature. You
> >could then amplify the Vbe to a useful level and
> >polarity, and inject it into the summing node of the
> >expo converter input. I think this would give the
> >needed temp compensation. What do you think folks?
>
> Does the third tranny need to be matched? Or is it enough that it is
> thermally coupled to the other two?
>
> /Jorgen

--
 -Jim
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