CA3046 exponential converter

[Steve Varner]

I guess not many people have built the 3046 VCO and thermostat as shown in
Klein's book. The difference between this design and the AN-299 design is
that the matching transistors and one other transistor are used in the
standard VCO way, and the last two are used for temperature sensing and
heating. There is no transistor used for the clamp. I'll try this design
and let people know how it works.

SV


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Steve Varner wrote earlier:

> Barry Klein has a CA3046 exponential converter (fig.4-4, p.87) in his
> "Electronic music circuits." This is the same as the ENS-76 VCO option
> 1A found in the "Preferred Circuits Collection." These schematics show
> temperature compensation using the 2k tempco.
> Barry also has a CA3046 2-transistor thermostat circuit (Fig. 4-3, p.86)
> using the remaining transistors on the array (Q4 and Q5). It seems very
> simple. (I suppose you would then leave off the tempco resistor and
> replace it with a regular resistor.)
> Has anyone built this exact VCO setup? If it works well... godbye
> matched pairs and tempcos for me. 3046's only cost about 35 cents.
>
> (And yes, I have seen the AN-299 VCO circuit. Anyone actually built one
> of these into a VCO module?)
>
> Steve Varner
> mailto:varner at k-online.com