[sdiy] CA3046 VCO

[Oren Leavitt]

Stewart Pye wrote:
> Hi,
> 
> Is there a reason the CA3046 heated chip VCO designs don't seem very 
> popular? Would it be because the transistor matching is not so good, or 
> some problem (currrent draw?) with the heating scheme?
> 
> Regards,
> Stew.
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I built a few VCOs using the heated CA3046 scheme (something like 20 
years ago). They take several minutes to "settle" - that is completely 
warm up and stabilize.
Much happier and better results with the tempco resistor approach. Less 
current draw of course, too.
I believe praticality is the main reason. Heat shortens the life of 
semiconductors, too.

- Oren