[sdiy] Alternate VCO circuit in case you can't get that other one working

[Aaron Lanterman]

Dear Adam,

Here's another oscillator that uses the a CA3046 - but I think this  
one might be easier to make go, because there aren't any weird pots to  
tweak that might make things stop. Note it uses the same idea of  
keeping the CA3046 at a constant temperature. It also uses a 2N2907A,  
and you should be able to get 2N2222 from the stockroom (if not  
already in one of the labs, it's a very common transistor):

http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/opamp/AN-299.pdf

See Figure 1.

If nothing else, I think I understand this one much better. Read this  
writeup, I think you will too. It also has a hell of a lot less diodes.

Sorry I meant to send this to you sooner, but it took me a long time  
to find it. I'd seen it somewhere but couldn't remember where.

This design is similar to the Korg MS-20 - the two transistors at the  
top form something weird called a "thyristor."

Instead of the LF412, you could try an TL082 or LF353 (I have some  
353s in the bins).

- Aaron