[sdiy] cheap sine wave osc

[Dave Manley]

Derek Holzer wrote:
> Hi all,
>
> I'm planning a small light-activated installation, based a bit on the 
> Russian ANS synthesizer, and I'm wondering what the easiest, cheapest 
> sine wave oscillator I could construct would be. It will not be 
> voltage controlled, in fact the frequency of each of the oscillators 
> will be fixed, with tones produced by additive synthesis and the gain 
> controlled by photopotentiometers. Any suggestions for a chip/circuit 
> that I could easily make 64 or more of?
>
> thanks + best,
> derek
>
Take a look at Figure 13 in these college lab notes:

http://online.sfsu.edu/~sfranco/CoursesAndLabs/Labs/445LabsPDF/445Lab1.pdf

A sine osc with one opamp, two diodes, two caps and five resistors.

There is a pot shown, but this can be replaced with a selected resistor.

The frequency is set by R=R1=R2, and C=C1=C2, f=1/(2*pi*R*C).

-Dave

P.S. the author wrote a very good paper on discrete OTAs and their use 
in filters years ago:
http://yusynth.net/archives/ElectronicDesign/S-Franco-OTA-VCF-1974.pdf