[sdiy] LM13700 Oscillator Circuits and analog computers

[Ian Smith]

Hello all,

I was advised to look at the application notes for the LM13700 and I have a few questions. On the Triangular/Square-Wave VCO, would replacing Ra with a potentiometer allow the changing of the frequency ? On the Ramp/Pulse VCO, I would assume replacing R2 with a potentiometer would allow for the varying of the frequency, but how exactly would one vary the width of the pulse output and the length between the pulses? 

Also, what would someone use a Voltage-controlled Resistor for?

And finally, after reading the "Chaotic Sound Synthesis" article by Dan Slater, does anyone know where I can find schematics for the Comdyna GP-6 or even where to purchase one of these rather cool looking gadgets?

-Ian Smith
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