[sdiy] Zener clipping Was : ...that 1K resistor on the output

[Neil Johnson]

Hi David,

> Although my circuit also uses two comparators in the core, it is  
> actually
> very different from your Tri VCO circuit, and is based on an  
> oscillator core
> which I haven't seen used in any other VCO.  I'm using the back-to- 
> back
> zeners as a clamp on the comparator output in such a way that they  
> also
> define the current to the integrator.  It's a pretty odd core, but
> simulations suggest is should work very well.

Oh, you mean like in the auxiliary oscillator in my three-phase LFO?

http://www.milton.arachsys.com/nj71/pdf/cesyg/vclfo-sch.pdf

The back-to-back zeners are D11 and D12 around comparator IC5A.  They  
clamp the output of the comparator and set the input current into the  
integrator IC1C / IC6A.

Cheers
Neil
--
http://www.njohnson.co.uk