[sdiy] Tri to Saw converter produces a weird waveform

[Donald Tillman]

On Dec 13, 2025, at 12:06 PM, Scott Bernardi via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> I built a tri core vco and used a typical method to convert the triangle to a saw using the invert - noninvert of the triangle and adding the square back in.  Schematic and the waveforms I get are on this page:
> Weird Saw <https://www.bernacomp.com/elec/og2/weird-saw.html>
> 
> Any ideas what's going on and how to correct it?

The 2N7000 has a parasitic diode between the drain and the source, so it will start conducting if the drain goes more than 0.6V negative.

  -- Don
--
Donald Tillman, Palo Alto, California
https://till.com
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