In sci.electronics.design Tauno Voipio wrote:

snip

There are many components without types or values, so
I had to guess them.

There are plenty of issues, beginning with the slot in the
triangle at the positive tip, die to the retrun time of
the ramp signal.

The output capcitors are left out of the simulation, I do
not have a mode for a reversed electrolytic.

Fantastic! Thank you for all of your hard work. It will take me a few
days to digest it all.
Meanwhile, my pertinent notes on UJT models are available online, at
the link shown below. Among other things, it contains a 2013 usenet
thread where the late Jim Thompson compares the UJT model you used with
a couple of others.

https://crcomp.net/paia/ujt.php

Danke,

--
Don, KB7RPU
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.