This is the response I got from driving a solid state relay SSR, with a pwm around 200hz steps in the wave form.
I not sure how the triac is picking up the zero crossing threshold too complete the steps in the wave form.
I benched this the way shown & tried with out the transformer on my heat gun, both work at the full range of the pot.
Different loads respond a little different. I think this will work for my drill press.
The SSR is rated at 25amp and on a large heat sink, I'm sure with extensive use it will need a CPU fan too keep cool.
