Okay, my first post here. I am in the process of building a variable square wave tig, somewhat inspired by the link earlier in this thread.
I am using:
16 70A IGBT's
10 35A full bridge rectifiers
some doorknob Cap's
a 225A AC arc welder
some TSV diodes
and various small electronic components.
Unlike the machine in the plans, I am using an AVR microcontroller to drive the IGBT H-bridge.
Parts are in the mail on their way here now, but I am still trying to decide what to do about the HF spark gap and the HF coupling transformer. Would a spark plug be okay for a spark gap? and what diameter and number of turns would be best for HF-coupling with a Neon x-former?
so far my digikey bill is around a hundred bucks, the Igbt's were around $60 or so and the rectifiers were about 25 bucks. I priced the same parts out about 4 years ago and it was almost three times the price.
I'll post here on the "zone" with my progress in the coming weeks.