Bill, > wanted to see if anyone in the group has had any experience using > ignitron tubes in "big coils",i have a couple that i'm going to use on > my 18,000 watt coil, anyone got any ideas? Ignitrons are mercury vapor switches and the deionization time is several tens of milliseconds. I've only seen them used in low rep-rate circuits like at one firing per second or less. They wouldn't be suitable for switching TCs. Pike