Original poster: "claude masetto" <claudmas-at-optusnet-dot-com.au> Hello list, I have aquired some GTR modules. They are in a half bridge configuration and are rated 1000v 50 amp.I would like to use these for a SSTC. I am wondering if anybody has had experience with these and how to go about designing an isolated base drive circuit. I believe that the base has to be driven hard. Thanks Claude.