Original poster: Charles Pike <ctpike-at-rcn-dot-com> I have been using an H bridge of Fairchild HGTG12N60A40 IGBT's for over a year to switch 2kW in my SSTC. They intially ran at 300kHz but I changed to a larger top load and the frequency dropped to 250kHz. I did not find any devices in the IR line which equal this performance. Charlie