Hi All, Dr. Gary Johnson has written a very interesting paper on the input impedance of a MOSFET driven Tesla coil called "Input Impedance of a Tesla Coil". I scanned the pages and posted them (with his permission) at: http://www.peakpeak-dot-com/~terryf/tesla/misc/ The file names are GLJ-1.jpg to GLJ-9.jpg . They are large files to preserve the quality. Terry Fritz