Kevin, Are you really using 500Hz PWM rather than 100kHz (this is more than two orders of magnitude different)? If so, the required inductor will be more than "slightly" different. Regards, Dave "Kevin A. Benedict" wrote: > I am also using a 500Hz PWM, not 100Khz. > The fet and coil specs are slightly different ... -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.