On 08/10/2011 20:18, Peter Johansson wrote: > On Sat, Oct 8, 2011 at 2:42 PM, Michael Watterson wro= te: > >> You don't need ANY inductors! > Right. As Bob mentioned, an RC filter could be used instead of an LC > filter. I am familiar with the RC filter network for more generic > PWM, but as everything I saw WRT Class D amplifier design used LC > filters, I figured there was some specific advantage to using LC over > RC in this application. I probably should have thought to ask just > was that was in my original post. Can someone enlighten me here? > > BTW, many thanks for all the great help here! > > -p. it's to do with power and RFI. At low power levels you don't need RC either= .. At lower power ( < 1.5W) you can just connect FET or Transistor to PIC=20 and direct to 8 Ohm speaker. Use a >3W speaker or less than 50% duty=20 cycle as with a single FET you only can drive cone one direction. At 80kHz 16bits is 1/65K mark space and clock interval over 5MHz. 16bits=20 is not "free". Unless you are doing "hiFi" consider 8bit to 10bit (clock=20 256 to 1024 times frequency). --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .