I'm in the midst of a similar light dimmer project (110V, 500W, Phase
     delay triac).  I'm in a quandry over the value of the series choke.
     They're either too big and hog board space, too small (seem to have no
     effect), or too expensive.  Best so far is a home wound 35 turn on a
     surplus torroid core (From www.bgmicro.com).  I have no specs on the
     core and 35 turns is downright painful on the fingers. Anyone have any
     rules of thumb on how much filtering is enough???  Some vendors spec
     by the milliHenry, others publish current/rise time specs only.  Any
     suggested sources for parts?
     Joe (Atlanta)



     Big Snip----------
      lighting industry (at least where I work
     http://www.dovesystems.com) uses phase controlled triacs (or solid
     state relays) with a   >>>>>>>>>>>series choke<<<<<<<<<    to limit
     rise time.  Again, some use FETs or IGBTs, still switching at 60 (or
     50) Hz, but with a slower rise time, making the choke unnecessary, but
     suffering low efficiency.