Is this a single pulse, or a series of pulses during the phase of the AC cycle?
If it is a series of pulses, the issue may have something to do with
instantaneous current, which is very high, if you turn the triac on anytime
other than zero crossing.

This is OK, the triac will get hot.  Make sure it is rated properly for the
load, and make certain you have it properly heatsinked.

-Adam

moshe wrote:
>
> HI FRIENDS.
>
> I'M  IMPLEMENTING  A DIMMER WITH A DIMMER I.C ( PHASE CONTROL )
> MY LOAD IS 100W INCADECENT LAMP AND THE INPUT VOLTAGE IS 230V 50HZ.
> THE POWER STAGE - INCLUDES TRIAC-PHILIPS-BT138, A SERIAL RFI CHOKE - 60
> microHenry,  A PARALEL CAPCITOR -100NF/275VAC , THE CAPACITOR IS PARALEL TO
> THE LAMP AND THE CHOKE.
> WHEN I TURN ON THE TRIAC BY APLYING CONSTANT CURRENT TO THE GATE - ALL ITS
> FINE.
> BUT, WHEN THE TRIAC GOT A PULSE IN IT'S GATE ( B.W=33 microsecond from the
> DIMMER I.C - EVERY HALF CYCLE.) AFTER SOME MINUTES ,THE TRIAC BECAME  VERY
> HOT!!!!!
> CAN ANYONE HELP ME TO SOLVE THE PROBLEM??
>
> THANK YOU VERY MUCH.
> MOSES.
> Email:moshe@gad-univ.com