Triac Power?

[Texton]

Hi guys..

Can anyone tell me how the power in a Triac is calculated?..

AND will the power in the Triac be different if the supply is DC instead of AC ?

 

[(*steve*)]

A triac won't turn off if you use DC

The power is essentially given as the RMS current times the voltage drop (which can be in the region of 1 to 4 volts depending on current) plus a little for gate dissipation (which is hopefully low)

 

[john monks]

Generally speaking a close approximation of the power dissipation in a triac is the average forward current times the "ON" forward voltage. Typically this voltage is less than 2 volts. For example the typical forward voltage drop in an 2N5445 is 1.7 volts in the "ON" state. This is good if you are using 50 or 60 hertz but may be much more if you are using a much higher frequency because of the turn on transition time. As Steve says the gate adds a little bit more.
When you say DC instead of AC what do you have in mind?