BabyGeezer:
i see, looks like i still can't do the test yet then, no heatsinks yet.just to be sure though, from the datasheet;
it says Maximum Power Dissipation is PD=(TJ(max)- TA) / *0JA (*0 is actually theta)
that becomes PD=(150-33)/19 = 6.16W
so; it won't handle 7W, right ?
That's using a PCB as heatsink or nothing as heatsink, using a block of copper that 19 becomes 3, and the power handling is 30W for
a 90 deg rise above ambient. Personally I'd not recommend trying to more than 20W out of a TO220 package
as you have to allow for the heatsink itself and any thermal pad or grease.