On Friday, 22 December 2017 17:32:13 UTC, The Natural Philosopher wrote:
On 22/12/17 15:18, tabbypurr wrote:

FWIW silicon devices are often specced to give claimed P_diss at unrealistic case temps, I wouldn't assume any better for other components.

Indeed. But that is not a true usbale 'rating' - that is a measure of
chip to case thermal conductivity.

of course

There is no other way to specify it for a power transistor bolted to a
heat sink of unknowable thermal resistance in an equally unknowable
ambient airflow.

Of course there's another way, give a power figure for realistic conditions. It's marketing innit.


NT