MOSFETs:
When I was still an apprentice (early 1980's) I was helping put together a switched mode PSU they were playing with in the lab complete with a birds nest ball of components (none of this fancy breadboard stuff!).
connecting up to a load bank of big resistors, after we had been testing most of they day I decided to have one more play and turned up the wick a bit too much......I got a lesson in thermal runaway as the output voltage slowly dropped until there was a POP! and glowing balls of the MOSFET innards went floating across the bench.
Got a good lesson in learning about heatsink design - those devices were bloody expensive in those days!
Biting the hand that feeds IT
