This is a last ditch since i haven’t been able to solve this myself, only getting more confused.
This is for a car’s dash lights (LED’s) so I’m switching the supply side not the ground side.
I have a mini 05 driving a BC557/547 pair. This output drives a test LED in proportion to a pot as expected.
I put a NPN P36NF06L transistor on it (G to +5v signal, D +12v, S to LED’s) and it seemed to drive a test
When it was installed, the dash LED’s are barely on with the pot to the stop.
So i changed the P36 to a PNP TIP137, same connections, and something started smoking.
What do i have stuffed up?