what happens ?
_emitter_ to +12V, collector to load, base via a 10k resistor to 0V might fare a lot better
What can I do for controll the fan with positive side ?
Thank's to all...PBROUWER: Can you explain this better ? "If you use PWM to control the speed of the fan, the tachio output can be a bit noisy, you may need some filtering / debouncing."I Have resolved theproblem with a 4n35 optoisolator and a TIP137 PNP.If you break the negative, on the tachio cable ther is a 10V and is dangerous for the aurdiono's pin.