- Joined Mar 3, 2014
hello, I'm switching a small 12v fan on and off with a transistor (bc337) I've got an NTC variable resistor on the base up to the sipply and a 47k pot to ground. All works well when I warm up the sensor, the motor starts and goes off when it cools down. However when the transistor is off it starts to get hot. There is still about 40ma going through the motor windings. Is there a cure for this? Maybe it needs a diode or something?