Why did a 1k resistor solve my problem?
I wanted to control a 3 wire computer fan with PWM(25 kHz 50% duty) from my Arduino NANO pin 10. My Circuit was very simple. I had an IRLB8721F N-Channel MOSFETn a dell HU843-A00(delta ) Chassis fan, a 4148 flyback diode and a pc power supply which I rigged to output 12v. The Arduino was plugged into my computer's USB.
This is the circuit, except I didn't have the 1k resistor in place.
With out the resistor the fan was squealing and wouldn't run, but with the resistor it was quiet and ran successfully.Why did the resistor solve my problem?