demize wrote:Stupid question, but shouldn't I supply power to the red and black lines?
What do I do with the Control Line (blue).
My fan isn't spinning, this the dumb questions.
- Red is 12V (or whatever voltage you're using), i.e. "positive".
- Black is ground ("negative")
- Blue is PWM control
- Yellow is the tachometer signal
The PWM controls how fast the fan spins. Some fans have a pull-up resistor on the blue wire to ensure that the fan is always-on when disconnected; otherwise, the pin "floats" and the fan will spin, but slower than max-speed. Maybe it won't spin at all?
The PWM pin wants 5V, not 12V (assuming that's your power supply). You can't just connect that pin to your 12V supply or it might get damaged. If you're willing to solder up some resistors, you can create a voltage divider
. Your V_out is 5V, your V_in is 12V, and some calculated combination of resistors (from Amazon or elsewhere) will provide the correct voltage. You could also just buy a DC-DC converter that'll convert 12V to 5V like this