I am looking to hand build a fan controller (bought one, uses PWM, don't like the "growl" at low to mid speeds), using potentiometers, and SPST switches to allow a complete off for the fans. The circuit I've got in mind, is something like the following (forgot to put the fans on it, they'd go between the potentiometers and ground) I'm not looking for anything "fancy", I don't need (but wouldn't mind) LEDs to indicate which fan is on or off. The fans I am going to be controlling are 120mm w/LEDs, and 80mm without LEDs. I am estimating around 2.8a for each fan, and the pots would be 3-4ohm max, maybe with a "full on" if I could find such a thing. I've tried to find articles on building such a circuit, almost all the ones I found are using PWM, instead, or are thermally controlled. BTW, I did try searching here for anything on "fan bus circuit" with no joy. Thanks.
Your circuit is good if you place the fans between the potentiometers and ground, however you should re check your values, for the amperage and resistance. There are many with a 0ohms setting for the full on you are looking for, and naturally make sure your PSU can provide the power for everything and that the wiring can source that amount of amperage.
Thanks! It's been a long, long, long time since I took basic electronics / electric in high school. I was plugging numbers into an Ohms law calc, so I wouldn't be suprised if the values are way off. Any suggestions? What about using 5K ohm pots, instead? I'm looking for a low voltage of around 7.5-8v. Thanks again. PS, as for the power supply handling all these fans, it already is. Just not speed controlled for them (yet) But thanks for the thought!
