Most stand alone adjustable thermostats ie. Most computer motherboards come with a standard connector for the fan and it only fits one way.
Proprietary Fan Header Issues Dell Community
Cpu fan wiring diagram. 3 pin fan and 4 pin motherboard connector compatibility. I could not find much on how to make the the 4 wire cooling fans so i made this video for using the fan with a voltage controller. Fans and on board fan headers are backwards compatible. The tacho signal from the fan sinks to ground for every revolution the input on the motherboard is pulled high. The connector of a 2 wire fan has a red and a black cable. Suggested electric fan wiring diagrams suggested primary cooling fan single speed onoff using 12 volt switching devices only for primary activation note.
Usually for more flexibility they have a male female 4 wire molex power connector. Hayden flex a lite or perma cool brands can provide a 12 volt output when activated. Chassis and cpu fans may use either 3 pin or 4 pin power connectors. 3 pin connectors are usually used for the smaller chassis fans with lower power consumption. If the connector fits the pins itll work and you dont have to worry about the pin arrangement. A fan with a 3 pin power connector may be easilly fitted into desktop board with a 4 pin fan header.
The red cable goes to the positive of the power supply and the black to the negative. If you need to install a 3 wire computer fan forget the wiring diagram. 4 pin connectors are usually used by cpu fans with higher power consumption. The internal diagram of a typical two wire fan is as follows.
Gallery of Cpu Fan Wiring Diagram
