3 pin connectors are usually used for the smaller chassis fans with lower power consumption. The internal diagram of a typical two wire fan is as follows.
Diagram 12v Computer Fan Wire Diagram Full Version Hd
Cpu fan wiring diagram. The connector of a 2 wire fan has a red and a black cable. 3 pin fan and 4 pin motherboard connector compatibility. Suggested electric fan wiring diagrams suggested primary cooling fan single speed onoff using 12 volt switching devices only for primary activation note. 4 pin connectors are usually used by cpu fans with higher power consumption. The red cable goes to the positive of the power supply and the black to the negative. Most stand alone adjustable thermostats ie.
A fan with a 3 pin power connector may be easilly fitted into desktop board with a 4 pin fan header. Fans and on board fan headers are backwards compatible. If you need to install a 3 wire computer fan forget the wiring diagram. Usually for more flexibility they have a male female 4 wire molex power connector. 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. The tacho signal from the fan sinks to ground for every revolution the input on the motherboard is pulled high.
Most computer motherboards come with a standard connector for the fan and it only fits one way. Chassis and cpu fans may use either 3 pin or 4 pin power connectors. If the connector fits the pins itll work and you dont have to worry about the pin arrangement. Hayden flex a lite or perma cool brands can provide a 12 volt output when activated.
Gallery of Cpu Fan Wiring Diagram
