"Small Cooling Fan" with a CPU cooling fan, graphics card cooling fan, notebook cooling fan, north (south) bridge cooling fans, chassis cooling fans, hard drive cooling fan, power supply cooling fan. The basic structure of the cooling fan is generally composed of motors, bearings, blades, housing (including fixing holes), power plugs and wires of several parts. Motor is the heart of "Small Cooling Fan" in general by the stator and rotor of two parts. Motor running when stationary part called the stator. Runtime rotating part called the rotor. DC motor speed control mode has two voltage control and frequency modulation speed. The latter is the mainstream applications. May well achieve the "Small Cooling Fan" on-demand control speed.