Fan control apparatus

The utility model relates to a fan control apparatus includes a cisoid formula power supply circuit, a fan control circuit and a fan. This cisoid formula power supply circuit has once incline a current detection end to export an electric current signal, this fan control circuit has a comparing element and a switch element, this comparing element electricity is connected to and should once inclines the current detection end in order to receive this electric current signal to judge whether this electric current signal exceedes a critical value, works as to exceed this critical value, output no. 1 starts the signal, when no longer than this critical value, exports one and closes the signal, this switch element electricity is connected to this comparing element and should starts the signal and maybe should close the signal in order to receive to the electricity is connected to this fan, should start the signal when receiving, opens this fan, closes the signal when receiving, closes this fan. Whether this electric current signal exceedes this critical value, opens or close this fan, closes the purpose that the electric energy was saved to this fan when reaching low load by judging.