"220V AC Cooling Fan" the greater the cooling capacity of the air volume is also higher, because the air ratio of the heat capacity is constant, with greater air flow, that is, the more air per unit time to take away more heat. Of course, the same air volume flow of the cooling effect of the wind the way. Speed signal "220V AC Cooling Fan" circuit output from the normal form of pulses, each wave is represented with the fan turned around, this signal may be provided directly to the host for display via the data bus. The "220V AC Cooling Fan" circuit outputs an alarm signal from the "High" and "Low" two states, meaning two levels represent generally in accordance with positive logic system, high "failure" "Low" indicates "normal."