PWM fan adjustment "220V Cooling Fan" Speed is to obtain information directly from the CPU temperature, the fan without any temperature measuring device. Depending on the CPU temperature, the thermostat will have a different fan speed adjustment corresponding, and fan speed changes can be done four five, or even more, basically feeling infinitely variable. Since the pulse signal is adjusted in real time, is very sensitive to changes in the fan speed, CPU speed and temperature changes are almost synchronized. "220V Cooling Fan" in computer standby time, it can be maintained at a very low speed. In standby time, CPU temperature in the following four or five degrees, the speed is only about one thousand turn, greatly reduces the running noise. The designed maximum speed of more than 2000 rpm, only the CPU temperature close to the limit temperature, ie 65-67 degrees time to appear. Compared to conventional thermostat "220V Cooling Fan" has a greater range of speed control, a better solution to the problem of noise and performance.