"220V Cooling Fan" system is to automatically open and close the fan according to the prevailing temperature conditions, it can be very good save energy, but also facilitate the users to use more humane. And "220V Cooling Fan" on industrial production and daily life have a wide range of application temperature-controlled fan system, such as the cooling system of large machinery and equipment in industrial production, or limit laptops microcontroller based thermostat fans are able Start level automatically according to ambient temperature or stops, and to achieve speed automatically adjusted according to temperature changes, with a very wide range of uses in real life, so it's designed to have a certain sense of value. The temperature is controlled by a digital temperature sensor DS18B20 as the temperature sensing element. SCR connected in the power supply and the load "220V Cooling Fan", by changing the ratio of the ON and OFF in a given period of time to implement SCR speed control function, the design complete and easy to use, adapt to different occasions, people slept office It uses.