Patent ID: 8392034

Claim:
An electronic apparatus, comprising: a casing having an inlet; a thermal sensor, disposed in the casing, for sensing a temperature relative to an interior of said electronic apparatus; a controlling unit, disposed in the casing and electrically connected to the thermal sensor, the controlling unit therein storing a function of speed versus temperature and receiving the temperature sensed by the thermal sensor; an air filter, detachably attached to the inlet of the casing, a partial structure of the air filter neighboring the thermal sensor blocking an airflow from flowing through the thermal sensor when the air filter is attached to the inlet of the casing; and a cooling fan, disposed in the casing and electrically connected to the controlling unit, wherein when the air filter is attached to the inlet of the casing, and when the air filter is not attached to the inlet of the casing, the controlling unit calculates a determined speed by applying the temperature sensed by the thermal sensor in the function of speed versus temperature, and controls the cooling fan operating under the determined speed to cool said electronic apparatus.