First, the chosen "Waterproof Cooling Fan" must be able to provide enough exhaust volume (speed), under the conditions of high temperature hot air inside the cooling equipment; when the temperature is relatively low and less when hot air is to do the opposite work. Secondly, the position of the sensor should be installed at the selected note to the sensor in the proper position, as far as possible "Waterproof Cooling Fan" sensors can be clamped directly to the surface to be cooled. In operation, a temperature-controlled fan speed will be faster if the operation feeling of the thermistor at higher temperatures; and at lower temperatures, it will operate at a lower speed; at these higher and lower the intermediate, "Waterproof Cooling Fan" speed is hardly changed due to temperature.