When it comes to control "220V Cooling Fan", replace the thermocouple thermistor practice has become more prevalent. Using a thermistor to control the temperature is not new, the device was used to measure the temperature of the heat sink PCB-off and landing. This article will explore the performance of its work and the fan control to reduce noise, and improve efficiency. In the thermistor-based "220V Cooling Fan" control, if the ambient temperature rises above room temperature, temperature rise bridge will detect the temperature and turn on the fan. This job is fully automatic, when the ambient temperature is returned to room temperature, the fan will be turned off. Negative temperature coefficient (NTC) thermistor can be very effective in detecting the rise in the ambient temperature. Because it is a negative temperature coefficient, when the ambient temperature rises, the thermistor resistance will be reduced. In this case the temperature of the bridge in the process control "220V Cooling Fan" work, the use of this unique feature is that the thermistor.