Temperature control speed function (TC) uses thermistor to detect fan’s working environment, and then to change the fan speed. With TC function, the fan is at low speed while starting operating. When the working environment reaches to high temperature, it turns to high speed. When the working environment comes to normal ambient temperature, the fan returns to low speed. TC function gives the computer and electric equipment an extraordinary market effect, i.e. quiet effect while fan stand-by for rotating, and complete cooling effect while system in busy operation.