When the temperature is 80 degrees, the voltage is 2.3--2.5 when the temperature is 100 degrees, the voltage is 1.5-- 1.7, so the fixed resistance of 5 ohms can be added, and it is connected in series. The function of the water temperature sensor is to convert the cooling water temperature into an electrical signal, which is mainly divided into two categories. No matter what its internal structure is a thermistor, its resistance is between 275 ohms and 6500 ohms, and the lower the temperature, the higher the resistance, the lower the temperature.