Automobile Air Conditioner Evaporator and NTC Thermistor

NTC thermistor is a semiconductor ceramic component with a very large negative temperature coefficient. It is made of manganese, cobalt, nickel and other metal oxides after high temperature sintering. Its resistance value changes with ambient temperature or self-heating due to passing current, that is under a certain measuring power, the resistance value decreases with the increase of temperature. Using this feature, the NTC thermistor can determine the corresponding temperature by measuring its resistance, so as to achieve the purpose of detecting and controlling the temperature.

The composition of the automobile temperature control system includes a temperature sensor, a control system ECU, etc. The temperature sensors include an outside air temperature sensor, an inside air temperature sensor, and an evaporator temperature sensor. 

Automotive air-conditioning evaporators generally install NTC thermistors near the heat sink to detect the ambient temperature. When the surface temperature of the evaporator is lower than the set minimum temperature limit, the compressor is controlled to stop running, and when the surface temperature of the evaporator is higher than the set maximum temperature limit, the compressor starts to work. This just takes advantage of the temperature sensor characteristics, and the resistance value decreases with increasing temperature. This prevents freezing of the air conditioning ducts.

Exsense sensor is a manufacturer specializing in the production of  NTC temperature sensors and NTC thermistors.Exsense produces thisNTC temperature sensor for automotive air-conditioning evaporators. It uses NTC resistance elements. The material is made of waterproof nickel-plated copper probe and blue sheathed wire. The product has the characteristics of stable signal transmission, high precision and high range.