The air conditioning special-purpose temperature sensor for the negative temperature coefficient thermistor, is called NTC, its resistance number reduces along with temperature increment, reduces along with the temperature increases. 25℃ the time resistance number is a nominal value.

The NTC common breakdown for the resistance number fill-out, the opening, is affected with damp gets moldy and spoil the resistance number change, the short circuit, the plug and the place contact not good or the leakage and so on, causes the air conditioning CPU examination terminal voltage exceptionally to cause the air conditioning breakdown. Air conditioning commonly used NTC has room of inner rim warm NTC, indoor serpentined NTC, outdoor serpentined NTC and so on three, the upscale air conditioning also using outer ring warm NTC, the compressor inspiration, exhausts NTC and so on.

NTC mainly has as shown in Figure in the electric circuit one two usages, the temperature change causes the NTC resistance number change, the CPU post voltage also along with it change, CPU to decide air conditioning's active status according to the voltage change