Advantages of Thermocouples and RTD over Thermistors
Because Thermistors are semiconductors, they are more susceptible to permanent de-calibration at high temperatures than are RTD’s or thermocouple.
The use of thermistors is generally limited to a few hundred degree Celsius and manufacturers warn that extended exposures even well below maximum operating limits will cause the thermistor to drift out of its specified tolerance.
Thermistors can be made very small which means they will respond quickly to temperature changes. It also means that their small thermal mass makes them especially susceptible to self-heating errors.
Thermistors are good deal more fragile than RTD’s or thermocouple and they must be carefully mounted to avoid crushing or bond separation.