All the functional parameters of a Stetron thermistor are thermal phenomena and time delay is inevitable. The Thermal Time Constant (τ) expresses the thermal response of a thermistor. It is defined as the time it takes a thermistor to reach 63.2% of the difference between an initial temperature and a stepped change in temperature under zero-power conditions. The following formula calculates the temperature change of a Stetron thermistor when exposed to an ambient temperature, TA (where TA < TB), to a zero-power condition. TB must be less than 100°C, for the effect of heat radiation to be ignored.
T - TA = (TB - TA) x e( -t/τ) (5)
Where:
τ is the Thermal Time Constant [s]
t is the elapsed time from the switch to the zero-power condition [s]
T is the thermistor temperature [°C] after time t
