Temperaturmaetning med Termistorer pa Passbitar (Temperature Measurement with Termistors of Gauge Blocks).

摘要

It is possible to use thermistors for temperature measurement with high precision of gauge blocks. The measurement uncertainty is estimated to within 5 mK. The advantages of thermistors are high resolution, insensitivity for electromagnetic interference, a low price, and if the measuring current is low, a low self-heating. Their greatest disadvantage is a lower stability but measurement in the future will show how much lower it is. Comparisons have been done between thermistors and platinum resistance thermometers (PRT) and with the measuring equipment which has been used, they have a higher self-heating and also the disadvantage with heating the gauge block. The greatest advantage of PRT is their higher stability. Because thermistors are non-linear two mathematical models have been used to fit the resistance of the thermistors to the temperature.