The other name for this resistance thermometer is called as resistance temperature detectors which are temperature sensors that exploit the predictable change in the electrical resistance of some materials with the change in temperature. These resistance thermometers are almost invariably made using platinum which is why they are known as platinum resistance thermometers as these slowly replace the use of thermocouples for many industrial applications below a certain degrees sue to their accuracy and repeatability. The categories of this resistance thermometer includes carbon resistors, films and wire round types which are most widely used and there also exist advantages and disadvantages which talk about its peculiar and attractive advantages like these resistance thermometers are equipped with high accuracy, low drift and also has wide operating range.Limitations of these resistance thermometers includes that these are rarely used in industrial applications above 660 degrees which is why laboratory standard thermometers have replaced the metal sheath with glass construction. The other type of resistance thermometer is known as metal resistance thermometer which is an instrument used for measuring the temperature variation in control room. The advantages of this metal resistance thermometer is that there is more of accuracy and is more linear than thermocouple. This metal resistance thermometer gives out a performance is stable for long period and the disadvantages includes that this equipment is very expensive and the external current source is required.
These resistance thermometers are constructed in such a way that it offers a greater stability, accuracy and has repeatability in some cases than that of thermocouples. The reason that these resistance thermometers are made using platinum is because of its linear resistance temperature relationship and its chemical inertness as these resistance thermometers require small current which needs to be passed through the air in order which would determine the resistance. When these platinum resistance thermometers with thermistors are very much less sensitive to small temperature changes and also has a slower response time.
