Platinum resistance thermometers are remarkable instruments. They operate over the range-260°c to 960°c with accuracies approaching 1mK. They can be cycled repeatedly over hundreds of degree Celsius. They are unlike other temperature sensors that require external stimulation in the form of measuring current or voltage. It works on the principle of resistance through a fine platinum wire as a function of temperature. There are two types of thermometers, which includes ceramic and glass coated ceramic .The ceramic PRT's are usable over the temperature range -200 degrees C to 750 degrees C. The glass coated ceramic PRT's are usable over the range -100 degrees C to 550 degrees C.