Resistance Thermometer

Resistance thermometers are a type of sensor used to measure temperature. They are also known by a number of different names including Resistance temperature detectors (RTDs), Platinum resistance thermometers (PRTs) or Pt100 sensors. Resistance thermometers are usually used to measure temperatures between -200 and 500°C. Resistance thermometers work by changing resistance with a change in temperature in a repeatable manner.
The metal has a high-temperature coefficient that means their temperature increases with the increase in temperature. The carbon and germanium have low-temperature coefficients which shows that their resistance is inversely proportional to temperature.

The resistance thermometer uses a sensitive element made of extremely pure metals like platinum, copper or nickel. The resistance of the metal is directly proportional to the temperature. Mostly, platinum is used in resistance thermometers. The platinum has high stability, and it can withstand high temperatures.

The following are the requirements of the conductor used in the RTDs:

1.The resistivity of the material is high so that the minimum volume of conductor is used for construction.

2.The change in resistance of the material concerning temperature should be as high as possible.

3.The resistance of the material depends on the temperature.