Resistive temperature detector (RTD)
United Electric Controls
An RTD capitalizes on the fact that the electrical resistance of a material changes as its temperature changes. RTD's rely on the resistance change in a metal. The resistance will rise more or less linearly with temperature.
Traditionally, RTD's use a length of conductor (platinum, nickel iron or copper) wound around an insulator. Newer styles use a thin film of the conductor deposited on a ceramic substrate.
