PTS AT temperature sensors are classified as Resistance Temperature Detectors/Resistive Thermal Devices or in short, RTDs. The most important and central element used in the production of the PTS AT is platinum. Platinum has an inherent, unique, repeatable and predictable (high long term stability) resistance vs. temperature (RT) relationship. The RT relationship is characterized as the amount of resistance change of the sensor for each degree of temperature change, also known as the temperature coefficient of resistance (TCR). The TCR of the PTS AT is positive and nearly linear (i.e. the resistance of the sensor increases in a linear fashion as the temperature of the device rises). The thin film of platinum also offers a low thermal mass, making the response time faster and packaging in small assemblies easier. Just like other RTDs, the PTS AT is classified using a reference temperature of 0°C. It must be noted however, that even though the PTS AT is highly accurate its sensitivity to temperature change is moderate.