Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum, nickel, or copper.This sensor measures temperature using an RTD (Resistive Temperature Detector). The sensor has a built-in thermistor which allows it to measure temperatures up to 100 degrees Celsius. This sensor can be used as a stand-alone device or combined with a thermo-hygrometer.