Resistance Heating Alloy is a nickel-chromium electrical-resistance alloy for use at operating temperatures up to 2100. F (1150. C). It contains rare-earth additions for increased oxidation resistance, especially under conditions of frequent switching or wide temperature fluctuations. The alloy has low temperature coefficient of resistance, making it suitable for control resistors.
Resistance temperature detectors are sensors used to measure temperature by correlating the resistance of the RTD element with temperature. Most RTD elements consist of a length of fine-coiled wire wrapped around a ceramic or glass core. The element is usually quite fragile, so it is often placed inside a sheathed probe to protect it. The RTD element is made from a pure material whose resistance at various temperatures has been documented. The material has a predictable change in resistance as the temperature changes; it is this predictable change that is used to determine temperature.
Resistance Temperature Sensors is known as resistance temperature detectors. It is manufactured from platinum. The principle of operation is to measure the resistance of the platinum element whose resistance increases with temperature. Resistance temperature sensors are used to monitor the heat of hydration in mass concrete. It is suitable for the temperature supervision in gaseous media.
Resistance thermometers are made up resistance wire wound on a suitable former. They are widely used for accurate measurement of temperature. It consists of a small sensing element assembled into a temperature probe or other protective enclosure. It is particularly suitable for remote reading and can be made of inert materials like platinum. It is stable and shows almost no hysteresis with large temperature excursions. In the medical field, the resistance thermometer probes are best suited for rectal probe use.