A Resistance Temperature Detector (RTD) is a type of temperature sensor that measures temperature by correlating the resistance of the sensor element with temperature. Typically made from pure metals like platinum, RTDs exhibit a predictable change in resistance as temperature varies, making them highly accurate and stable over a wide range of temperatures. RTDs are commonly used in industrial applications, laboratories, and HVAC systems due to their precision and reliability. They can be configured in various forms, such as wire-wound or thin-film, and are often used in conjunction with thermocouples and other temperature measurement devices for enhanced performance.