RTDlämpömittarin

RTD lämpömittari, which stands for Resistance Temperature Detector, is a type of temperature sensor that operates based on the principle that the electrical resistance of certain metals changes predictably with temperature. Unlike thermocouples which generate a voltage, RTDs rely on measuring the resistance of a sensing element. The most common materials used for RTD elements are platinum, nickel, and copper. Platinum is favored for its stability, accuracy, and wide temperature range, though it is also the most expensive.

The basic construction of an RTD involves a wire or film of the resistive material wound around a ceramic or glass core, or deposited as a thin film onto a substrate. This element is then encapsulated to protect it from the environment. When current flows through the RTD element, its resistance is measured. By knowing the relationship between the material's resistance and temperature, the temperature can be accurately determined.

RTDs are known for their excellent accuracy and repeatability compared to other temperature sensing technologies. They offer a linear relationship between resistance and temperature over a broad range, making them easier to calibrate and use. Common applications include industrial process control, laboratory measurements, food processing, and automotive systems where precise temperature monitoring is crucial. The typical three-wire or four-wire configuration is employed to compensate for the resistance of connecting wires, further enhancing accuracy.