Resistanssilämpötilaanturi

Resistanssilämpötilaanturi, often abbreviated as RTD (Resistance Temperature Detector), is a type of temperature sensor that uses the principle that the electrical resistance of most pure metals increases in a predictable way with increasing temperature. RTDs are known for their accuracy, stability, and wide temperature range.

The most common RTD material is platinum, due to its excellent linearity and stability over a wide temperature range. Other materials like nickel and copper are also used, but platinum offers superior performance. The resistance of a platinum RTD changes by a specific amount for each degree Celsius change in temperature. This relationship is standardized, with common types being Pt100 (100 ohms at 0°C) and Pt1000 (1000 ohms at 0°C).

To measure the temperature, a small, constant current is passed through the RTD. The voltage drop across the RTD is then measured, and since voltage, current, and resistance are related by Ohm's Law (V=IR), the resistance can be calculated. This resistance value is then converted to a temperature reading using established calibration curves or formulas. RTDs are often used in industrial process control, laboratories, and scientific instruments where precise temperature measurement is critical. Their robustness allows them to operate in harsh environments.