RTDlämpömittarit

RTD lämpömittarit, or Resistance Temperature Detectors, are temperature sensors that work on the principle that the electrical resistance of certain metals changes predictably with temperature. Commonly used metals include platinum, nickel, and copper. Platinum is favored for its stability, wide temperature range, and linearity, making it the most prevalent choice for RTDs, especially in industrial applications.

An RTD consists of a thin wire or film made of a metallic conductor wound around a ceramic or glass core, or deposited as a thin film on a substrate. As the temperature increases, the atoms within the metal vibrate more vigorously, impeding the flow of electrons and thus increasing the electrical resistance. Conversely, as the temperature decreases, the atomic vibrations lessen, and the resistance drops.

The relationship between resistance and temperature for an RTD is generally well-defined and can be described by mathematical models or lookup tables. To measure temperature, a small, constant current is passed through the RTD, and the resulting voltage drop across it is measured. This voltage is then converted into a temperature reading using the known resistance-temperature characteristics of the specific RTD element. RTDs offer good accuracy and repeatability, making them suitable for a wide range of temperature measurement tasks in fields like manufacturing, laboratory equipment, and HVAC systems.