RTDs (resistance temperature detectors) are one of the most common temperature sensor types used in industrial applications. Thermocouples and thermistors are popular temperature sensors as well, but RTD sensors are more accurate over a wide temperature range and more stable over time, making them an excellent choice for many applications.
An RTD sensor is essentially a resistor whose resistance value increases with temperature. Due to the predictable change in resistance of certain materials as temperature changes, it is possible to acquire highly accurate and consistent temperature measurements. Most RTD sensors have a response time between 0.5 to 5 seconds or more. RTD sensors can be constructed with pure platinum, nickel or copper. RTDs made with platinum are also known as PRTs (platinum resistance thermometer) and are the most frequently used given their higher temperature capabilities, stability and repeatability.
Specifications for RTD sensors include a base resistance value and a temperature coefficient of resistance (TCR) value. Typical base resistance values can range from 10 to several thousands of Ohms (?) depending on material and type. The base resistance value indicates the nominal resistance of the sensor at 0