Resistive Temperature Detectors (RTDs)

An RTD, or resistive temperature detector, is a sensor used to measure temperature. Made from either platinum, copper, or nickel, RTDs have a repeatable resistance vs. temperature relationship and an operating temperature range of –200°C to +850°C. RTDs contain a resistor that changes resistance value as its temperature changes. They have been used for many years to measure temperature in laboratory and industrial processes, and have developed a reputation for accuracy, repeatability, and stability. Platinum is a noble metal and has the most stable resistance-temperature relationship over the largest temperature range and is therefore more common than copper or nickel RTDs.

The PT100 is one of the most popular and accurate RTD sensors. Not only does it provide good accuracy, it also provides excellent stability and repeatability. Most standard PT100 sensors comply with the DIN IEC Class B standard. A PT100 sensor is also relatively immune to electrical noise and therefore well suited for temperature measurement in industrial environments, especially around motors, generators, and other high voltage equipment. Because RTDs have an accuracy of better than 0.1°C and repeatability, they are slowly replacing thermocouples in industrial applications below 600°C.

Signal Chains


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Reference Designs

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