PT100 platinum resistance thermometers (RTD’S)


Platinum resistance thermometers (PRTs) offer excellent accuracy over a wide temperature range (from –200 to +850 °C). Standard sensors are available with various accuracy specifications and numerous packaging options to suit most applications. Unlike thermocouples, it is not necessary to use special cables to connect to the sensor.

The principle of operation is to measure the resistance of a platinum element. The most common type (PT100) has a resistance of 100 ohms at 0 °C and 138.4 ohms at 100 °C.

The relationship between temperature and resistance is approximately linear over a small temperature range: for example, if you assume that it is linear over the 0 to 100 °C range, the error at 50 °C is 0.4 °C. For precision measurement, it is necessary to linearize the resistance to give an accurate temperature. The most recent definition of the relationship between resistance and temperature is International Temperature Standard 90 (ITS-90).

The Resistance Temperature Detector (RTD) is one of the most accurate temperature sensors available. Unlike thermocouples, RTD’s do not de-calibrate (drift), thereby ensuring excellent repeatability.

Our RTD’s are available in various diameters, the most common being 6mm. Other diameters available are: 4.5mm, 8mm, 10mm, 12mm and 12.7mm.

Mineral insulated RTD’s (up to 350ºC) are available in 3mm and 6mm sheaths. As with our thermocouples, any configuration is possible.