What is an RTD sensor

How does an RTD sensor work and what types of RTDs are there?

RTD stands for Resistance Temperature Detector, which refers to a temperature sensor. As the name suggests, it uses changes in resistance to sense temperature, but that alone may not tell you enough to know how an RTD works.

How does an RTD work?

As the temperature increases, the resistance of the RTD increases and vice versa. The control system or transmitter is constantly sending a current through the RTD sensor. As the temperature changes, the current resistance increases or decreases. Here the RTD detects this shift and reports it.

Suppliers build RTD sensors from a variety of materials. Platinum, copper, and nickel are widely used, with platinum being a big favorite because it offers the best stability in a wide range of temperatures.

Also, we can choose between two, three or four wire RTDs, but what does that mean? These wires create the compensation you need for the cable. Of course not with the two-wire option, so we should only choose it if we just need an approximate value. The three-wire option is the most common in many applications


Signal converter / isolator for RTD

RTD sensor types

Many factors influence the properties of an RTD sensor. Different materials such as platinum, copper or nickel can influence the range and linearity. Element types can also have effects, e.g. thin-film elements or wire-wound elements. Also, we can choose between two, three or four wire RTDs, but what does that mean? The most common version is three-wire, but each option has its advantages and disadvantages.

If you need help choosing the right temperature sensor for your application, take a look at our new intelligent temperature measurement wizard.

To learn more about RTD sensors, you can get in touch with our engineers!