What is a thermocouple sensor?

Thermocouple sensor is perhaps the most simple and robust electronic temperature sensing devices imaginable. They consist only of two wires made out of dissimilar metals, attached together in a junction, which is placed where the measurement is to be obtained. Thanks to the Seebeck effect—named after German physicist Thomas Seebeck—if there is a temperature differential between the junction of these two wires, and their other measured ends are some distance away, there will be a voltage differential between them.When the temperature increases, the RTD’s resistance increases, and vice versa. The control system or transmitter constantly sends a current through the RTD sensor. When the temperature changes, the resistance on the current can increase or decrease. Here, the RTD detects this shift and thereby reports it.An RTD probe consists of a resistance element and insulated copper wires. The most common number of wires is 2; however some RTDs have 3 or 4 wires. The resistive element is the temperature sensing element of the RTD. It is usually platinum because as a material it is highly stable over time, it has a wide temperature range, it offers an almost linear relationship between temperature and resistance and it has a chemical inertness. Nickle or copper are also other popular choices of material for the resistive element.Bimetal thermometers are used in many different industrial applications, e.g. in machine building, in heating technology and in air conditioning and refrigeration technology. The wide variety of models of WIKA bimetallic thermometers offer a large selection of thermometers in a wide range of applications.

The model 52 bimetallic thermometer, with its case and stem made of stainless steel, represents the entry-level model among the process thermometers, but is also used for demanding applications in machine building.

The model A48 bimetal thermometer has been specifically developed for use in air-conditioning and refrigeration technology to measure the temperature in air ducts, whereas the model A43 bimetal thermometer was developed as a standard version for simple temperature indication in heating technology. As you can see, WIKA offers a suitable thermometer for every application. Our specialists will be happy to advise you on your selection.