A thermocouple is composed of two dissimilar metal wires welded together to form a junction. This junction develops a small DC voltage proportional to the temperature measured at the junction. This voltage, or EMF, can then be measured by the instrumentation and converted into a temperature reading. Depending on the type of wire used in the element, or junction, the thermocouple can measure temperatures ranging from -184°C to +2330°C (300°F to +4000°F).
Protecting tubes, or wells, are used to protect the thermocouple junction. A wide variety of tube materials are available to accommodate many applications. To ensure minimum maintenance, the thermocouples have absolutely no moving parts.