termoparer

Termoparer, or thermocouples, are temperature sensors that rely on the Seebeck effect. When two dissimilar metals are joined at one end (the sensing junction) and connected to a measurement circuit at the other ends, a small voltage is generated that is proportional to the temperature difference between the sensing junction and a reference junction. The reference junction is kept at a known temperature, typically using cold-junction compensation in the measuring instrument.

Thermopar assemblies consist of a pair of wires of different metals sealed in a protective sheath. Common wire types include Type K (Nickel–Chromium / Nickel–Alumel), Type J (Iron / Constantan), Type T (Copper / Constantan), Type E (Chromel / Constantan), and Type N (Nicrosil / Nisil). Each type has its own approximate usable temperature range and sensitivity, with Type K suitable for widely varying conditions and ranges up to about 1260 °C in many applications.

Applications of thermoparlar are broad and include industrial process control, furnaces and kilns, combustion monitoring, laboratory experiments, and engine or turbine exhaust monitoring. They are favored for their simplicity, ruggedness, wide temperature range, and relatively low cost. Limitations include nonlinearity across broad ranges, drift with time, and susceptibility to oxidation or contamination at high temperatures. Accurate use relies on proper calibration, appropriate sheath material, correct wiring, and cold-junction compensation. Standards such as IEC 60584 and related regional specifications define tolerances, calibration methods, and testing for thermocouples.