A thermocouple is a temperature sensor consisting of two different metal wires joined at one end. When this junction experiences a temperature change, it generates a small voltage that corresponds to the temperature difference. This phenomenon, known as the Seebeck effect, makes thermocouples reliable and widely-used temperature measurement devices.
Thermocouples are extensively used in furnaces, kilns, and high-temperature industrial processes. In metallurgical applications, they monitor molten metal temperatures, ensuring proper casting and forging conditions. Their ability to withstand extreme temperatures (up to 2,000°C depending on the type) makes them ideal for steel production, aluminum smelting, and other metal processing operations.
Thermocouples are constructed using various metal combinations depending on their intended applications. Common materials include chromel-alumel pairs, which offer versatility and wide temperature ranges. Other frequently used combinations include iron-constantan for moderate temperature applications and copper-constantan for lower temperature measurements. For high-precision work requiring exceptional accuracy, platinum-based alloys are often employed due to their stability and reliability.