A thermocouple is a type of temperature sensor that consists of two different metal wires or alloys joined together at one end. This junction of two dissimilar metals generates a voltage when there is a temperature difference between the two ends. This phenomenon is known as the Seebeck effect.

The voltage produced by the thermocouple is directly proportional to the temperature difference between the hot and cold ends. By measuring this voltage, one can determine the temperature at the hot junction. Thermocouples are widely used for temperature measurement in various industrial, scientific, and commercial applications.

Different types of metals or metal alloys are used to create thermocouples, and each type has its own characteristics, temperature range, and applications. Common types of thermocouples include Type K (chromel-alumel), Type J (iron-constantan), Type T (copper-constantan), and many others.

Thermocouples are known for their durability, simplicity, and wide temperature range, making them suitable for various environments. They are commonly used in industries such as manufacturing, petrochemical, aerospace, and food processing, as well as in laboratory and research settings.