A thermocouple is essentially a temperature sensor (a device that measures temperature). It is made up of two wires of different metals that, when joined together, create an electrical junction. When the temperature changes at the junction it creates a voltage that can be interpreted to read the temperature. This is also known as the Seebeck effect. There is a wide range of thermocouples available, each with different characteristics, such as temperature range and their robustness. Each thermocouple is defined by a letter such as K-Type. Common types include J, K, L and T. The letters refer to the type of materials used and therefore the temperature they are usable at. For example, type J is iron and copper-nickel and is useable from around 0°C to 816°C, depending on other characteristics. Some thermocouples come with an additional sheath that insulate the wires to prolong their life.Thermocouples are ideal tools for the measurement of high temperatures and are a robust yet affordable solution.