A handheld thermocouple is a type of temperature sensor that is designed to be portable and used to measure temperature in a variety of applications. Handheld thermocouples typically consist of a thermocouple probe and a display unit, which are connected by a cable. The thermocouple probe is the part of the sensor that is inserted into the medium being measured. It consists of two wires made of different metals that are welded together at one end to form a sensing junction.