Thermocouple temperature probes consist of two wires, each made of a different homogeneous metal or alloy. The wires are joined at one end to form a measuring junction. This measuring junction is exposed to the fluid or medium being measured. The other end of the wire is usually terminated at a measuring instrument where they form a reference junction. When the two junctions are at different temperatures, current will flow through the circuit. The voltage resulting from the current flow is measured to determine the temperature of the measuring junction.