Thermocouple is the most universal, expedient, and versatile device used to measure  temperature. It is a sensor that measures precise temperature within a wide range. Manufactured by joining together two dissimilar metals at one end, the thermocouple alloys are usually in the form of wire. A reference junction is also included at the opposite ends of the parent material. By heating or cooling the junction between dissimilar metals, a temperature gradient is produced, which generates a voltage. This voltage is converted into units of heat calibration at the ends of thermocouple wires. The heat generated is converted into useable units that serve as input signals for controllers. Thermocouples are suitable to be used in temperature ranges from -200 to 2316 °C [-328 to 4200] °F. Widely used in high temperature applications, they are less expensive in most cases and can withstand higher temperatures than RTDs.