What is a thermocouple?

• A. A device used to measure speed
• B. A temperature sensor made of dissimilar metals
• C. A mechanical component in rotating equipment
• D. A type of electrical connector

Answer: (B)

A thermocouple is accurately defined as a temperature sensor made of dissimilar metals. It operates based on the Seebeck effect, which involves the generation of a voltage when two different metals are joined at one end and subjected to a temperature difference. This voltage can then be interpreted to provide an accurate reading of the temperature, making thermocouples widely used for temperature measurement in various industrial applications, including rotating equipment.

The choice that states it is a device used to measure speed describes a different type of instrument, typically a tachometer or similar device, which is fundamentally concerned with monitoring rotational speed rather than temperature. The option that identifies it as a mechanical component in rotating equipment would refer to parts like bearings or shafts, which play roles in motion rather than in temperature measurement. Lastly, a type of electrical connector may pertain to a variety of connectors used in electrical circuits, but does not encapsulate the specific function of a thermocouple in temperature sensing. Therefore, the identification of a thermocouple as a temperature sensor made of dissimilar metals is a clear and precise answer.