Which device can be considered a type of transducer in energy systems?

A thermocouple is considered a type of transducer because it converts thermal energy (temperature) into an electrical voltage. This ability to translate one form of energy into another is the defining characteristic of a transducer. In energy systems, thermocouples are commonly used for temperature measurement due to their reliability and wide range of operating temperatures. When a thermocouple is exposed to a temperature difference between its two junctions, it produces a voltage that correlates to that temperature difference, making it an essential instrument in monitoring and controlling thermal processes in various systems.

In contrast, a manometer is primarily a measuring device for pressure, not an energy transducer. Controllers, while they may process the signals from transducers, do not convert energy forms themselves but instead use the information provided to manage system outputs. Logic systems are involved in decision-making within a control system but do not function as transducers that convert physical energy into a different form. Thus, the thermocouple stands out as the correct answer because of its fundamental role as a device that converts temperature into an electrical signal.