What is a controlled device that receives its signal from a controller?

A final control element is a component within a control system that receives a signal from a controller and acts to adjust the system's output to meet the desired setpoint. This could include valves, dampers, or actuators, which ultimately perform the actual control actions required to maintain system parameters, such as temperature, pressure, or flow rates at specified levels.

When a signal is sent from the controller, often based on feedback from sensors, the final control element it directs will modify the physical conditions in the system. For instance, if the controller determines that a pressure in a boiler is too low, it may send a signal to a control valve to open, thereby allowing more steam into the system to raise the pressure.

The other options refer to different elements within a control system. A control loop controller manages the process by generating the signal for the final control element based on the feedback it receives from sensors. A pressure sensor measures the pressure but does not control it. Similarly, a signal amplifier strengthens signals but does not perform any control function on its own. Therefore, the correct identification of a controlled device that directly receives its signal from a controller is a final control element.