Which component generally provides feedback in a closed-loop control system?

In a closed-loop control system, the component that generally provides feedback is the sensor. The primary function of a sensor is to measure a specific process variable, such as temperature, pressure, or speed, and then relay this information back to the control system. This feedback is crucial because it allows the control system to compare the actual state of the process with the desired setpoint.

When the control system receives data from the sensor, it can determine whether any adjustments are necessary to maintain or achieve the desired output. For example, if a temperature sensor detects that a furnace is not reaching the set temperature, the control system can prompt an increase in heating output to correct the discrepancy. This continuous monitoring and adjustment cycle is what characterizes a closed-loop system, enabling it to respond dynamically to changes in conditions.

The other components listed, while useful in various functions within a control system, do not typically serve the primary role of feedback. An amplifier enhances signals, a switch enables or disables a circuit, and a transmitter is used to send signals rather than measure them. Thus, the sensor stands out as the essential element for providing the necessary feedback in closed-loop systems.