What is an example of an application that might use a closed-loop control system?

A closed-loop control system continuously monitors the output and adjusts the input to maintain the desired level of control, making it reactive to changes. Thermostats exemplify this concept perfectly, as they measure the current temperature in a space and compare it to a set point (the desired temperature). If the actual temperature deviates from the set point, the thermostat will send a signal to the heating or cooling system to adjust and bring the temperature back to the desired level.

In contrast, applications like simple light switches operate on a binary on/off function without feedback, digital clocks require manual adjustment without real-time input for regulating time, and manual steering mechanisms do not incorporate automatic feedback control processes. Therefore, the thermostat stands out as a clear representation of a closed-loop control system due to its feedback mechanism.