Which of the following describes an open-loop control system?

An open-loop control system is characterized by its operation without feedback. In such a system, the control action is established based on predetermined input parameters without considering the actual output of the system. This means that the system cannot adjust its operations based on the results of its previous actions.

For instance, consider a simple home heating system that is set to turn on at a certain temperature regardless of whether that temperature is actually achieved or maintained. It does not monitor the room temperature and cannot make adjustments if the desired temperature is not reached; once the control action is initiated, it does not modify its behavior based on output results.

This principle differentiates open-loop systems from closed-loop systems, which utilize feedback to adjust operations based on the output. Therefore, the defining quality of an open-loop control system is its independence from feedback mechanisms in guiding its operations.