Which statement about closed-loop control is NOT true?

• A. It uses feedback from sensors to adjust the control action
• B. It does not use sensors to modify the output
• C. It can compensate for disturbances
• D. It can improve tracking accuracy

Answer: (B)

Closed-loop control relies on measuring the actual output with sensors, comparing it to the desired reference, and using the resulting error to adjust the actuator input. That feedback path is what lets the system modify its action based on what’s actually happening, rather than just following a pre-set plan. Because the output is continually monitored, the loop can counteract disturbances like unexpected loads or external forces by correcting the input to bring the output back toward the target. This feedback action also helps improve tracking accuracy, reducing both steady-state and transient errors over time. The statement claiming no sensor use contradicts the very mechanism of closed-loop control, so it is not true.