What is the difference between open-loop and closed-loop control?

• A. Open-loop uses sensor feedback to adjust output; closed-loop has no feedback
• B. Open-loop has no feedback; closed-loop uses sensor feedback to adjust output
• C. Open-loop uses feedback only for speed; closed-loop uses it for position
• D. Open-loop is digital; closed-loop is analog

Answer: (B)

Open-loop and closed-loop control differ in whether the system uses feedback from the actual output to adjust what it does. In open-loop control, the input command is applied without measuring the result, so the action is the same each time regardless of what happens. This keeps things simple and fast but means disturbances or inaccuracies can cause the final outcome to deviate from the target. In closed-loop control, sensors monitor the output, compare it to the desired value, and adjust the input to reduce any difference. That feedback lets the system maintain the target even when conditions change or disturbances occur. The statement that open-loop has no feedback and closed-loop uses sensor feedback to adjust output captures this distinction.