Closed loop or closed-loop may refer to:

Mathematics

• Loop (topology)
• Closed curve

Technology

• A closed feedback loop:
  • Closed-loop transfer function
  • Electronic feedback loop
  • PID controller
• Closed ecological system
• Closed-loop communication
• Ecological sanitation systems or ecosan

Other uses

• Circular economy, with materials recycled
• Closed time loop, a paradox of time travel
• Knot loop, in a knot

This disambiguation page lists articles associated with the title Closed loop.
If an internal link led you here, you may wish to change the link to point directly to the intended article.