A process whereby a measurement of the output of a system is fed back as an input, which then affects subsequent outputs. The measured output of the system is compared to a desired set point, and any difference between the output and the set point is used to adjust the system’s inputs in order to reduce the difference. They are commonly used in control systems and can be either positive (reinforcing) or negative (dampening) depending on whether the output and input have the same or opposite effects on each other.
