Feedback is information about the operation returned at the core of the operation.

Feedback occurs when the output of the system is fed back as input to the part of the circuit that forms the circuit or loop. So we can say that the system reinvents itself. When implementing a feedback system, the concept of cause and effect should be carefully considered:

    A simple reason discussion of feedback systems is difficult is because the first system affects the second and the second system affects the first, leading to a circular calculation. This complicates the cause-and-effect debate and requires analysis of the entire system.
    - Carl Johann Ostrom and Richard M. Murray, Feedback systems: an introduction for researchers and engineers.