Feedback in which the feedback signal is in phase with the input signal. Also called REGENERATIVE FEEDBACK.

See feedback system.

A feedback signal from the output that is added to the input signal.

refers to the process whereby a disturbance about a homeostatic set-point results in an increase in that disturbance. This form of feedback is rarely used in biological systems because of its explosive and damaging nature, but such a system operates in the generation of the upstroke of the action potential

feedback applied to a system in such a way that it tends to increase the output

feedback in phase with (augmenting) the input

Communication which involves telling someone about their good performance. Make this feedback timely, specific, and frequent.

Gives processes an unstable, runaway quality. When a perturbation occurs, it causes a result that amplifies the perturbation. This can lead to disaster (as in the runaway greenhouse effect). [See Chapter 8 of The Blind Watchmaker.

Acoustical interference in which the return signal has the same polarity as the input signal.

A process that results in an amplification of the response of a system to an external influence.  For example, increased atmospheric water vapor in response to global warming would be a positive feedback on warming, because water vapor is a GHG and thus increases in water vapor in association with increases in greenhouse gases would cause greater warming than would occur if water vapor remained constant.

the process by which the cause of a change is increased or amplified by its effect.

The return of a portion of the output signal to the input such that it is inphase with the input signal. A type of feedback in which the feedback signal is in phase with the amplifier input signal.

A feedback signal that is in phase with an amplifier input signal. Positive feedback is necessary for oscillation to occur.

A sequence of interactions that amplifies the response to an initial perturbation. The snow and ice albedo–temperature feedback is an example of a positive feedback. Compare negative feedback.

Positive feedback is a feedback system in which the system responds to the perturbation in the same direction as the perturbation (It is sometimes referred to as cumulative causation). In contrast, a system that responds to the perturbation in the opposite direction is called a negative feedback system. The term "positive" means responding to the same direction as the perturbation whereas "negative" means responding to the opposite direction.