feedback

feedback (ˈfiːdˌbæk)
—n
1.	a.  the return of part of the output of an electronic circuit, device, or mechanical system to its input, so modifying its characteristics. In negative feedback a rise in output energy reduces the input energy; in positive feedback an increase in output energy reinforces the input energy
	b.  that part of the output signal fed back into the input
2.	the return of part of the sound output by a loudspeaker to the microphone or pick-up so that a high-pitched whistle is produced
3.	the whistling noise so produced
4.	a.  the effect of the product of a biological pathway on the rate of an earlier step in that pathway
	b.  the substance or reaction causing such an effect, such as the release of a hormone in a biochemical pathway
5.	information in response to an inquiry, experiment, etc: there was little feedback from our questionnaire
—vb, —adv
6.	(tr) to return (part of the output of a system) to its input
7.	to offer or suggest (information, ideas, etc) in reaction to an inquiry, experiment, etc

feedback

feedback feed·back (fēd'bāk')
n.

1. The return of a portion of the output of a process or system to the input, especially when used to maintain performance or to control a system or process.

2. The portion of the output so returned.

3. The return of information about the result of a process or activity.

feedback   (fēd'bāk')  Pronunciation Key  The supply of an input to some process or system as a function of its output. See more at negative feedback, positive feedback.

feedback definition

A process in which a system regulates itself by monitoring its own output. That is, it “feeds back” part of its output to itself. Feedback is used to control machines; a heating system, for example, uses a thermostat to monitor and adjust its output. Feedback is also used by the human brain to control various muscles and joints.

Note: By extension, “feedback” is any response or information about the result of a process.

Note: Feedback is usually a feature of automation.

feedback definition

electronics
Part of a system output presented at its input. Feedback may be unintended. When used as a design feature, the output is usually transformed by passive components which attenuate it in some manner; the result is then presented at the system input.
Feedback is positive or negative, depending on the sign with which a positive change in the original input reappears after transformation. Negative feedback was invented by Black to stabilise vacuum tube amplifiers. The behaviour becomes largely a function of the feedback transformation and only minimally a function of factors such as transistor gain which are imperfectly known.
Positive feedback can lead to instability; it finds wide application in the construction of oscillators.
Feedback can be used to control a system, as in feedback control.
(1996-01-02)

feedback

in biology, a response within a system (molecule, cell, organism, or population) that influences the continued activity or productivity of that system. In essence, it is the control of a biological reaction by the end products of that reaction.

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