[feed-bak] 
| 1. | Electronics.
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| 2. | the furnishing of data concerning the operation or output of a machine to an automatic control device or to the machine itself, so that subsequent or ongoing operations of the machine can be altered or corrected. |
| 3. | a reaction or response to a particular process or activity: He got very little feedback from his speech. |
| 4. | evaluative information derived from such a reaction or response: to study the feedback from an audience survey. |
| 5. | Psychology. knowledge of the results of any behavior, considered as influencing or modifying further performance. Compare biofeedback. |
| 6. | Biology. a self-regulatory biological system, as in the synthesis of some hormones, in which the output or response affects the input, either positively or negatively. |
| (in an audio system, esp. a public-address system) the feedback of sound from a loudspeaker to a microphone, often resulting in a whistling noise caused by electrical oscillations. |
| feed·back (fēd'bāk') n.
|
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 feed·back (fēd'bāk')
n.
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.
The portion of the output so returned.
The return of information about the result of a process or activity.
feedback 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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