Editing Negative feedback (section)

{{Short description|Control concept}}
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[[Image:Ideal feedback model.svg|thumb | right | A simple negative feedback system is descriptive, for example, of some electronic amplifiers. The feedback is negative if the [[loop gain]] AB is negative.]] 

'''Negative feedback''' (or '''balancing feedback''') occurs when some [[function (Mathematics)|function]] of the output of a system, process, or mechanism is [[feedback|fed back]] in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances. 

Whereas [[positive feedback]] tends to instability via [[exponential growth]], [[oscillation]] or [[chaos theory|chaotic behavior]], negative feedback generally promotes stability. Negative feedback tends to promote a settling to [[List of types of equilibrium|equilibrium]], and reduces the effects of perturbations. Negative [[feedback loop]]s in which just the right amount of correction is applied with optimum timing, can be very stable, accurate, and responsive.

Negative feedback is widely used in [[Mechanical engineering|mechanical]] and [[electronic engineering]], and it is observed in many other fields including biology,<ref name=Ashby>
{{cite book |title=Introduction to cybernetics |chapter=Chapter 12: The error-controlled regulator |author=W. Ross Ashby |chapter-url=http://pcp.vub.ac.be/books/IntroCyb.pdf |pages=219–243 |year=1957 |publisher=Chapman & Hall Ltd.; Internet (1999)}} 
</ref><ref name=Ricklefs>{{cite book |title=Ecology |chapter=§6.1 Homeostasis depends upon negative feedback |chapter-url=https://books.google.com/books?id=6TMvdZQiySoC&pg=PA92 |page=92 |isbn=9780716728290 |year=2000 |publisher=Macmillan |author1=Robert E. Ricklefs |author2=Gary Leon Miller }}
</ref> chemistry and economics. General negative feedback systems are studied in [[Control engineering|control systems engineering]]. 

Negative feedback loops also play an integral role in maintaining the atmospheric balance in various climate systems on Earth. One such feedback system is the interaction between [[Solar irradiance|solar radiation]], [[cloud cover]], and planet temperature.

[[File:Negative Feedback Gif.gif|thumb|Blood glucose levels are maintained at a constant level in the body by a negative feedback mechanism. When the blood glucose level is too high, the pancreas secretes insulin and when the level is too low, the pancreas then secretes glucagon. The flat line shown represents the homeostatic set point. The sinusoidal line represents the blood glucose level.]]