440:
1792:
247:. This is caused by a phase shift around any loop. Due to these phase shifts the feedback signal of some frequencies can ultimately become in phase with the input signal and thus turn into positive feedback, creating a runaway condition. Even before the point where the phase shift becomes 180 degrees, stability of the negative feedback loop will become compromised, leading to increasing under- and overshoot following a disturbance. This problem is often dealt with by attenuating or changing the phase of the problematic frequencies in a design step called compensation. Unless the system naturally has sufficient damping, many negative feedback systems have
931:
457:
1335:
151:
1576:
479:
42:
137:
4385:
1850:
4397:
4409:
1514:
1815:, and planet temperature. As incoming solar radiation increases, planet temperature increases. As the temperature increases, the amount of plant life that can grow increases. This plant life can then make products such as sulfur which produce more cloud cover. An increase in cloud cover leads to higher
1962:
The concept of 'feedback', so simple and natural in certain elementary cases, becomes artificial and of little use when the interconnections between the parts become more complex...Such complex systems cannot be treated as an interlaced set of more or less independent feedback circuits, but only as a
1694:
If a mixture of the reactants and products exists at equilibrium in a sealed container and nitrogen gas is added to this system, then the equilibrium will shift toward the product side in response. If the temperature is raised, then the equilibrium will shift toward the reactant side which, since the
239:
is feedback in which the system responds so as to increase the magnitude of any particular perturbation, resulting in amplification of the original signal instead of stabilization. Any system in which there is positive feedback together with a gain greater than one will result in a runaway situation.
1654:. Glucocorticoids not only perform their respective functions throughout the body but also negatively affect the release of further stimulating secretions of both the hypothalamus and the pituitary gland, effectively reducing the output of glucocorticoids once a sufficient amount has been released.
140:
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.
1365:
The idealized model of an operational amplifier assumes that the gain is infinite, the input impedance is infinite, output resistance is zero, and input offset currents and voltages are zero. Such an ideal amplifier draws no current from the resistor divider. Ignoring dynamics (transient effects
68:
in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances. A classic example of negative feedback is a heating system thermostat — when the temperature gets high enough, the heater is turned OFF. When the temperature gets too
1489:
at low frequencies, decreasing gradually at higher frequencies. In addition, it exhibits a finite input impedance and a non-zero output impedance. Although practical op-amps are not ideal, the model of an ideal op-amp often suffices to understand circuit operation at low enough frequencies. As
1963:
whole. For understanding the general principles of dynamic systems, therefore, the concept of feedback is inadequate in itself. What is important is that complex systems, richly cross-connected internally, have complex behaviors, and that these behaviors can be goal-seeking in complex patterns.
2276:
In a simple feedback system a specific physical quantity is being controlled, and control is brought about by making an actual comparison of this quantity with its desired value and utilizing the difference to reduce the error observed. Such a system is self-correcting in the sense that any
158:
In many physical and biological systems, qualitatively different influences can oppose each other. For example, in biochemistry, one set of chemicals drives the system in a given direction, whereas another set of chemicals drives it in an opposing direction. If one or both of these opposing
1296:
770:
212:
refers to the sign of the multiplier in mathematical models for feedback. In delta notation, −Δoutput is added to or mixed into the input. In multivariate systems, vectors help to illustrate how several influences can both partially complement and partially oppose each other.
1614:
For hormone secretion regulated by the negative feedback loop: when gland X releases hormone X, this stimulates target cells to release hormone Y. When there is an excess of hormone Y, gland X "senses" this and inhibits its release of hormone X. As shown in the figure, most
1479:
1752:"There is a belief current in many countries and elevated to the rank of an official article of faith in the United States that free competition is itself a homeostatic process... Unfortunately the evidence, such as it is, is against this simple-minded theory."
76:— is when a trend is positively reinforced, creating amplification, such as the squealing "feedback" loop that can occur when a mic is brought too close to a speaker which is amplifying the very sounds the mic is picking up, or the runaway heating and ultimate
1370:), the infinite gain of the ideal op-amp means this feedback circuit drives the voltage difference between the two op-amp inputs to zero. Consequently, the voltage gain of the circuit in the diagram, assuming an ideal op amp, is the reciprocal of feedback
1361:
is extremely large, a small differential input signal would drive the output of the amplifier to one rail or the other in the absence of negative feedback. A simple example of the use of feedback is the op-amp voltage amplifier shown in the figure.
3275:
Jickells, T. D.; An, Z. S.; Andersen, K. K.; Baker, A. R.; Bergametti, G.; Brooks, N.; Cao, J. J.; Boyd, P. W.; Duce, R. A.; Hunter, K. A.; Kawahata, H. (2005). "Global Iron
Connections Between Desert Dust, Ocean Biogeochemistry, and Climate".
1908:
came up with the idea of using negative feedback in electronic amplifiers in 1927, submitted a patent application in 1928, and detailed its use in his paper of 1934, where he defined negative feedback as a type of coupling that
1020:
1957:
pointed out that, while it may clash with definitions that require a "materially evident" connection, "the exact definition of feedback is nowhere important". Ashby pointed out the limitations of the concept of "feedback":
2620:
267:(circa 1600) using expansion and contraction of columns of mercury in response to temperature changes were used in negative feedback systems to control vents in furnaces, maintaining a steady internal temperature.
1140:
596:). The regulator signal is derived from a weighted sum of the error signal, integral of the error signal, and derivative of the error signal. The weights of the respective components depend on the application.
1170:
1826:. As planet temperature increases, more water vapor is produced, creating more clouds. The clouds then block incoming solar radiation, lowering the temperature of the planet. This interaction produces less
605:
1380:
3649:
3035:
2805:
1846:
of
Alexandria in the 3rd century BCE. Self-regulating mechanisms have existed since antiquity, and were used to maintain a constant level in the reservoirs of water clocks as early as 200 BCE.
118:, and also within living organisms, and can be seen in many other fields from chemistry and economics to physical systems such as the climate. General negative feedback systems are studied in
2370:
Giannini, Alessandra; Biasutti, Michela; Verstraete, Michel M. (2008-12-01). "A climate model-based review of drought in the Sahel: Desertification, the re-greening and climate change".
1945:
helped to formalize the concepts of feedback control, defining feedback in general as "the chain of the transmission and return of information", and negative feedback as the case when:
546:
according to its interpretation of the error in the status of the system. This error may be introduced by a variety of possible disturbances or 'upsets', some slow and some rapid. The
1713:
Self-organization is the capability of certain systems "of organizing their own behavior or structure". There are many possible factors contributing to this capacity, and most often
3335:
Giannini, Alessandra; Biasutti, Michela; Verstraete, Michel M. (2008). "A climate model-based review of drought in the Sahel: Desertification, the re-greening and climate change".
1937:
All purposeful behavior may be considered to require negative feed-back. If a goal is to be attained, some signals from the goal are necessary at some time to direct the behavior.
871:
There are many advantages to feedback in amplifiers. In design, the type of feedback and amount of feedback are carefully selected to weigh and optimize these various benefits.
1153:
might arise from fluctuations in the amplifier output due to noise and nonlinearity (distortion) within this amplifier, or from other noise sources such as power supplies.
1490:
discussed in the previous section, the feedback circuit stabilizes the closed-loop gain and desensitizes the output to fluctuations generated inside the amplifier itself.
125:
Negative feedback loops also play an integral role in maintaining the atmospheric balance in various systems on Earth. One such feedback system is the interaction between
1904:
of an electronic amplifier. Friis and Jensen described this action as "positive feedback" and made passing mention of a contrasting "negative feed-back action" in 1924.
1743:, because mismatches between them feed back into the decision-making of suppliers and demanders of goods, altering prices and thereby reducing any discrepancy. However
1830:
and therefore less cloud cover. The cycle then repeats in a negative feedback loop. In this way, negative feedback loops in the environment have a stabilizing effect.
439:
835:
803:
1029:>> 1. This expression shows that a gain greater than one requires β < 1. Because the approximate gain 1/β is independent of the open-loop gain
3118:
Charlson, Robert J.; Lovelock, James E.; Andreae, Meinrat O.; Warren, Stephen G. (1987). "Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate".
1819:, or surface reflectivity, of the Earth. As albedo increases, however, the amount of solar radiation decreases. This, in turn, affects the rest of the cycle.
2591:
2778:
2824:
the forward path may not be strictly unilateral, the feedback path is usually bilateral, and the input and output coupling networks are often complicated.
955:
553:
In this framework, the physical form of a signal may undergo multiple transformations. For example, a change in weather may cause a disturbance to the
2927:
3105:
2660:
2647:
329:, minimises the effect of manufacturing variations in component parameters, and compensates for changes in characteristics due to temperature change.
883:
It increases circuit stability: that is, the gain remains stable though there are variations in ambient temperature, frequency and signal amplitude.
2749:
1893:
in 1868 described "component motions" associated with these governors that lead to a decrease in a disturbance or the amplitude of an oscillation.
2459:
2716:
1773:
1316:
and a unilateral feedback block has significant limitations. For methods of analysis that do not make these idealizations, see the article
1291:{\displaystyle {\text{Error signal}}=I-\beta O=I\left(1-\beta {\frac {O}{I}}\right)={\frac {I}{1+\beta A}}-{\frac {\beta D}{1+\beta A}}\ .}
863:
in 1927, and granted a patent in 1937 (US Patent 2,102,671) "a continuation of application Serial No. 298,155, filed August 8, 1928 ...").
1357:
Operational amplifier circuits typically employ negative feedback to get a predictable transfer function. Since the open-loop gain of an
1066:
224:
to refer to the reduction in difference between the desired and actual behavior of a system. In a psychology context, on the other hand,
765:{\displaystyle \mathrm {MV(t)} =K_{p}\left(\,{e(t)}+{\frac {1}{T_{i}}}\int _{0}^{t}{e(\tau )}\,{d\tau }+T_{d}{\frac {d}{dt}}e(t)\right)}
81:
1046:
3798:
289:(1788), negative feedback is used to maintain a near-constant speed of an engine, irrespective of the load or fuel-supply conditions.
1474:{\displaystyle V_{\text{out}}={\frac {R_{\text{1}}+R_{\text{2}}}{R_{\text{1}}}}V_{\text{in}}\!={\frac {1}{\beta }}V_{\text{in}}\,}
1037:(for example, due to manufacturing variations between units, or temperature effects upon components), provided only that the gain
2491:
1791:
4365:
1949:
The information fed back to the control center tends to oppose the departure of the controlled from the controlling quantity...
193:
and the physical, and biological sciences, common terms for the points around which the system gravitates include: attractors,
17:
1317:
45:
A simple negative feedback system is descriptive, for example, of some electronic amplifiers. The feedback is negative if the
3689:
1050:
1045:) is often called the 'desensitivity factor', and in the broader context of feedback effects that include other matters like
867:"The patent is 52 pages long plus 35 pages of figures. The first 43 pages amount to a small treatise on feedback amplifiers!"
3084:
1599:) use negative feedback. Examples of this are numerous, from the regulating of body temperature, to the regulating of blood
404:
in a constant phase to a reference signal. In many implementations the generated waveform is the output, but when used as a
3840:
111:
in which just the right amount of correction is applied with optimum timing, can be very stable, accurate, and responsive.
1757:
The notion of economic equilibrium being maintained in this fashion by market forces has also been questioned by numerous
4349:
2852:
1329:
296:(1866), power assistance is applied to the rudder with a feedback loop, to maintain the direction set by the steersman.
1338:
A feedback voltage amplifier using an op amp with finite gain but infinite input impedances and zero output impedance.
3746:
3716:
3597:
3449:
3020:
2987:
2943:
2910:
2878:
2817:
2788:
2761:
2732:
2699:
2670:
2632:
2603:
2574:
2328:
2300:
2246:
2196:
2145:
2115:
589:
provided by a furnace (an 'effector') to counter the initial weather-related disturbance in heat input to the house.
4178:
1312:
Although the diagram illustrates the principles of the negative feedback amplifier, modeling a real amplifier as a
542:) to reduce the gap between the measurement and the required value. The regulator modifies the input to the system
390:
904:
4413:
1639:
1607:, if negative feedback fails, the glucose levels in the blood may begin to rise dramatically, thus resulting in
4339:
69:
cold, the heat is turned back ON. In each case the "feedback" generated by the thermostat "negates" the trend.
1164:
at the amplifier input is sometimes called the "error signal". According to the diagram, the error signal is:
4344:
3791:
578:
535:
1953:
While the view of feedback as any "circularity of action" helped to keep the theory simple and consistent,
550:
in such systems can range from a simple 'on-off' control to a more complex processing of the error signal.
379:
104:
3099:
2687:
1145:
which shows that the feedback reduces the effect of the disturbance by the 'improvement factor' (1+β
592:
Error controlled regulation is typically carried out using a
Proportional-Integral-Derivative Controller (
3537:
3003:
Scott
Camazine; Jean-Louis Deneubourg; Nigel R Franks; James Sneyd; Guy Theraulaz; Eric Bonabeau (2003).
2025:
1933:
subsequently generalized the idea of negative feedback to cover any goal-seeking or purposeful behavior.
1667:
943:
920:
850:
547:
375:
2208:
Herold, David M.; Greller, Martin M. (1977). "Research Notes. Feedback: The
Definition of a Construct".
4445:
4193:
4045:
274:
metaphor of economic theory (1776), reactions to price movements provide a feedback mechanism to match
3635:
2470:
2037:
1807:
A basic and common example of a negative feedback system in the environment is the interaction among
1796:
1566:
531:
198:
3392:
2435:
4450:
4389:
3784:
103:, negative feedback generally promotes stability. Negative feedback tends to promote a settling to
3765:
2345:
412:
radio receiver, the error feedback voltage serves as the demodulated output signal. If there is a
4435:
2862:
2016:
1729:
are government programs that are intended to work as negative feedback to dampen fluctuations in
4073:
1674:
to the opposite side of the reaction in order to reduce a stress. For example, in the reaction
4401:
4093:
3896:
3387:
2430:
1920:
1342:
The operational amplifier was originally developed as a building block for the construction of
930:
372:
341:
337:
179:
115:
61:
3653:. Cambridge, Massachusetts: The Technology Press; New York: John Wiley & Sons, Inc., 1948.
2898:
2558:
2290:
1545:. Similar control mechanisms are used in heating and cooling systems, such as those involving
4370:
4083:
3953:
3581:
3004:
2973:
2318:
2103:
1993:
1358:
1313:
31:
3002:
2271:
2236:
4440:
4233:
4208:
4163:
4011:
4006:
3968:
3943:
3344:
3285:
3231:
3182:
3127:
2422:
2379:
2031:
1916:
1905:
1901:
1870:
1854:
1769:
1736:
1726:
1671:
856:
813:
781:
417:
286:
229:
1913:
the gain of the amplifier, in the process greatly increasing its stability and bandwidth.
1717:
is identified as a possible contributor. However, negative feedback also can play a role.
8:
4108:
4001:
2049:
1890:
1758:
1663:
1603:
levels. The disruption of feedback loops can lead to undesirable results: in the case of
1508:
934:
Negative feedback amplifier with external disturbance. The feedback is negative if β
465:
311:, is compared to a set value, and any error is reduced by negative feedback to the input.
119:
3678:
3348:
3289:
3235:
3186:
3171:"Amplified Arctic climate change: What does surface albedo feedback have to do with it?"
3131:
2426:
2383:
4238:
4173:
4153:
4143:
4103:
4088:
4063:
4021:
4016:
3870:
3860:
3855:
3556:
3522:
3491:
3317:
3257:
3151:
2217:
1954:
1530:
322:
275:
92:
2514:
4455:
4396:
4303:
4218:
4158:
4128:
4053:
3911:
3830:
3742:
3712:
3685:
3593:
3445:
3360:
3309:
3301:
3249:
3200:
3143:
3016:
2983:
2939:
2906:
2874:
2848:
2813:
2784:
2757:
2728:
2695:
2666:
2628:
2599:
2570:
2395:
2324:
2296:
2264:
2242:
2192:
2141:
2111:
2043:
1862:
1800:
1740:
1714:
1704:
1608:
1604:
1534:
1367:
916:
860:
413:
397:
236:
88:
73:
3495:
3356:
3321:
3261:
2391:
2137:
Between Human and
Machine : Feedback, Control, and Computing before Cybernetics
1334:
4298:
4168:
4030:
3981:
3963:
3552:
3518:
3481:
3397:
3352:
3293:
3239:
3190:
3155:
3135:
2539:
2506:
2440:
2387:
2170:
1926:
Nyquist and Bode built on Black's work to develop a theory of amplifier stability.
1812:
1546:
1343:
1301:
From this expression, it can be seen that a large 'improvement factor' (or a large
1015:{\displaystyle {\frac {O}{I}}={\frac {A}{1+\beta A}}\approx {\frac {1}{\beta }}\ ,}
892:
Harmonic, phase, amplitude, and frequency distortions are all reduced considerably.
519:
518:). Using a negative feedback loop, a measurement of some variable (for example, a
456:
333:
194:
126:
77:
3708:
Science and Policy in
Natural Resource Management: Understanding System Complexity
1822:
Cloud cover, and in turn planet albedo and temperature, is also influenced by the
4268:
4253:
4228:
4203:
4123:
4118:
4078:
3996:
3991:
3986:
3901:
3850:
3807:
3736:
3706:
3439:
3401:
3076:
3063:
3049:
2842:
2413:
Bechhoefer, John (2005). "Feedback for
Physicists: A Tutorial Essay On Control".
2135:
1643:
1504:
1371:
1351:
927:
that identify stable feedback systems, including amplifiers and control systems.
409:
293:
248:
217:
2316:
1650:. In turn, ACTH directs the adrenal cortex to secrete glucocorticoids, such as
569:). This quantity, then, is converted by the thermostat (a 'comparator') into an
4323:
4318:
4313:
4283:
4258:
4248:
4243:
4213:
4138:
4133:
4098:
4058:
4026:
3948:
3933:
3865:
3835:
3615:"Karl Kupfmuller, 1928: an early time-domain, closed-loop, stability criterion"
2975:
Psychomythics: Sources of
Artifacts and Misconceptions in Scientific Psychology
2510:
2013: – Transdisciplinary field concerned with regulatory and purposive systems
2004:
1942:
1866:
1838:
Negative feedback as a control technique may be seen in the refinements of the
1744:
1631:
1627:
1592:
1588:
1538:
593:
386:
300:
271:
264:
205:
2444:
2277:
deviations from the desired performance are used to produce corrective action.
1521:
or float valve uses negative feedback to control the water level in a cistern.
1033:, the feedback is said to 'desensitize' the closed-loop gain to variations in
416:
between the generated waveform and the phase comparator, the device acts as a
150:
4429:
4308:
4223:
4183:
4068:
3891:
3875:
3364:
3305:
3253:
3204:
3147:
2873:(The Circuits and Filters Handbook, 3rd ed.). CRC Press. pp. 16–2.
2543:
2399:
2054:
1596:
1550:
912:
534:) to estimate an operational error in system status, which is then used by a
383:
108:
35:
3614:
3297:
1967:
To reduce confusion, later authors have suggested alternative terms such as
1346:, but is now used almost universally in all kinds of applications including
4288:
4188:
4113:
3486:
3313:
2028: – Graphical method of determining the stability of a dynamical system
1886:
1765:
1635:
1347:
924:
899:
Though negative feedback has many advantages, amplifiers with feedback can
167:
100:
2174:
2081:
478:
232:
of the feedback – attractive versus aversive, or praise versus criticism.
4278:
4273:
4263:
4198:
3938:
3825:
3378:
Breedveld, Peter C (2004). "Port-based modeling of mechatronic systems".
3195:
3170:
2010:
1998:
1930:
1839:
1827:
1823:
1808:
1776:
1575:
1570:
1542:
908:
527:
511:
469:
432:
428:
405:
349:
244:
190:
186:
171:
130:
96:
3244:
3219:
2057: – Time behavior of a system controlled by Heaviside step functions
1695:
reverse reaction is endothermic, will partially reduce the temperature.
240:
Both positive and negative feedback require a feedback loop to operate.
136:
4293:
4148:
3680:
The Fifth
Discipline: The Art and Practice of the Learning Organization
3650:
Cybernetics: Or Control and Communication in the Animal and the Machine
3466:
3036:
Cybernetics: Or Control and Communication in the Animal and the Machine
1882:
1849:
1780:
1623:
1584:
949:
The feedback sets the overall (closed-loop) amplifier gain at a value:
473:
357:
326:
318:
41:
2221:
389:), a negative feedback loop is used to repeatedly correct accumulated
3958:
3845:
3139:
2234:
1874:
1843:
1762:
1708:
1616:
1302:
900:
424:
361:
175:
46:
3415:
2189:
Business Dynamics: Systems Thinking and Modeling for a Complex World
3104:
Sixth Assessment Report (AR6), Working Group I, IPCC, 2021, p. 96.
1897:
1878:
1730:
1651:
1554:
1526:
1518:
1135:{\displaystyle O={\frac {AI}{1+\beta A}}+{\frac {D}{1+\beta A}}\ ,}
401:
353:
345:
65:
3776:
2101:
880:
It reduces non-linear distortion, that is, it has higher fidelity.
3509:
Friis, H. T.; Jensen, A. G. (1924). "High Frequency Amplifiers".
2844:
Design with operational amplifiers and analog integrated circuits
2592:"Figure 11-4: Classical single input, single output control loop"
1619:
1600:
365:
252:
163:
3704:
1900:" was well established by the 1920s, in reference to a means of
1885:
patented a form of governor in 1788 to control the speed of his
3815:
1816:
427:, feedback enables various measures (e.g. body temperature, or
308:
279:
2962:, Fifth Edition, Boston: Hill Companies, Inc. 1999. page 1058.
2534:
CA Desoer (August 1984). "In Memoriam: Harold Stephen Black".
1583:
Some biological systems exhibit negative feedback such as the
1533:. In modern engineering, negative feedback loops are found in
498:
that result in the desired system output despite disturbances
3723:
Balancing or negative feedback counteracts and opposes change
3416:"Tierie, Gerrit. Cornelis Drebbel. Amsterdam: HJ Paris, 1932"
3117:
2317:
William Y. Svrcek; Donald P. Mahoney; Brent R. Young (2013).
2161:
Arkalgud Ramaprasad (1983). "On The Definition of Feedback".
2091:. Chapman & Hall Ltd.; Internet (1999). pp. 219–243.
400:(1932), feedback is used to maintain a generated alternating
315:
304:
2046: – Feedback loop that increases an initial small effect
1739:
asserts that the market pricing mechanism operates to match
1041:
is sufficiently large. In this context, the factor (1+β
197:
states, eigenstates/eigenfunctions, equilibrium points, and
30:
For use of criticism and punishment to modify behavior, see
2860:
2034: – Control system whose input is independent of output
1647:
1513:
243:
However, negative feedback systems can still be subject to
3634:
Rosenblueth, Arturo, Norbert Wiener, and Julian Bigelow. "
3334:
3220:"Cloud Feedbacks in the Climate System: A Critical Review"
2369:
1923:
system and a feedback system stability criterion in 1928.
1525:
An example of the use of negative feedback control is the
2665:(2nd ed.). Cambridge University Press. p. 447.
2625:
Basic Electronics: Devices, Circuits, and IT Fundamentals
2563:
Basic electronics: Devices, circuits and its fundamentals
1873:
were used to regulate the distance and pressure between
585:
control valves and an ignitor) ultimately to change the
159:
influences are non-linear, equilibrium point(s) result.
3582:"Chapter 3: The electronic negative feedback amplifier"
3274:
2754:
Linear Control Systems: For Punjab Technical University
2021:
Pages displaying short descriptions of redirect targets
1861:
Negative feedback was implemented in the 17th century.
141:
The sinusoidal line represents the blood glucose level.
3735:
Carver, Charles S.; Scheier, Michael F. (2001-05-07).
2899:"§6.3.4 Linear amplifiers with operational amplifiers"
2140:. Baltimore, MD, USA: Johns Hopkins University Press.
1666:
can also exhibit negative feedback in accordance with
216:
Some authors, in particular with respect to modelling
3091:
3069:
2896:
2492:"Electrical engineering hall of fame: Harold S Black"
1383:
1173:
1069:
958:
875:
Advantages of negative voltage feedback in amplifiers
816:
784:
608:
107:, and reduces the effects of perturbations. Negative
561:) that is monitored by a thermometer as a change in
64:
of the output of a system, process, or mechanism is
3588:. Institution of Electrical Engineers. pp. 70
2692:
Electronic Circuits: Analysis simulation and design
2323:(3rd ed.). John Wiley & Sons. p. 57.
2292:
Process Control: Concepts Dynamics And Applications
2160:
1579:
Control of endocrine hormones by negative feedback.
114:Negative feedback is widely used in mechanical and
3677:
2263:
1662:Closed systems containing substances undergoing a
1473:
1290:
1134:
1014:
829:
797:
764:
599:Mathematically, the regulator signal is given by:
431:level) to be maintained within a desired range by
3770:biology online: answers to your biology questions
2750:"§5.3.3 Effect of feedback on disturbance signal"
2559:"§6.3 Advantages of negative feedback amplifiers"
2104:"§6.1 Homeostasis depends upon negative feedback"
2001: – Gaining awareness of biological processes
1446:
1323:
942:The figure shows a simplified block diagram of a
4427:
2971:
2489:
2460:"U.S. Patent 2,102,671: Wave Translation System"
2343:
2261:
2235:Sudheer S Bhagade; Govind Das Nageshwar (2011).
2133:
1803:) or weaken (negative feedbacks) global warming.
855:The negative feedback amplifier was invented by
2783:(2nd ed.). Cengage Learning. p. 642.
2780:Microelectronic Circuits: Analysis & Design
2776:
2685:
1626:negative feedback inhibition loop, such as the
3675:
3579:
2810:Circuit Analysis and Feedback Amplifier Theory
2315:For example, input and load disturbances. See
1919:published papers on a negative-feedback-based
844:
557:input to a house (as an example of the system
451:
3792:
3734:
2925:
2840:
2741:
2352:. University of Exeter: Physics and astronomy
2207:
2102:Robert E. Ricklefs; Gary Leon Miller (2000).
2079:
2007: – Branch of engineering and mathematics
1869:incubators and ovens in the early 1600s, and
514:to minimize the effect of a disturbance (say
506:One use of feedback is to make a system (say
307:or position of an output, as determined by a
3638:." Philosophy of science 10.1 (1943): 18-24.
3077:"The Study of Earth as an Integrated System"
2803:
2714:
2658:
2618:
2589:
2556:
2082:"Chapter 12: The error-controlled regulator"
889:It modifies the input and output impedances.
573:error in status compared to the 'set point'
3711:. Cambridge University Press. p. 205.
3705:Helen E. Allison; Richard J. Hobbs (2006).
3628:
3575:
3573:
3508:
2903:The Design of High Performance Mechatronics
2892:
2890:
2747:
2662:The Design of CMOS Radio Frequency Circuits
2627:. PHI Learning Pvt. Ltd. pp. 193–194.
2485:
2483:
1529:control of water level (see diagram), or a
1060:is included, the amplifier output becomes:
446:
3799:
3785:
3612:
3586:A history of control engineering 1930-1955
3474:Proceedings of the Royal Society of London
3011:. Princeton University Press. pp. 15
2412:
2406:
2019: – Feedback related to climate change
1595:. Many biological processes (e.g., in the
1025:where the approximate value assumes β
565:(as an example of an 'essential variable'
80:of a nuclear reactor which has a positive
3485:
3391:
3377:
3243:
3194:
2721:Basic Electronics: Devices, Circuits and
2641:
2533:
2529:
2527:
2434:
2201:
2154:
2129:
2127:
1857:is an early example of negative feedback.
1498:
1485:A real op-amp has a high but finite gain
1470:
1309:) tends to keep this error signal small.
708:
644:
581:(containing a 'controller' that commands
3570:
3217:
3005:"Chapter 2: How self-organization works"
2996:
2887:
2583:
2480:
2288:
2241:. PHI Learning Pvt. Ltd. pp. 6, 9.
1848:
1790:
1786:
1574:
1512:
1333:
929:
477:
455:
438:
149:
135:
40:
3664:Circuit Theory of Linear Noisy Networks
3464:
3458:
3380:Mathematics and Computers in Simulation
3009:Self-organization in biological systems
2865:The four possible op-amp configurations
2320:A Real-Time Approach to Process Control
2095:
2075:
2073:
2071:
1493:
14:
4428:
3772:. Biology-Online.org. 30 January 2020.
3728:
3641:
3339:. Climate Change and Desertification.
3168:
3087:from the original on November 2, 2016.
2861:David G Nair; Sergio B Franco (2009).
2829:
2770:
2565:. PHI Learning Pvt. Ltd. pp. 193
2536:IEEE Transactions on Automatic Control
2524:
2374:. Climate Change and Desertification.
2337:
2309:
2295:. PHI Learning Pvt. Ltd. p. 222.
2228:
2181:
2124:
1314:unilateral forward amplification block
145:
3780:
3698:
3669:
3662:Hermann A Haus and Richard B. Adler,
3535:
3529:
3502:
3437:
2965:
2806:"Chapter 13: General feedback theory"
2679:
2457:
1640:corticotropin-releasing hormone (CRH)
490:so the monitored essential variables
460:Basic error-controlled regulator loop
82:temperature coefficient of reactivity
27:Reuse of output to stabilize a system
4408:
3684:. New York: Doubleday. p. 424.
2919:
2871:Fundamentals of Circuits and Filters
2797:
2708:
2612:
2550:
2282:
2255:
2068:
1698:
4350:Systems theory in political science
3806:
3108:from the original on July 21, 2022.
2835:See, for example, Figure 1.4, p. 7
2652:
24:
3738:On the Self-Regulation of Behavior
3557:10.1002/j.1538-7305.1934.tb00652.x
3523:10.1002/j.1538-7305.1924.tb01354.x
2490:James E Brittain (February 2011).
2270:. Addison-Wesley Pub. Co. p.
1648:adrenocorticotropic hormone (ACTH)
1330:Operational amplifier applications
619:
613:
610:
25:
4467:
3758:
2727:. PHI Learning Pvt. p. 194.
1929:Early researchers in the area of
91:tends to lead to instability via
4407:
4395:
4384:
4383:
3538:"Stabilized Feedback Amplifiers"
2978:. Psychology Press. pp. 95
2897:G. Schitter; A. Rankers (2014).
2715:Santiram Kal (14 January 2009).
2350:Feedback and temperature control
886:It increases bandwidth slightly.
154:Feedback loops in the human body
3656:
3636:Behavior, purpose and teleology
3606:
3431:
3408:
3371:
3357:10.1016/j.gloplacha.2008.05.004
3328:
3268:
3211:
3162:
3111:
3055:
3041:
3029:
2952:
2596:Intuitive Analog Circuit Design
2451:
2392:10.1016/j.gloplacha.2008.05.004
2363:
577:, and subsequently used by the
72:The opposite tendency — called
4340:Systems theory in anthropology
3741:. Cambridge University Press.
3444:. Cambridge University Press.
2694:. Prentice Hall. p. 671.
2266:Principles of Feedback Control
1324:Operational amplifier circuits
895:Noise is reduced considerably.
754:
748:
704:
698:
655:
649:
622:
616:
486:adjusts the input to a system
13:
1:
4345:Systems theory in archaeology
3622:IEEE Control Systems Magazine
3511:Bell System Technical Journal
3465:Maxwell, James Clerk (1868).
2847:(3rd ed.). McGraw-Hill.
2210:Academy of Management Journal
2062:
494:are held to set-point values
321:, negative feedback flattens
3536:Black, H.S. (January 1934).
3402:10.1016/j.matcom.2003.11.002
3218:Stephens, Graeme L. (2005).
3175:Geophysical Research Letters
2932:Op Amp Applications Handbook
2812:. CRC Press. pp. 13–1.
2458:Black, Harold (1937-12-21).
2238:Process Dynamics and Control
2040: – Psychological theory
1720:
1664:reversible chemical reaction
1657:
1053:, the 'improvement factor'.
380:digital-to-analog converters
272:invisible hand of the market
166:, this process (in general,
7:
3766:"Physiological Homeostasis"
3337:Global and Planetary Change
2756:. Pearson Education India.
2372:Global and Planetary Change
2346:"Types of feedback control"
2089:Introduction to cybernetics
2026:Nyquist stability criterion
1986:
1867:thermostatically controlled
1318:Negative feedback amplifier
944:negative feedback amplifier
921:Nyquist stability criterion
851:Negative feedback amplifier
845:Negative feedback amplifier
530:from a required value (the
452:Error-controlled regulation
258:
120:control systems engineering
10:
4472:
2905:. IOS Press. p. 499.
2511:10.1109/jproc.2010.2090997
1833:
1702:
1564:
1560:
1502:
1327:
848:
463:
178:, the more common term is
170:) is often referred to as
133:, and planet temperature.
29:
4379:
4358:
4332:
4044:
3977:
3929:
3920:
3884:
3841:Coupled human–environment
3814:
3438:Hills, Richard L (1996).
2972:William R. Uttal (2014).
2869:. In Wai-Kai Chen (ed.).
2445:10.1103/revmodphys.77.783
2415:Reviews of Modern Physics
2262:Charles H. Wilts (1960).
2191:McGraw Hill/Irwin, 2000.
2134:David A. Mindell (2002).
2110:. Macmillan. p. 92.
2038:Perceptual control theory
1797:effects of climate change
1567:Counterregulatory hormone
3169:Winton, Michael (2006).
2958:Raven, PH; Johnson, GB.
2777:Muhammad Rashid (2010).
2717:"§6.3.2 Noise Reduction"
2686:Norbert A Malik (1995).
2544:10.1109/tac.1984.1103645
1983:in place of "negative".
1668:Le Chatelier's principle
1644:anterior pituitary gland
907:. They may even exhibit
447:Detailed implementations
4174:Charles A. S. Hall
3676:Peter M. Senge (1990).
3580:Stuart Bennett (1993).
3298:10.1126/science.1105959
2648:Marc T Thompson, p. 309
2621:"§6.3.1 Gain stability"
2499:Proceedings of the IEEE
2017:Climate change feedback
382:(particularly for high
4094:Ludwig von Bertalanffy
3498:– via Wikimedia.
3487:10.1098/rspl.1867.0055
3064:Steady State Economics
3050:The Alchemy of Finance
2934:. Newnes. pp. 12
2926:Walter G Jung (2005).
2841:Sergio Franco (2002).
2538:. AC-29 (8): 673–674.
2344:Charles D H Williams.
2080:W. Ross Ashby (1957).
1965:
1951:
1939:
1921:automatic gain control
1858:
1804:
1580:
1522:
1499:Mechanical engineering
1475:
1339:
1292:
1156:The difference signal
1136:
1016:
939:
831:
799:
766:
503:
461:
443:
342:mathematical functions
338:operational amplifiers
155:
142:
116:electronic engineering
50:
18:Negative feedback loop
4371:Principia Cybernetica
4084:Anthony Stafford Beer
3954:Sociotechnical system
2804:Wai-Kai Chen (2005).
2659:Thomas H Lee (2004).
2619:Santiram Kal (2009).
2590:Marc Thomson (2006).
2557:Santiram Kal (2009).
2520:on November 29, 2014.
2175:10.1002/bs.3830280103
1994:Asymptotic gain model
1960:
1947:
1935:
1871:centrifugal governors
1852:
1794:
1787:Environmental Science
1774:steady-state theorist
1727:automatic stabilisers
1578:
1516:
1476:
1337:
1293:
1137:
1017:
933:
903:. See the article on
832:
830:{\displaystyle T_{d}}
800:
798:{\displaystyle T_{i}}
767:
481:
459:
442:
287:centrifugal governors
153:
139:
44:
32:performance appraisal
4234:Mihajlo D. Mesarovic
4209:Edward Norton Lorenz
4164:Jay Wright Forrester
3969:World-systems theory
3944:Earth system science
3196:10.1029/2005GL025244
2688:"Improvement Factor"
2032:Open-loop controller
1981:discrepancy-reducing
1941:Cybernetics pioneer
1906:Harold Stephen Black
1799:can either enhance (
1770:ecological economist
1737:Mainstream economics
1672:chemical equilibrium
1642:, which directs the
1622:are controlled by a
1605:blood glucose levels
1494:Areas of application
1381:
1171:
1067:
1047:electrical impedance
956:
857:Harold Stephen Black
814:
782:
606:
418:frequency multiplier
340:is used to generate
4109:Kenneth E. Boulding
3613:C. Bissell (2006).
3545:Bell System Tech. J
3441:Power From the Wind
3349:2008GPC....64..119G
3290:2005Sci...308...67J
3245:10.1175/JCLI-3243.1
3236:2005JCli...18..237S
3187:2006GeoRL..33.3701W
3132:1987Natur.326..655C
2427:2005RvMP...77..783B
2384:2008GPC....64..119G
2050:Stability criterion
1891:James Clerk Maxwell
1779:, who was with the
1761:economists such as
1509:Control engineering
1149:). The disturbance
1056:If the disturbance
693:
466:Control engineering
265:Mercury thermostats
146:General description
60:) occurs when some
4239:James Grier Miller
4194:Faina M. Kirillova
4154:Heinz von Foerster
4144:Edsger W. Dijkstra
4104:Alexander Bogdanov
4089:Richard E. Bellman
4064:William Ross Ashby
3224:Journal of Climate
2837:Ideal op amp model
2163:Behavioral Science
1859:
1824:hydrological cycle
1805:
1801:positive feedbacks
1581:
1531:pressure regulator
1523:
1471:
1340:
1288:
1132:
1012:
940:
827:
795:
762:
679:
504:
462:
444:
393:during conversion.
391:quantization error
336:, feedback around
323:frequency response
156:
143:
93:exponential growth
58:balancing feedback
51:
4446:Signal processing
4423:
4422:
4304:Manuela M. Veloso
4219:Humberto Maturana
4159:Stephanie Forrest
4129:C. West Churchman
4054:Russell L. Ackoff
4040:
4039:
3912:Positive feedback
3907:Negative feedback
3691:978-0-385-26094-7
3666:, MIT Press, 1959
3126:(6114): 655–661.
3100:Technical Summary
2928:"Noise gain (NG)"
2748:SK Bhattacharya.
2467:www.eepatents.com
2289:SK Singh (2010).
2044:Positive feedback
1902:boosting the gain
1863:Cornelius Drebbel
1855:fly-ball governor
1741:supply and demand
1715:positive feedback
1705:Self-organization
1699:Self-organization
1467:
1458:
1443:
1434:
1431:
1420:
1407:
1391:
1368:propagation delay
1284:
1280:
1251:
1222:
1177:
1128:
1124:
1100:
1008:
1004:
991:
967:
917:Bell Laboratories
861:Bell Laboratories
743:
677:
414:frequency divider
398:phase locked loop
376:analog-to-digital
237:positive feedback
89:positive feedback
74:positive feedback
54:Negative feedback
16:(Redirected from
4463:
4411:
4410:
4399:
4387:
4386:
4299:Francisco Varela
4031:Systems thinking
3964:Urban metabolism
3927:
3926:
3801:
3794:
3787:
3778:
3777:
3773:
3753:
3752:
3732:
3726:
3725:
3702:
3696:
3695:
3683:
3673:
3667:
3660:
3654:
3645:
3639:
3632:
3626:
3625:
3619:
3610:
3604:
3603:
3577:
3568:
3567:
3565:
3563:
3542:
3533:
3527:
3526:
3506:
3500:
3499:
3489:
3471:
3462:
3456:
3455:
3435:
3429:
3428:
3426:
3425:
3420:
3412:
3406:
3405:
3395:
3375:
3369:
3368:
3332:
3326:
3325:
3272:
3266:
3265:
3247:
3215:
3209:
3208:
3198:
3166:
3160:
3159:
3140:10.1038/326655a0
3115:
3109:
3095:
3089:
3088:
3073:
3067:
3059:
3053:
3045:
3039:
3033:
3027:
3026:
3000:
2994:
2993:
2969:
2963:
2956:
2950:
2949:
2923:
2917:
2916:
2894:
2885:
2884:
2858:
2833:
2827:
2826:
2801:
2795:
2794:
2774:
2768:
2767:
2745:
2739:
2738:
2712:
2706:
2705:
2683:
2677:
2676:
2656:
2650:
2645:
2639:
2638:
2616:
2610:
2609:
2587:
2581:
2580:
2554:
2548:
2547:
2531:
2522:
2521:
2519:
2513:. Archived from
2496:
2487:
2478:
2477:
2475:
2469:. Archived from
2464:
2455:
2449:
2448:
2438:
2410:
2404:
2403:
2367:
2361:
2360:
2358:
2357:
2341:
2335:
2334:
2313:
2307:
2306:
2286:
2280:
2279:
2269:
2259:
2253:
2252:
2232:
2226:
2225:
2205:
2199:
2187:John D.Sterman,
2185:
2179:
2178:
2158:
2152:
2151:
2131:
2122:
2121:
2099:
2093:
2092:
2086:
2077:
2022:
1811:, plant growth,
1670:which shift the
1630:secreted by the
1547:air conditioners
1535:engine governors
1480:
1478:
1477:
1472:
1469:
1468:
1465:
1459:
1451:
1445:
1444:
1441:
1435:
1433:
1432:
1429:
1423:
1422:
1421:
1418:
1409:
1408:
1405:
1398:
1393:
1392:
1389:
1372:voltage division
1344:analog computers
1297:
1295:
1294:
1289:
1282:
1281:
1279:
1265:
1257:
1252:
1250:
1233:
1228:
1224:
1223:
1215:
1178:
1175:
1141:
1139:
1138:
1133:
1126:
1125:
1123:
1106:
1101:
1099:
1085:
1077:
1021:
1019:
1018:
1013:
1006:
1005:
997:
992:
990:
973:
968:
960:
836:
834:
833:
828:
826:
825:
804:
802:
801:
796:
794:
793:
771:
769:
768:
763:
761:
757:
744:
742:
731:
729:
728:
716:
707:
692:
687:
678:
676:
675:
663:
658:
638:
637:
625:
520:process variable
334:analog computing
249:low pass filters
218:business systems
101:chaotic behavior
21:
4471:
4470:
4466:
4465:
4464:
4462:
4461:
4460:
4451:Analog circuits
4426:
4425:
4424:
4419:
4375:
4354:
4328:
4269:Anatol Rapoport
4254:Talcott Parsons
4229:Donella Meadows
4204:Allenna Leonard
4124:Mary Cartwright
4119:Kathleen Carley
4079:Gregory Bateson
4074:Béla H. Bánáthy
4036:
3973:
3922:
3916:
3902:Limiting factor
3897:Leverage points
3880:
3818:
3810:
3808:Systems science
3805:
3764:
3761:
3756:
3749:
3733:
3729:
3719:
3703:
3699:
3692:
3674:
3670:
3661:
3657:
3647:Norbert Wiener
3646:
3642:
3633:
3629:
3624:: 115–116, 126.
3617:
3611:
3607:
3600:
3578:
3571:
3561:
3559:
3540:
3534:
3530:
3507:
3503:
3469:
3463:
3459:
3452:
3436:
3432:
3423:
3421:
3418:
3414:
3413:
3409:
3393:10.1.1.108.9830
3376:
3372:
3333:
3329:
3284:(5718): 67–71.
3273:
3269:
3216:
3212:
3167:
3163:
3116:
3112:
3096:
3092:
3075:
3074:
3070:
3060:
3056:
3047:Goeroge Soros,
3046:
3042:
3034:
3030:
3023:
3001:
2997:
2990:
2970:
2966:
2957:
2953:
2946:
2924:
2920:
2913:
2895:
2888:
2881:
2855:
2834:
2830:
2820:
2802:
2798:
2791:
2775:
2771:
2764:
2746:
2742:
2735:
2713:
2709:
2702:
2684:
2680:
2673:
2657:
2653:
2646:
2642:
2635:
2617:
2613:
2606:
2588:
2584:
2577:
2555:
2551:
2532:
2525:
2517:
2494:
2488:
2481:
2473:
2462:
2456:
2452:
2436:10.1.1.124.7043
2411:
2407:
2368:
2364:
2355:
2353:
2342:
2338:
2331:
2314:
2310:
2303:
2287:
2283:
2260:
2256:
2249:
2233:
2229:
2206:
2202:
2186:
2182:
2159:
2155:
2148:
2132:
2125:
2118:
2100:
2096:
2084:
2078:
2069:
2065:
2060:
2020:
1989:
1973:self-correcting
1917:Karl Küpfmüller
1836:
1813:solar radiation
1789:
1747:wrote in 1948:
1723:
1711:
1703:Main articles:
1701:
1689:
1685:
1681:
1660:
1628:glucocorticoids
1591:regulation and
1573:
1563:
1511:
1505:Control systems
1501:
1496:
1464:
1460:
1450:
1440:
1436:
1428:
1424:
1417:
1413:
1404:
1400:
1399:
1397:
1388:
1384:
1382:
1379:
1378:
1352:control systems
1332:
1326:
1266:
1258:
1256:
1237:
1232:
1214:
1204:
1200:
1174:
1172:
1169:
1168:
1110:
1105:
1086:
1078:
1076:
1068:
1065:
1064:
996:
977:
972:
959:
957:
954:
953:
853:
847:
839:derivative time
821:
817:
815:
812:
811:
789:
785:
783:
780:
779:
735:
730:
724:
720:
709:
694:
688:
683:
671:
667:
662:
645:
643:
639:
633:
629:
609:
607:
604:
603:
512:self-regulating
476:
454:
449:
358:differentiation
301:servomechanisms
294:steering engine
261:
148:
127:solar radiation
49:AB is negative.
39:
28:
23:
22:
15:
12:
11:
5:
4469:
4459:
4458:
4453:
4448:
4443:
4438:
4436:Control theory
4421:
4420:
4418:
4417:
4405:
4393:
4380:
4377:
4376:
4374:
4373:
4368:
4362:
4360:
4356:
4355:
4353:
4352:
4347:
4342:
4336:
4334:
4330:
4329:
4327:
4326:
4324:Anthony Wilden
4321:
4319:Jennifer Wilby
4316:
4314:Norbert Wiener
4311:
4306:
4301:
4296:
4291:
4286:
4284:Claude Shannon
4281:
4276:
4271:
4266:
4261:
4259:Ilya Prigogine
4256:
4251:
4249:Howard T. Odum
4246:
4244:Radhika Nagpal
4241:
4236:
4231:
4226:
4221:
4216:
4214:Niklas Luhmann
4211:
4206:
4201:
4196:
4191:
4186:
4181:
4176:
4171:
4166:
4161:
4156:
4151:
4146:
4141:
4139:George Dantzig
4136:
4134:Manfred Clynes
4131:
4126:
4121:
4116:
4111:
4106:
4101:
4099:Margaret Boden
4096:
4091:
4086:
4081:
4076:
4071:
4066:
4061:
4059:Victor Aladjev
4056:
4050:
4048:
4042:
4041:
4038:
4037:
4035:
4034:
4024:
4019:
4014:
4009:
4004:
3999:
3994:
3989:
3984:
3978:
3975:
3974:
3972:
3971:
3966:
3961:
3956:
3951:
3949:Living systems
3946:
3941:
3936:
3934:Control theory
3930:
3924:
3918:
3917:
3915:
3914:
3909:
3904:
3899:
3894:
3888:
3886:
3882:
3881:
3879:
3878:
3873:
3868:
3863:
3858:
3853:
3848:
3843:
3838:
3833:
3828:
3822:
3820:
3812:
3811:
3804:
3803:
3796:
3789:
3781:
3775:
3774:
3760:
3759:External links
3757:
3755:
3754:
3747:
3727:
3717:
3697:
3690:
3668:
3655:
3640:
3627:
3605:
3598:
3569:
3528:
3517:(2): 181–205.
3501:
3467:"On Governors"
3457:
3450:
3430:
3407:
3370:
3343:(3): 119–128.
3327:
3267:
3230:(2): 237–273.
3210:
3161:
3110:
3090:
3083:. NASA. 2016.
3068:
3054:
3040:
3028:
3021:
2995:
2988:
2964:
2951:
2944:
2918:
2911:
2886:
2879:
2863:"Figure 16.2:
2854:978-0078028168
2853:
2828:
2818:
2796:
2789:
2769:
2762:
2740:
2733:
2707:
2700:
2678:
2671:
2651:
2640:
2633:
2611:
2604:
2582:
2575:
2549:
2523:
2505:(2): 351–353.
2479:
2476:on 2014-10-06.
2450:
2421:(3): 783–835.
2405:
2378:(3): 119–128.
2362:
2336:
2329:
2308:
2301:
2281:
2254:
2247:
2227:
2216:(1): 142–147.
2200:
2180:
2153:
2146:
2123:
2116:
2094:
2066:
2064:
2061:
2059:
2058:
2052:
2047:
2041:
2035:
2029:
2023:
2014:
2008:
2005:Control theory
2002:
1996:
1990:
1988:
1985:
1943:Norbert Wiener
1842:introduced by
1835:
1832:
1788:
1785:
1783:in 1988–1994.
1755:
1754:
1745:Norbert Wiener
1725:In economics,
1722:
1719:
1700:
1697:
1692:
1691:
1687:
1683:
1679:
1659:
1656:
1632:adrenal cortex
1593:erythropoiesis
1589:blood pressure
1562:
1559:
1539:fuel injection
1500:
1497:
1495:
1492:
1483:
1482:
1463:
1457:
1454:
1449:
1439:
1427:
1416:
1412:
1403:
1396:
1387:
1374:ratio β:
1350:equipment and
1328:Main article:
1325:
1322:
1299:
1298:
1287:
1278:
1275:
1272:
1269:
1264:
1261:
1255:
1249:
1246:
1243:
1240:
1236:
1231:
1227:
1221:
1218:
1213:
1210:
1207:
1203:
1199:
1196:
1193:
1190:
1187:
1184:
1181:
1143:
1142:
1131:
1122:
1119:
1116:
1113:
1109:
1104:
1098:
1095:
1092:
1089:
1084:
1081:
1075:
1072:
1023:
1022:
1011:
1003:
1000:
995:
989:
986:
983:
980:
976:
971:
966:
963:
897:
896:
893:
890:
887:
884:
881:
869:
868:
849:Main article:
846:
843:
842:
841:
824:
820:
809:
792:
788:
773:
772:
760:
756:
753:
750:
747:
741:
738:
734:
727:
723:
719:
715:
712:
706:
703:
700:
697:
691:
686:
682:
674:
670:
666:
661:
657:
654:
651:
648:
642:
636:
632:
628:
624:
621:
618:
615:
612:
594:PID controller
453:
450:
448:
445:
437:
436:
421:
394:
369:
330:
312:
297:
290:
283:
268:
260:
257:
228:refers to the
206:control theory
147:
144:
109:feedback loops
26:
9:
6:
4:
3:
2:
4468:
4457:
4454:
4452:
4449:
4447:
4444:
4442:
4439:
4437:
4434:
4433:
4431:
4416:
4415:
4406:
4404:
4403:
4398:
4394:
4392:
4391:
4382:
4381:
4378:
4372:
4369:
4367:
4364:
4363:
4361:
4359:Organizations
4357:
4351:
4348:
4346:
4343:
4341:
4338:
4337:
4335:
4331:
4325:
4322:
4320:
4317:
4315:
4312:
4310:
4309:Kevin Warwick
4307:
4305:
4302:
4300:
4297:
4295:
4292:
4290:
4287:
4285:
4282:
4280:
4277:
4275:
4272:
4270:
4267:
4265:
4262:
4260:
4257:
4255:
4252:
4250:
4247:
4245:
4242:
4240:
4237:
4235:
4232:
4230:
4227:
4225:
4224:Margaret Mead
4222:
4220:
4217:
4215:
4212:
4210:
4207:
4205:
4202:
4200:
4197:
4195:
4192:
4190:
4187:
4185:
4184:Lydia Kavraki
4182:
4180:
4177:
4175:
4172:
4170:
4169:Barbara Grosz
4167:
4165:
4162:
4160:
4157:
4155:
4152:
4150:
4147:
4145:
4142:
4140:
4137:
4135:
4132:
4130:
4127:
4125:
4122:
4120:
4117:
4115:
4112:
4110:
4107:
4105:
4102:
4100:
4097:
4095:
4092:
4090:
4087:
4085:
4082:
4080:
4077:
4075:
4072:
4070:
4069:Ruzena Bajcsy
4067:
4065:
4062:
4060:
4057:
4055:
4052:
4051:
4049:
4047:
4043:
4032:
4028:
4025:
4023:
4020:
4018:
4015:
4013:
4010:
4008:
4005:
4003:
4000:
3998:
3995:
3993:
3990:
3988:
3985:
3983:
3980:
3979:
3976:
3970:
3967:
3965:
3962:
3960:
3957:
3955:
3952:
3950:
3947:
3945:
3942:
3940:
3937:
3935:
3932:
3931:
3928:
3925:
3919:
3913:
3910:
3908:
3905:
3903:
3900:
3898:
3895:
3893:
3892:Doubling time
3890:
3889:
3887:
3883:
3877:
3874:
3872:
3869:
3867:
3864:
3862:
3859:
3857:
3854:
3852:
3849:
3847:
3844:
3842:
3839:
3837:
3834:
3832:
3829:
3827:
3824:
3823:
3821:
3817:
3813:
3809:
3802:
3797:
3795:
3790:
3788:
3783:
3782:
3779:
3771:
3767:
3763:
3762:
3750:
3748:9780521000994
3744:
3740:
3739:
3731:
3724:
3720:
3718:9781139458603
3714:
3710:
3709:
3701:
3693:
3687:
3682:
3681:
3672:
3665:
3659:
3652:
3651:
3644:
3637:
3631:
3623:
3616:
3609:
3601:
3599:9780863412806
3595:
3591:
3587:
3583:
3576:
3574:
3558:
3554:
3550:
3546:
3539:
3532:
3524:
3520:
3516:
3512:
3505:
3497:
3493:
3488:
3483:
3479:
3475:
3468:
3461:
3453:
3451:9780521566865
3447:
3443:
3442:
3434:
3417:
3411:
3403:
3399:
3394:
3389:
3386:(2): 99–128.
3385:
3381:
3374:
3366:
3362:
3358:
3354:
3350:
3346:
3342:
3338:
3331:
3323:
3319:
3315:
3311:
3307:
3303:
3299:
3295:
3291:
3287:
3283:
3279:
3271:
3263:
3259:
3255:
3251:
3246:
3241:
3237:
3233:
3229:
3225:
3221:
3214:
3206:
3202:
3197:
3192:
3188:
3184:
3181:(3): L03701.
3180:
3176:
3172:
3165:
3157:
3153:
3149:
3145:
3141:
3137:
3133:
3129:
3125:
3121:
3114:
3107:
3103:
3101:
3094:
3086:
3082:
3078:
3072:
3066:
3065:
3061:Herman Daly,
3058:
3052:
3051:
3044:
3037:
3032:
3024:
3022:9780691116242
3018:
3014:
3010:
3006:
2999:
2991:
2989:9781135623722
2985:
2981:
2977:
2976:
2968:
2961:
2955:
2947:
2945:9780750678445
2941:
2937:
2933:
2929:
2922:
2914:
2912:9781614993681
2908:
2904:
2900:
2893:
2891:
2882:
2880:9781420058888
2876:
2872:
2868:
2866:
2856:
2850:
2846:
2845:
2838:
2832:
2825:
2821:
2819:9781420037272
2815:
2811:
2807:
2800:
2792:
2790:9780495667728
2786:
2782:
2781:
2773:
2765:
2763:9788131759523
2759:
2755:
2751:
2744:
2736:
2734:9788120319523
2730:
2726:
2722:
2718:
2711:
2703:
2701:9780023749100
2697:
2693:
2689:
2682:
2674:
2672:9780521835398
2668:
2664:
2663:
2655:
2649:
2644:
2636:
2634:9788120319523
2630:
2626:
2622:
2615:
2607:
2605:9780080478753
2601:
2597:
2593:
2586:
2578:
2576:9788120319523
2572:
2568:
2564:
2560:
2553:
2545:
2541:
2537:
2530:
2528:
2516:
2512:
2508:
2504:
2500:
2493:
2486:
2484:
2472:
2468:
2461:
2454:
2446:
2442:
2437:
2432:
2428:
2424:
2420:
2416:
2409:
2401:
2397:
2393:
2389:
2385:
2381:
2377:
2373:
2366:
2351:
2347:
2340:
2332:
2330:9781118684733
2326:
2322:
2321:
2312:
2304:
2302:9788120336780
2298:
2294:
2293:
2285:
2278:
2273:
2268:
2267:
2258:
2250:
2248:9788120344051
2244:
2240:
2239:
2231:
2223:
2219:
2215:
2211:
2204:
2198:
2197:9780072389159
2194:
2190:
2184:
2176:
2172:
2168:
2164:
2157:
2149:
2147:9780801868955
2143:
2139:
2138:
2130:
2128:
2119:
2117:9780716728290
2113:
2109:
2105:
2098:
2090:
2083:
2076:
2074:
2072:
2067:
2056:
2055:Step response
2053:
2051:
2048:
2045:
2042:
2039:
2036:
2033:
2030:
2027:
2024:
2018:
2015:
2012:
2009:
2006:
2003:
2000:
1997:
1995:
1992:
1991:
1984:
1982:
1978:
1974:
1970:
1964:
1959:
1956:
1950:
1946:
1944:
1938:
1934:
1932:
1927:
1924:
1922:
1918:
1914:
1912:
1907:
1903:
1899:
1894:
1892:
1888:
1884:
1880:
1876:
1872:
1868:
1864:
1856:
1851:
1847:
1845:
1841:
1831:
1829:
1825:
1820:
1818:
1814:
1810:
1802:
1798:
1793:
1784:
1782:
1778:
1775:
1771:
1767:
1764:
1760:
1753:
1750:
1749:
1748:
1746:
1742:
1738:
1734:
1732:
1728:
1718:
1716:
1710:
1706:
1696:
1677:
1676:
1675:
1673:
1669:
1665:
1655:
1653:
1649:
1645:
1641:
1637:
1633:
1629:
1625:
1621:
1618:
1612:
1610:
1606:
1602:
1598:
1597:human anatomy
1594:
1590:
1586:
1577:
1572:
1568:
1558:
1556:
1552:
1551:refrigerators
1548:
1544:
1540:
1536:
1532:
1528:
1520:
1515:
1510:
1506:
1491:
1488:
1461:
1455:
1452:
1447:
1437:
1425:
1414:
1410:
1401:
1394:
1385:
1377:
1376:
1375:
1373:
1369:
1363:
1360:
1355:
1353:
1349:
1345:
1336:
1331:
1321:
1319:
1315:
1310:
1308:
1304:
1285:
1276:
1273:
1270:
1267:
1262:
1259:
1253:
1247:
1244:
1241:
1238:
1234:
1229:
1225:
1219:
1216:
1211:
1208:
1205:
1201:
1197:
1194:
1191:
1188:
1185:
1182:
1179:
1167:
1166:
1165:
1163:
1159:
1154:
1152:
1148:
1129:
1120:
1117:
1114:
1111:
1107:
1102:
1096:
1093:
1090:
1087:
1082:
1079:
1073:
1070:
1063:
1062:
1061:
1059:
1054:
1052:
1048:
1044:
1040:
1036:
1032:
1028:
1009:
1001:
998:
993:
987:
984:
981:
978:
974:
969:
964:
961:
952:
951:
950:
947:
945:
938: >0.
937:
932:
928:
926:
922:
919:proposed the
918:
914:
913:Harry Nyquist
910:
906:
905:step response
902:
894:
891:
888:
885:
882:
879:
878:
877:
876:
872:
866:
865:
864:
862:
858:
852:
840:
822:
818:
810:
808:
807:integral time
790:
786:
778:
777:
776:
758:
751:
745:
739:
736:
732:
725:
721:
717:
713:
710:
701:
695:
689:
684:
680:
672:
668:
664:
659:
652:
646:
640:
634:
630:
626:
602:
601:
600:
597:
595:
590:
588:
584:
580:
576:
572:
568:
564:
560:
556:
551:
549:
545:
541:
537:
533:
529:
525:
521:
517:
513:
509:
501:
497:
493:
489:
485:
480:
475:
471:
467:
458:
441:
434:
430:
426:
422:
419:
415:
411:
407:
403:
399:
395:
392:
388:
385:
381:
377:
374:
370:
367:
363:
359:
355:
351:
347:
343:
339:
335:
331:
328:
324:
320:
317:
313:
310:
306:
302:
298:
295:
291:
288:
284:
281:
277:
273:
269:
266:
263:
262:
256:
254:
250:
246:
241:
238:
235:In contrast,
233:
231:
227:
223:
219:
214:
211:
207:
202:
200:
196:
192:
188:
183:
181:
177:
174:; whereas in
173:
169:
165:
160:
152:
138:
134:
132:
128:
123:
121:
117:
112:
110:
106:
102:
98:
94:
90:
85:
83:
79:
75:
70:
67:
63:
59:
55:
48:
43:
37:
36:reinforcement
33:
19:
4412:
4400:
4388:
4333:Applications
4289:Katia Sycara
4189:James J. Kay
4179:Mike Jackson
4114:Murray Bowen
4012:Pharmacology
4007:Neuroscience
3906:
3769:
3737:
3730:
3722:
3707:
3700:
3679:
3671:
3663:
3658:
3648:
3643:
3630:
3621:
3608:
3589:
3585:
3560:. Retrieved
3548:
3544:
3531:
3514:
3510:
3504:
3477:
3473:
3460:
3440:
3433:
3422:. Retrieved
3410:
3383:
3379:
3373:
3340:
3336:
3330:
3281:
3277:
3270:
3227:
3223:
3213:
3178:
3174:
3164:
3123:
3119:
3113:
3098:
3097:Fig. TS.17,
3093:
3080:
3071:
3062:
3057:
3048:
3043:
3031:
3012:
3008:
2998:
2979:
2974:
2967:
2959:
2954:
2935:
2931:
2921:
2902:
2870:
2864:
2843:
2836:
2831:
2823:
2809:
2799:
2779:
2772:
2753:
2743:
2725:fundamentals
2724:
2720:
2710:
2691:
2681:
2661:
2654:
2643:
2624:
2614:
2595:
2585:
2566:
2562:
2552:
2535:
2515:the original
2502:
2498:
2471:the original
2466:
2453:
2418:
2414:
2408:
2375:
2371:
2365:
2354:. Retrieved
2349:
2339:
2319:
2311:
2291:
2284:
2275:
2265:
2257:
2237:
2230:
2213:
2209:
2203:
2188:
2183:
2166:
2162:
2156:
2136:
2107:
2097:
2088:
1980:
1976:
1972:
1969:degenerative
1968:
1966:
1961:
1952:
1948:
1940:
1936:
1928:
1925:
1915:
1910:
1895:
1887:steam engine
1860:
1837:
1821:
1806:
1768:and leading
1766:George Soros
1756:
1751:
1735:
1724:
1712:
1693:
1661:
1636:hypothalamus
1613:
1582:
1543:carburettors
1541:systems and
1524:
1486:
1484:
1364:
1356:
1341:
1311:
1306:
1300:
1176:Error signal
1161:
1157:
1155:
1150:
1146:
1144:
1057:
1055:
1042:
1038:
1034:
1030:
1026:
1024:
948:
941:
935:
925:Nyquist plot
898:
874:
873:
870:
854:
838:
806:
774:
598:
591:
586:
582:
574:
570:
566:
562:
558:
554:
552:
543:
539:
523:
515:
507:
505:
499:
495:
491:
487:
483:
482:A regulator
245:oscillations
242:
234:
225:
221:
215:
209:
203:
184:
161:
157:
124:
113:
86:
71:
57:
53:
52:
4441:Cybernetics
4279:Peter Senge
4274:John Seddon
4264:Qian Xuesen
4199:George Klir
4002:Engineering
3939:Cybernetics
3921:Theoretical
3871:Recommender
3861:Multi-agent
3856:Information
3551:(1): 1–18.
3480:: 270–283.
2169:(1): 4–13.
2011:Cybernetics
1999:Biofeedback
1931:cybernetics
1840:water clock
1828:water vapor
1809:cloud cover
1777:Herman Daly
1690:+ 92 kJ/mol
1646:to secrete
1624:physiologic
1571:Homeostasis
909:instability
563:temperature
532:'set point'
470:Homeostasis
433:homeostatic
429:blood sugar
406:demodulator
373:delta-sigma
354:integration
350:subtraction
191:mathematics
187:engineering
180:equilibrium
172:homeostasis
168:biochemical
131:cloud cover
105:equilibrium
97:oscillation
4430:Categories
4294:Eric Trist
4149:Fred Emery
4046:Scientists
4022:Psychology
4017:Philosophy
3846:Ecological
3831:Biological
3562:January 2,
3424:2013-05-03
2598:. Newnes.
2356:2014-06-08
2063:References
1896:The term "
1883:James Watt
1875:millstones
1865:had built
1781:World Bank
1585:baroreflex
1565:See also:
1503:See also:
571:electrical
548:regulation
528:subtracted
474:Allostasis
464:See also:
435:processes.
368:functions.
327:distortion
325:, reduces
319:amplifiers
3959:Systemics
3388:CiteSeerX
3365:0921-8181
3306:0036-8075
3254:0894-8755
3205:1944-8007
3148:1476-4687
2431:CiteSeerX
2400:0921-8181
1977:balancing
1879:windmills
1844:Ktesibios
1763:financier
1759:heterodox
1721:Economics
1709:Emergence
1658:Chemistry
1638:secretes
1617:endocrine
1456:β
1303:loop gain
1274:β
1260:β
1254:−
1245:β
1212:β
1209:−
1189:β
1186:−
1118:β
1094:β
1051:bandwidth
1002:β
994:≈
985:β
901:oscillate
714:τ
702:τ
681:∫
579:regulator
536:regulator
425:organisms
362:logarithm
199:setpoints
176:mechanics
47:loop gain
4456:Feedback
4390:Category
3992:Dynamics
3982:Analysis
3885:Concepts
3851:Economic
3496:51751195
3322:16985005
3314:15802595
3262:16122908
3106:Archived
3085:Archived
3081:nasa.gov
1987:See also
1898:feedback
1731:real GDP
1652:cortisol
1620:hormones
1609:diabetes
1555:freezers
1527:ballcock
1519:ballcock
923:and the
402:waveform
346:addition
344:such as
259:Examples
255:fitted.
226:negative
222:negative
210:negative
87:Whereas
78:meltdown
66:fed back
62:function
4414:Commons
3997:Ecology
3987:Biology
3866:Nervous
3836:Complex
3345:Bibcode
3286:Bibcode
3278:Science
3232:Bibcode
3183:Bibcode
3156:4321239
3128:Bibcode
2960:Biology
2423:Bibcode
2380:Bibcode
2108:Ecology
1911:reduced
1834:History
1634:. The
1601:glucose
1561:Biology
1160:–β
837:is the
805:is the
384:quality
366:antilog
270:In the
253:dampers
230:valence
164:biology
4402:Portal
4027:Theory
3923:fields
3876:Social
3816:System
3745:
3715:
3688:
3596:
3494:
3448:
3390:
3363:
3320:
3312:
3304:
3260:
3252:
3203:
3154:
3146:
3120:Nature
3019:
2986:
2942:
2909:
2877:
2851:
2816:
2787:
2760:
2731:
2698:
2669:
2631:
2602:
2573:
2433:
2398:
2327:
2299:
2245:
2222:255468
2220:
2195:
2144:
2114:
1889:, and
1817:albedo
1686:⇌ 2 NH
1359:op-amp
1305:β
1283:
1127:
1007:
775:where
522:, say
472:, and
408:in an
364:, and
309:sensor
303:, the
280:demand
276:supply
220:, use
195:stable
3819:types
3618:(PDF)
3541:(PDF)
3492:S2CID
3470:(PDF)
3419:(PDF)
3318:S2CID
3258:S2CID
3152:S2CID
3038:p.158
2518:(PDF)
2495:(PDF)
2474:(PDF)
2463:(PDF)
2218:JSTOR
2085:(PDF)
1979:, or
1955:Ashby
1795:Some
1682:+ 3 H
1553:, or
1348:audio
538:(say
526:) is
396:In a
387:audio
316:audio
305:speed
292:In a
4366:List
3743:ISBN
3713:ISBN
3686:ISBN
3594:ISBN
3564:2013
3446:ISBN
3361:ISSN
3310:PMID
3302:ISSN
3250:ISSN
3201:ISSN
3144:ISSN
3017:ISBN
2984:ISBN
2940:ISBN
2907:ISBN
2875:ISBN
2849:ISBN
2814:ISBN
2785:ISBN
2758:ISBN
2729:ISBN
2696:ISBN
2667:ISBN
2629:ISBN
2600:ISBN
2571:ISBN
2396:ISSN
2325:ISBN
2297:ISBN
2243:ISBN
2193:ISBN
2142:ISBN
2112:ISBN
1853:The
1772:and
1707:and
1569:and
1517:The
1507:and
1366:and
1049:and
587:heat
555:heat
378:and
278:and
56:(or
34:and
3826:Art
3553:doi
3519:doi
3482:doi
3398:doi
3353:doi
3294:doi
3282:308
3240:doi
3191:doi
3136:doi
3124:326
2859:or
2839:in
2540:doi
2507:doi
2441:doi
2388:doi
2171:doi
1877:in
1587:in
1390:out
915:of
859:at
583:gas
423:In
371:In
332:In
314:In
299:In
285:In
251:or
204:In
185:In
162:In
99:or
4432::
3768:.
3721:.
3620:.
3592:.
3590:ff
3584:.
3572:^
3549:13
3547:.
3543:.
3513:.
3490:.
3478:16
3476:.
3472:.
3396:.
3384:66
3382:.
3359:.
3351:.
3341:64
3316:.
3308:.
3300:.
3292:.
3280:.
3256:.
3248:.
3238:.
3228:18
3226:.
3222:.
3199:.
3189:.
3179:33
3177:.
3173:.
3150:.
3142:.
3134:.
3122:.
3079:.
3015:.
3013:ff
3007:.
2982:.
2980:ff
2938:.
2936:ff
2930:.
2901:.
2889:^
2822:.
2808:.
2752:.
2723:IT
2719:.
2690:.
2623:.
2594:.
2569:.
2567:ff
2561:.
2526:^
2503:99
2501:.
2497:.
2482:^
2465:.
2439:.
2429:.
2419:77
2417:.
2394:.
2386:.
2376:64
2348:.
2274:.
2214:20
2212:.
2167:28
2165:.
2126:^
2106:.
2087:.
2070:^
1975:,
1971:,
1881:.
1733:.
1611:.
1557:.
1549:,
1537:,
1466:in
1442:in
1354:.
1320:.
1035:A
1027:A
946:.
911:.
510:)
468:,
410:FM
360:,
356:,
352:,
348:,
208:,
201:.
189:,
182:.
129:,
122:.
95:,
84:.
4033:)
4029:(
3800:e
3793:t
3786:v
3751:.
3694:.
3602:.
3566:.
3555::
3525:.
3521::
3515:3
3484::
3454:.
3427:.
3404:.
3400::
3367:.
3355::
3347::
3324:.
3296::
3288::
3264:.
3242::
3234::
3207:.
3193::
3185::
3158:.
3138::
3130::
3102:,
3025:.
2992:.
2948:.
2915:.
2883:.
2867:"
2857:.
2793:.
2766:.
2737:.
2704:.
2675:.
2637:.
2608:.
2579:.
2546:.
2542::
2509::
2447:.
2443::
2425::
2402:.
2390::
2382::
2359:.
2333:.
2305:.
2272:1
2251:.
2224:.
2177:.
2173::
2150:.
2120:.
1688:3
1684:2
1680:2
1678:N
1487:A
1481:.
1462:V
1453:1
1448:=
1438:V
1430:1
1426:R
1419:2
1415:R
1411:+
1406:1
1402:R
1395:=
1386:V
1307:A
1286:.
1277:A
1271:+
1268:1
1263:D
1248:A
1242:+
1239:1
1235:I
1230:=
1226:)
1220:I
1217:O
1206:1
1202:(
1198:I
1195:=
1192:O
1183:I
1180:=
1162:O
1158:I
1151:D
1147:A
1130:,
1121:A
1115:+
1112:1
1108:D
1103:+
1097:A
1091:+
1088:1
1083:I
1080:A
1074:=
1071:O
1058:D
1043:A
1039:A
1031:A
1010:,
999:1
988:A
982:+
979:1
975:A
970:=
965:I
962:O
936:A
823:d
819:T
791:i
787:T
759:)
755:)
752:t
749:(
746:e
740:t
737:d
733:d
726:d
722:T
718:+
711:d
705:)
699:(
696:e
690:t
685:0
673:i
669:T
665:1
660:+
656:)
653:t
650:(
647:e
641:(
635:p
631:K
627:=
623:)
620:t
617:(
614:V
611:M
575:S
567:E
559:T
544:T
540:R
524:E
516:D
508:T
502:.
500:D
496:S
492:E
488:T
484:R
420:.
282:.
38:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
