# Positive feedback
## MicroSim spec
### Parameters (tunable controls)
- `Feedback gain` · 0–3 · fraction of output re-injected to reinforce it
- `Initial seed` · 0–10 · starting perturbation that gets amplified
- `Saturation cap` · 10–200 · ceiling where runaway growth flattens
### What animates
A value grows ever faster along an exponential trace until it hits the saturation ceiling.
### Learning objective
Show how positive feedback amplifies a perturbation into runaway growth until saturation.
## Links (Wikipedia order)
<!-- injected from _registry/childlinks/Positive_feedback.json (2026-07-30T02:09:12Z) -->
`Action_potential` · `Adaptive_control` · `Albedo` · [[Alexander_Bogdanov]] · `Alfred_J._Lotka` · [[Allenna_Leonard]] · [[Alternating_current]] · `Amplifier` · `Amplitude` · `Analogue_electronics` · [[Anatol_Rapoport]] · `Andrey_Korotayev` · `Annual_Review_of_Microbiology` · [[Anthony_Wilden]] · `Apoptosis` · `Armstrong_oscillator` · `Audio_engineer` · `Audio_feedback` · `Autocatalysis` · `Automation_and_Remote_Control` · `Bandwidth_(signal_processing)` · `Bank_run` · [[Barbara_J._Grosz]] · `Barkhausen_stability_criterion` · `Bernard_Crespi` · `Bimetallic_strip` · `Biodiversity` · [[Biological_system]] · `Bistability` · `Bit` · [[Block_diagram]] · `Bode_plot` · `Brian_May` · `Business_cycle` · [[Béla_H._Bánáthy]] · [[C._West_Churchman]] · `Cancer` · [[Carrying_capacity]] · `Caspase` · [[Causal_loop_diagram]] · `Causal_system` · `Cell_signaling` · `Cerebellum` · `Chain_letter` · `Chain_reaction` · [[Chaos_theory]] · [[Charles_A._S._Hall]] · `Chemical_reaction` · `Child_prodigy` · `Childbirth` · `Circular_cumulative_causation` · [[Claude_Shannon]] · `Closed-loop_controller` · `Closed-loop_transfer_function` · `Coefficient_diagram_method` · `Colpitts_oscillator` · [[Complex_system]] · `Computer_memory` · `Control_reconfiguration` · [[Control_theory]] · `Controllability` · [[Coupled_human–environment_system]] · `Crystal` · `Current_Biology` · [[Cybernetics]] · `Cytokine` · `Cytokine_storm` · `Deforestation` · `Demography` · `Dew_point` · `Digital_control` · `Digital_electronics` · [[Digital_signal_processing]] · `Distortion_(music)` · `Distributed_control_system` · `Distributed_parameter_system` · `Doctor_Who` · [[Donella_Meadows]] · [[Doubling_time]] · `Drought` · [[Earth_system_science]] · `Economic_system` · [[Ecosystem]] · [[Edsger_W._Dijkstra]] · [[Edward_Norton_Lorenz]] · `Electric_guitar` · [[Electric_motor]] · `Electronic_oscillator` · `Embedded_system` · `Energy-shaping_control` · [[Eric_Trist]] · `Estrogen` · `Evapotranspiration` · [[Evolution]] · `Evolutionary_arms_race` · `Exothermic_reaction` · `Explosion` · `Exponential_growth` · `Facebook` · `Ferguson_reflex` · `Filter_(signal_processing)` · [[Flip-flop_(electronics)]] · `Follicular_phase` · `Fossil` · `Fourier_transform` · `Fractional-order_control` · [[Francisco_Varela]] · `Fred_Emery_(psychologist)` · `Frequency` · [[Frequency_response]] · [[Fuzzy_control_system]] · `Fuzzy_logic` · `Gain_(electronics)` · [[George_Dantzig]] · [[George_Klir]] · `George_Modelski` · `George_Soros` · `Greenhouse_effect` · `Greenhouse_gas` · [[Gregory_Bateson]] · `Guitar_amplifier` · `Guitar_solo` · `Gunnar_Myrdal` · `H-infinity_loop-shaping` · `Hankel_singular_value` · `Harmonic_oscillator` · `Harold_Stephen_Black` · `Hartley_oscillator` · [[Heinz_von_Foerster]] · `High-frequency_trading` · `Hodgkin_cycle` · [[Howard_T._Odum]] · [[Humberto_Maturana]] · `Hybrid_computer` · `Hyman_Minsky` · `Hyperbolic_growth` · `Hyperlink` · `Hypothalamus` · `Hysteresis` · `I_Feel_Fine` · [[Ilya_Prigogine]] · `Industrial_control_system` · [[Information_system]] · `Input_impedance` · `Intelligent_control` · `Intergovernmental_Panel_on_Climate_Change` · [[James_Grier_Miller]] · [[James_J._Kay]] · [[Jay_Wright_Forrester]] · [[Jennifer_Wilby]] · `Jimi_Hendrix` · [[John_Seddon]] · `Journal_of_Mind_and_Behavior` · [[Kalman_filter]] · [[Kathleen_Carley]] · [[Katia_Sycara]] · `Kenneth_E._Boulding` · [[Kevin_Warwick]] · `Krener's_theorem` · `Lac_operon` · `Lactation` · `Language` · [[Laplace_transform]] · `Lead–lag_compensator` · `Least_squares` · [[Limiting_factor]] · [[List_of_systems_sciences_organizations]] · `List_of_systems_scientists` · [[Living_systems]] · `Locking_pliers` · [[Logic_gate]] · `Logistic_function` · [[Loudspeaker]] · `Low-pass_filter` · [[Ludwig_von_Bertalanffy]] · [[Lyapunov_stability]] · [[Lydia_Kavraki]] · `MIT_Press` · `Macrosociology` · [[Manfred_Clynes]] · [[Manuela_M._Veloso]] · [[Margaret_Boden]] · [[Margaret_Mead]] · [[Mary_Cartwright]] · `Matthew_effect` · `Meander` · [[Mechatronics]] · `Methane` · `Michael_Osterholm` · `Microphone` · [[Mihajlo_D._Mesarovic]] · `Mike_Jackson_(systems_scientist)` · `Miniature_snap-action_switch` · `Minor_loop_feedback` · `Minsky_moment` · [[Model_predictive_control]] · [[Molecular_dynamics]] · `Motion_control` · [[Multi-agent_system]] · `Multivibrator` · [[Murray_Bowen]] · `NOR_gate` · `Nationalisation_of_Northern_Rock` · `Nature_(journal)` · [[Negative_feedback]] · [[Nervous_system]] · `Network_effect` · [[Niklas_Luhmann]] · `Nitrous_oxide` · `Nonlinear_control` · [[Norbert_Wiener]] · [[Observability]] · `Ohio_State_University` · `Operant_conditioning` · [[Optimal_control]] · [[Oscillation]] · `Oscilloscope` · `Output_impedance` · `Ovulation` · `Oxytocin` · [[PID_controller]] · `Parasitic_oscillation` · `Parkinson's_disease` · `Peat` · [[Perceptual_control_theory]] · `Performance` · `Performance_appraisal` · [[Peter_Senge]] · `Phanerozoic` · `Phase_(waves)` · `Physiology` · `Platelet` · `Political_polarization` · `Ponzi_scheme` · `Population_biology` · [[Principia_Cybernetica]] · `Programmable_logic_controller` · `Prolactin` · `Public_address_system` · [[Qian_Xuesen]] · [[Quantization_(signal_processing)]] · `Quartz` · [[Radhika_Nagpal]] · `Reaction_rate` · [[Real-time_computing]] · [[Recommender_system]] · `Reflexivity_(social_theory)` · `Regenerative_circuit` · `Reinforcement` · `Richard_D._Alexander` · [[Robotics]] · `Robust_control` · `Rock_music` · `Root_locus_analysis` · `Routledge` · `Runaway_greenhouse_effect` · `Russell_L._Ackoff` · `Ruzena_Bajcsy` · `SCADA` · `Schmitt_trigger` · `Self-fulfilling_prophecy` · `Self-segregation` · `Servomechanism` · [[Signal-flow_graph]] · `Social_system` · [[Sociotechnical_system]] · `Sound_recording_and_reproduction` · `Sound_reinforcement_system` · `Stability_criterion` · `Stability_theory` · [[Stafford_Beer]] · `Stampede` · `State-space_representation` · `State_observer` · `Steady_state` · `Stefan–Boltzmann_law` · [[Stephanie_Forrest]] · `Stochastic_control` · `Strategic_complements` · `Superregenerative_receiver` · [[System]] · [[System_dynamics]] · [[System_identification]] · `Systemic_risk` · `Systemics` · `Systems_analysis` · `Systems_art` · [[Systems_biology]] · [[Systems_ecology]] · [[Systems_engineering]] · [[Systems_neuroscience]] · [[Systems_pharmacology]] · `Systems_philosophy` · `Systems_psychology` · [[Systems_science]] · [[Systems_theory]] · `Systems_theory_in_anthropology` · [[Systems_theory_in_archaeology]] · [[Systems_theory_in_political_science]] · [[Systems_thinking]] · `Søren_Absalon_Larsen` · `Tacoma_Narrows_Bridge_(1940)` · [[Talcott_Parsons]] · `Technological_singularity` · `Tessaleno_Devezas` · `The_Blind_Watchmaker` · `Thermal_runaway` · [[Transfer_function]] · [[Transistor]] · `Transpiration` · [[Twelve_leverage_points]] · [[Urban_metabolism]] · `Uterus` · `Vacuum_tube` · `Vicious_circle` · `Victor_Aladjev` · `Video` · `Video_camera` · `Video_feedback` · `Viral_video` · `W._Brian_Arthur` · [[Wayback_Machine]] · `Wien_bridge_oscillator` · `Wildfire` · `Working_memory` · `World-systems_theory` · `World_War_II` · [[Z-transform]]
## From the Real GENERATIVE library
*Positive feedback — placed from the Real G.E.N.E.R.A.T.I.V.E. course library (Engineering room). Source: Wikimedia Commons (via Wikipedia article media). [Details & license](https://commons.wikimedia.org/wiki/File:Stampede_loop.png).*
*Animated: Positive feedback — placed from the Real G.E.N.E.R.A.T.I.V.E. course library (Engineering room). Source: Wikimedia Commons (via Wikipedia article media). [Details & license](https://commons.wikimedia.org/wiki/File:R-S_mk2.gif).*
> Positive feedback (exacerbating feedback, self-reinforcing feedback) is a process that occurs in a feedback loop which exacerbates the effects of a small disturbance. That is, the effects of a perturbation on a system include an increase in the magnitude of the perturbation.[1] That is, A produces more of B which in turn produces more of A.[2] In contrast, a ([Wikipedia](https://en.wikipedia.org/wiki/Positive_feedback))
<!-- REAL-GENERATIVE-MEDIA:END -->
## Media (PD/CC)
<!-- MEDIA-DEPLOY:Positive_feedback/R-S_mk2.gif -->
!Gif Library/Logic gate/R-S mk2.gif
*R-S_mk2.gif · Napalm Llama · CC BY 2.0 · [source](https://commons.wikimedia.org/wiki/File:R-S_mk2.gif)*
<!-- /MEDIA-DEPLOY -->
> p5.js MicroSim stub · part of Systems Engineering · [Wikipedia source](https://en.wikipedia.org/wiki/Positive_feedback)
## Concept summary
Positive feedback (exacerbating [[Feedback|feedback]], self-reinforcing feedback) is a process that occurs in a feedback loop where the outcome of a process reinforces the inciting process to build momentum. As such, these forces can exacerbate the effects of a small disturbance.
## Build checklist
- [ ] Claim it: set `status: in-progress` + `lease` + `leased_at`
- [ ] Write the child page explaining the concept (tie it back to Systems Engineering)
- [ ] Finalize parameter ranges and defaults
- [ ] Implement the p5.js sketch (drawing + control regions)
- [ ] Add caption + the learning objective on the page
- [ ] Set `status: done`
## p5.js sketch
```javascript
// MicroSim: Positive feedback
const ARTICLE = "Positive_feedback";
let p1, p2, p3;
function setup() {
createCanvas(720, 520);
pixelDensity(2);
// feedback-loop sim — create the three sliders described above:
// Feedback gain (0–3), Initial seed (0–10), Saturation cap (10–200).
// TODO: build labelled sliders in the control region (below the drawing region).
}
function draw() {
background(248);
// TODO: read p1/p2/p3; render the feedback-loop in the drawing region and respond live.
// TODO: HUD — title + en.wikitube.io/wiki/Positive_feedback + control hints + live readouts.
}
```
---
Back to Systems Engineering
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## Semiotic profile
> *The semiotic universals this article invokes, machine-derived from the crossref — **unverified** (born so). Populated 2026-07-06 for the Systems room.*
**Universals (8):** 🟢 feedback (66) · 🟡 system (20) · 🟢 saturation (6) · 🟡 science (5) · 🟢 momentum (4) · 🟢 signal (2) · 🟢 force (2) · 🟢 oscillation (1)
**Enter by sign:** Systems Semiotic Gateway · Alphabetum · Icon Registry · ← Systems Portal
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## Wikipedia : Wikitube
**Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Positive_feedback) : [Wikitube](https://en.wikitube.io/wiki/Positive_feedback)
## Previous hub tags
Tree parents: [[Causal_loop_diagram]] · [[Control_theory]] · [[Cybernetics]] · [[Feedback]] · [[Operations_research]] · [[Reliability_engineering]] · [[Self-organization]] · [[System_dynamics]] · [[Systems_engineering]] · [[Systems_science]] · [[Systems_theory]].
Legacy hubs: none.
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*Sources: 4 legacy notes. Minted wave 1, 2026-07-30 (v1.6 order).*