Feedback - Wikiparency

# Feedback Feedback routes a system's outputs back as inputs, creating circular causality that enables self-regulation. [[Negative_feedback|Negative feedback]] opposes change and stabilizes; [[Positive_feedback|positive feedback]] amplifies change and can produce growth, oscillation, or runaway. Loop gain, phase, delays, and bipolar combinations appear in electronics, [[Biology|biology]], climate, cognition, and cybernetic machines.  ## Microsims (promoted from legacy — three.js first) ### MicroSim spec - **Recommended sim type:** feedback loop - **Microsimmability score:** 90/100 - **Layout:** drawing region (canvas) on top; control region (sliders/buttons) below. ### Parameters (tunable controls) - `Loop gain` - `Delay` - `Disturbance` ### What animates An output [[Signal|signal]] loops back and you watch the system settle, oscillate, or blow up as gain and delay change. ### Learning objective Predict how loop gain and delay determine whether feedback stabilizes or destabilizes a system. ### MicroSim spec - **Recommended sim type:** feedback loop - **Microsimmability score:** 90/100 - **Layout:** drawing region (canvas) on top; control region (sliders/buttons) below. ### Parameters (tunable controls) - `Gain` - `Delay` - `Setpoint` ### What animates A [[Signal|signal]] circulates the loop and grows, settles, or oscillates as gain and delay change. ### Learning objective Show how loop gain and delay determine whether a feedback system stabilizes or runs away.   ## Microsims — three.js ### Feedback (three.js) <div class="microsim-player"> <iframe src="https://wikitube-3d-microsims.netlify.app/Feedback.html" width="100%" height="620" frameborder="0" loading="lazy" sandbox="allow-scripts allow-same-origin" title="Feedback — three.js microsim"></iframe> </div> **Open it full-screen:** [Feedback.html](https://wikitube-3d-microsims.netlify.app/Feedback.html) · library `threejs` · route `microsim/threejs/` ## Microsims — p5.js ### Feedback (p5.js) · `y → input` <div class="microsim-player"> <iframe src="https://editor.p5js.org/sciencenibber/full/sgQFSGMnw" width="100%" height="480" frameborder="0" loading="lazy" sandbox="allow-scripts allow-same-origin" title="Feedback — p5.js microsim"></iframe> </div> *Routing a system's output back to its input — the single idea that makes regulation, oscillation, and instability possible.* **Open in the editor:** [▶ fork this sketch](https://editor.p5js.org/sciencenibber/sketches/sgQFSGMnw) · movement *VI · Control theory & estimation* · library `p5js` ### Related microsims Live sims on neighbouring articles — 6 of them inside this article's own Wikipedia link tree: - [[Agent-based_model]] *(in tree)* - [[Complex_system]] *(in tree)* - [[Emergence]] *(in tree)* - [[Network_theory]] *(in tree)* - [[Phase_space]] *(in tree)* - [[Self-organization]] *(in tree)* *Sim hosted off-article; the article owns the reference, not the runtime (WIKI_RULES §10.4). Placed by `g08_place_microsims.py`.*   ## Images <figure class="wt-gifplate"> <img src="https://commons.wikimedia.org/wiki/Special:FilePath/Central_nervous_system.gif" alt="Biological Feedback" loading="lazy" decoding="async"> <figcaption><strong>Biological Feedback</strong> — Demonstrate feedback loops in nervous system control.<br> <span class="wt-credit">Wikimedia Commons · <strong>licence pending verification</strong> (run <code>g17_gif_verify.py</code> on a networked lane) · <a href="https://commons.wikimedia.org/wiki/File:Central_nervous_system.gif">Details</a></span></figcaption> </figure> *Still companion to the 1 live microsim above: the sim is the instrument, the plate is the glance. §15 keeps the player first; this sits in the image slot on [[Feedback]].*  ## Reveal %%REVEAL:p5%% %%REVEAL:mermaid%% --- *Concept aligned with [Wikipedia](https://en.wikipedia.org/wiki/Feedback); adapted text, where present, is licensed [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/).* ## Overview The loop is the atom of [[Cybernetics|cybernetics]] and [[Control_theory|control theory]]: [[Homeostasis|homeostasis]] in organisms and the [[Ecosystem|ecosystem]], regulator design in engineering, and self-steering in the [[Artificial_intelligence|artificial-intelligence]] stack all reduce to closed circuits of cause. Mapped qualitatively, loops become the [[Causal_loop_diagram|causal loop diagram]]; quantified, they become [[System_dynamics|system dynamics]] models over [[Stock_and_flow|stocks and flows]] evolving as a [[Dynamical_system|dynamical system]] with [[Attractor|attractors]] and [[Phase_transition|phase transitions]]. Interacting loops generate the signatures of the [[Complex_system|complex system]]—[[Emergence|emergence]], [[Self-organization|self-organization]], [[Chaos_theory|chaos]]—and drive adaptive processes from the [[Genetic_algorithm|genetic algorithm]] to [[Population_dynamics|population dynamics]], strategic play in [[Game_theory|game theory]], and signal regeneration studied in [[Information_theory|information theory]].  *Built to the [[WT!P5_js_Microsim_Master_Class|p5.js Master Class]].*  ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Feedback) : [Wikitube](https://en.wikitube.io/wiki/Feedback) ## Previous hub tags Hubs: `Systems`. Portals: [[PORTAL_Systems]], [[PORTAL_Feedback]].