A positive feedback loop is a specific type of feedback loop in which the effects of a perturbation on a system result in an increase in the magnitude of the perturbation. It is also known as exacerbating feedback or self-reinforcing feedback. Positive feedback loops are distinct from negative feedback loops, where the effects of a perturbation on a system lead to a decrease in the magnitude of the perturbation.
Key Facts
- Definition: A positive feedback loop is a type of feedback loop in which the effects of a perturbation on a system include an increase in the magnitude of the perturbation. It is also known as exacerbating feedback or self-reinforcing feedback.
- Characteristics: Positive feedback loops tend to cause system instability. When the loop gain is positive and above 1, there can be exponential growth, increasing oscillations, chaotic behavior, or other divergences from equilibrium. System parameters may accelerate towards extreme values, potentially damaging or destroying the system.
- Examples: Positive feedback loops can be found in various fields. In biology, platelet clotting is an example of a positive feedback loop, where the release of chemicals from a damaged blood vessel wall initiates the formation of a blood clot, which in turn releases more chemicals, speeding up the process until the clotting is complete. Positive feedback can also be observed in economic systems, where it can cause boom-then-bust cycles.
Characteristics of Positive Feedback Loops
Positive feedback loops tend to cause system instability. When the loop gain is positive and above 1, there can be exponential growth, increasing oscillations, chaotic behavior, or other divergences from equilibrium. System parameters may accelerate towards extreme values, potentially damaging or destroying the system.
Examples of Positive Feedback Loops
Positive feedback loops can be found in various fields. In biology, platelet clotting is an example of a positive feedback loop. When a blood vessel wall is damaged, chemicals are released that initiate the formation of a blood clot. As the blood clot forms, it releases more chemicals, which in turn speed up the process until the clotting is complete.
Positive feedback can also be observed in economic systems. For example, a boom in the stock market can lead to increased investment, which can further increase the value of stocks. This can create a bubble, which can eventually burst, leading to a sharp decline in stock prices.
Conclusion
Positive feedback loops are a type of feedback loop that can cause system instability. They are characterized by an increase in the magnitude of a perturbation and can be found in various fields, including biology and economics.
Sources
- Positive feedback – Wikipedia
- Positive and Negative Feedback Loops in Biology – Albert.io
- The Definition of Negative and Positive Feedback Loops in 200 Words or Less – HubSpot Blog
FAQs
What is a positive feedback loop?
A positive feedback loop is a type of feedback loop in which the effects of a perturbation on a system result in an increase in the magnitude of the perturbation.
What are some characteristics of positive feedback loops?
Positive feedback loops tend to cause system instability. When the loop gain is positive and above 1, there can be exponential growth, increasing oscillations, chaotic behavior, or other divergences from equilibrium.
What are some examples of positive feedback loops?
Examples of positive feedback loops include platelet clotting in biology and boom-then-bust cycles in economics.
How do positive feedback loops differ from negative feedback loops?
Positive feedback loops cause an increase in the magnitude of a perturbation, while negative feedback loops cause a decrease in the magnitude of a perturbation.
What are some real-world examples of positive feedback loops?
Real-world examples of positive feedback loops include the runaway greenhouse effect, population explosions, and the stock market bubble.
What are some ways to control positive feedback loops?
Positive feedback loops can be controlled by introducing negative feedback loops or by limiting the gain of the positive feedback loop.
What are some of the benefits of positive feedback loops?
Positive feedback loops can be beneficial in some cases. For example, they can be used to amplify signals or to create oscillations.
What are some of the drawbacks of positive feedback loops?
Positive feedback loops can also be detrimental. For example, they can lead to instability, chaos, and even the destruction of a system.