Feedback facts for kids

Feedback is like a special loop where the result of something affects what happens next. It's a connection between a cause and its effect in a process.

Electronic Feedback Loops

In electronics, feedback happens when the result, or "output," of a system changes what goes into it next, which is called the "input." This creates a "feedback loop."

Sometimes, the output makes the input stronger. This is called positive feedback. It can make things grow quickly. Other times, the output reduces or stops the input. This is called negative feedback.

What is Positive Feedback?

Imagine a sound system with a microphone and a speaker. If the sound from the speaker goes back into the microphone, it creates a loop. The sound and electrical energy travel faster and faster around this loop. This is why you hear a low hum that quickly turns into a loud squeal.

This is an example of positive feedback. The sound coming out of the speaker makes the sound going into the microphone stronger. It reinforces the input.

What is Negative Feedback?

Think about two mirrors facing each other. They reflect each other over and over again. But with each reflection, the image gets a little bit smaller. The images keep getting smaller until you can't see them anymore.

This is an example of negative feedback. The reflection, which is the output, makes the next image, or input, smaller. It reduces the input.

Global Warming and Feedback

A real-world example of positive feedback can be seen with melting glaciers. When warm temperatures cause a glacier to melt, areas once covered by ice become water or land. Ice and snow reflect heat from the sun, but water and land absorb heat.

So, as more ice melts, more dark water and land appear. These dark areas absorb more heat, which makes the glacier melt even faster. This type of positive feedback, where heat causes more heat absorption, is sometimes called "thermal runaway."

Cybernetics: The Study of Feedback

An American mathematician named Norbert Wiener helped make feedback loops well known. He wrote a book called Cybernetics in 1948.

Cybernetics is the study of these feedback loops. It looks at how they work in communication and how they help control different systems.

Images for kids

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  Maintaining a desired system performance despite disturbance using negative feedback to reduce system error

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  An example of a negative feedback loop with goals

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  A positive feedback loop example

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  Feedback can give rise to incredibly complex behaviors. The Mandelbrot set (black) within a continuously colored environment is plotted by repeatedly feeding back values through a simple equation and recording the points on the imaginary plane that fail to diverge

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  A 4-bit ring counter using D-type flip flops

See also

In Spanish: Realimentación para niños