Tuesday, July 23, 2013

Feedback Loops

Until now, I've been talking about sustainable cycles. Cycles can be unsustainable, too. This usually happens due to a positive or negative feedback loop. In short, a feedback loop is where the amount at the end of the process is not the same than the amount at the beginning, so when the process is repeated, the results continue to be different.

Positive feedback loops end up with more than what they started with. The best example is putting a microphone in front of its own amplifier. Whatever goes into the microphone is made louder through the amplifier, which then feeds into the microphone, and gets amplified even louder than before. This cycle can repeat over and over again, getting louder and higher in pitch, until eventually, the speakers explode. There is a maximum capacity the system can handle, beyond which it catastrophically fails.

Negative feedback loops are the opposite, giving you continually less each time. A gross example of this would be survival experts who say to drink your own urine in emergency situations to recover lost water. While this is viable, your body does use the water it takes in for metabolic processes, so there is less water in your urine each time you release it. The end result of all negative feedback loops is that you run out of your power source and the process stops. Though this sounds less interesting than the catastrophic failure of an amplifier blowing out, what makes it interesting is seeing how people react to it, and to see what other forces take over while the negative feedback loop is weakening.

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