Sound To Electricity: How Do Microphones And Speakers Work?


Imagine turning turning sound into usable electricity! Wouldn’t that be amazing? Well, it already happens everyday, watch this video to find out how!

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Youtube, it’s Cram. Sound. It is amazing, allowed us to perceive the world through vibrations in their air. And electricity, flowing electrons that power our modern world. These two seem like they couldn’t be more different, but in fact they are different forms of the same thing. They are both forms of energy, and can be converted to one another. How? To figure this out, lets use the microphone as a starting point. It takes sound in from the top part, which has several holes in it, processes it somehow, and then sends it off as electricity through a wire.It seems simple enough, except for the processing part.

Microphones are a kind of transducer, something that can convert one form of energy to another. In this case, it is sound to electricity. There are many kinds of microphones, but one thing they all have in common is called the diaphragm, a thin piece made of a material, commonly plastic, aluminum or paper. This acts in a similar fashion to our eardrums, it vibrates because of sound waves.

Ok, but our eardrums don’t convert sound into electricity. We’re all familiar with a simple electrical generator, right? Basically, there is a coil, typically a conductor like copper, and inside the coil is a magnet. As the magnet rotates/ moves, an electrical current passes through the coil. This is because of electromagnetism, and electricity can be used to make a magnet, the opposite is also true.

So when this material vibrates, it is attached to the magnet, therefore moving the magnet, thus creating an electrical signal. This signal is passed through a wire to a speaker, or anything that plays music. This speaker is also a transducer. It does the opposite though. Remember how electricity can be used to create a magnet? Well, that’s what’s happening. The electricity flows through the coiled conductor inside the speaker, in turn moving the magnet. This magnet usually moves a cone, instead of a thin material, which produces the sound. This is why larger speakers typically have more bass, since the cone is bigger, larger wavelengths can travel further, thus having more “oomph” and cleaner sound.

Wait, so if sound can make energy, why don’t we use it as a renewable source of energy? That’s because the amount of energy is extremely low, too low to even bother with. Or it would be the end of the energy crisis we face today. I hope you enjoyed this video as much as I appreciated you watching. Subscribe to stay up to date on all my latest science videos, and until next time, Cram Out.

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♫ ‘Daggers’ by Metiri
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