WEBVTT

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so what's a voice coil is that one of those uh twisty cables on an older style

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telephone that you always seem to hit stuff with as you moved around the

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room no while voice coils are indeed

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coils of wire the term is typically used

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to refer to one of two things the wires

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that actuate the ARM of a hard drive or

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the wires that make your speakers go bum

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you know both of those applications benefit from the main strengths of voice

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coils extreme accuracy and high movement

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speed you see voice coils move by using

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something called the Lorent Force which is created by placing a coil of wire in

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a fixed magnetic field when current is

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put through the coil it turns into an electromagnet making it either be

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repelled or attracted to the fixed magnetic field giving you a force this

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force can actually be quite strong

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meaning that voice coils can speed up or

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slow down extremely quickly speakers for

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example can accelerate at rates in the ballpark of 800 m/s squared or 80

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G's put into context that is 16 times

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the ex acceleration required to make you lose Consciousness 27 times quicker than

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a space shuttle launch and 21 times faster than my

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Lamborghini but how exactly does that make your speakers and your microphones

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work well for a microphone as we've

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covered in more depth here there's a membrane that moves back and forth as

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sound waves hit it these vibrations are turned turned into an electrical signal

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as a coil of wire on the back of the diaphragm moves over a magnet to turn

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this electrical signal back into sound the process is reversed so the

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electrical signal goes into the coil which moves the speaker to create your

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sweet sweet beads and it's the extraordinary

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acceleration and precision that we mentioned before that makes it possible

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for speakers to produce such a wide variety of sounds on demand what about

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computer hard drives then well you can learn more about them in an upcoming

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video because we realized we haven't actually done one yet but in a nutshell

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on one side of the ARM that hovers over

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the spinning disc like a record needle is the head which is responsible for

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reading or writing data on the platter

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and then on the other side is a voice coil this this coil of wire is

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surrounded by a permanent magnet that yada yada okay giving you everything

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that you need to get your Loren force on

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so to move the ARM current flows through the coil creating a force that causes it

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to Pivot then just before the ARM of the

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hard drive reaches its desired location the current's Reversed bringing it to a

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stop exactly exactly where it needs to

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be in fact thanks to this Lightning Fast

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deceleration the arms of hard drives are able to be positioned within a millionth

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of an inch or one for thousandth of a

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human hair wow I got like five so now

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you might be thinking why not just use voice coils for everything that needs to

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move why don't we replace the Pistons in a car or use one to throw a ball for the

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dog well here come the

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downsides excessive magnetic for force and excessive heat are kind of problems

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if you make a magnet too large it can be

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difficult to tame the magnetic field it generates I mean a massive voice coil

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wouldn't be that great if it ripped all the fillings out of your teeth or more

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realistically like not in a cartoon wiped the data off of everything in a

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10t radius also anything that has a

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bunch of current going through a wire will tend to be a bit uh

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toasty if you've ever had your speakers emit the magic black smoke that's most

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likely why but this also doesn't mean that the applications of voice coils are

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limited to our two examples from before

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one of my favorite uses for them that you'll hopefully see more of in coming

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years are voice coil actuated camera

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stabilizers these are similar to gimal

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image stabilizers but instead of using several rotating Motors they use you

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guessed it voice coils to position the camera you got it again extreme speed

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and accuracy this thing huh wow uses

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badass voice coils and is so fast and so

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precise that it can create two 30fps

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videos from a single 60fps camera

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repositioning the camera between each frame to give the illusion that there

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are actually two separate cameras pretty

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cool so to say that I'm amped to see where we're headed as they continue to

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develop voice coil technology would be an understatement though I can't say

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that I have my hopes up about a new speaker that will make Nickelback sound

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any more palatable do you enjoy your freelance

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about a section so thanks for watching guys like dislike leave a comment with

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video suggestions or get subscribed in fact you can do subscribing in addition

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to all those other things do them all wait no don't like and dislike like

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