WEBVTT - Why Do Fluorescent Lights Make That Buzzing Noise?

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<v Speaker 1>I'm at, I'm null, I'm Ben, and we are stuff

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<v Speaker 1>you get your podcasts. Welcome to brain Stuff from How

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<v Speaker 1>Stuff Works. Hey, I'm Christian Seger, and this is brain Stuff.

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<v Speaker 1>It's fair to say that light bulbs their revolutionary invention,

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<v Speaker 1>and it's tough to imagine the modern world without them.

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<v Speaker 1>But they're not perfect. Incandescent bulbs produce way more heat

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<v Speaker 1>than they do light, and their successors, compact fluorescent lamps

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<v Speaker 1>hereafter referred to as CFLs, Well, those have their own disadvantages.

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<v Speaker 1>In office buildings around the world, the weird buzz of

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<v Speaker 1>CFL is slowly driving people into madness. So what is

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<v Speaker 1>going on with this weird noise? Anyhow, The buzz itself

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<v Speaker 1>is a product of magnet restriction, but for that to

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<v Speaker 1>make sense, we're going to need to look at how

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<v Speaker 1>these things actually work. The central element in a CFL

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<v Speaker 1>is a glass tube filled with an inert gas usually

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<v Speaker 1>are gone and mercury. The inside of the tube is

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<v Speaker 1>coated with a phosphor powder, which influences the ultimate color

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<v Speaker 1>of the light. There are electrodes at either end of

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<v Speaker 1>the tube and they're wired to an electrical circuit. And

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<v Speaker 1>still with me. When you activate the lamp, a current

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<v Speaker 1>moves through the electrodes. There's considerable voltage across the electrodes,

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<v Speaker 1>so electrons move from one end of the tube to

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<v Speaker 1>the other. This vaporizes the mercury, changing some of it

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<v Speaker 1>from a liquid to a gas. As the electrons and

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<v Speaker 1>other charged atoms move across the tube, some of them

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<v Speaker 1>collide with gaseous mercury atoms. These visions excite the atoms,

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<v Speaker 1>bumping the electrons up to higher energy levels, and when

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<v Speaker 1>the electrons return to their original energy level, they release

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<v Speaker 1>light photons. However, most of this is ultraviolet light. Before

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<v Speaker 1>it becomes useful to us, it needs to be converted

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<v Speaker 1>to visible light. This is where that phosphor powder comes in.

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<v Speaker 1>The ultraviolet light causes phosphor to fluoresce or produce visible light.

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<v Speaker 1>Manufacturers can change the color of visible light emitted by

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<v Speaker 1>using different combinations of phosphors. Here's where it gets a

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<v Speaker 1>little tricky. The current inside the tube has to be

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<v Speaker 1>limited so that it doesn't rise precipitously and trip the

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<v Speaker 1>local circuit breaker. Fluorescent lights use ballasts to keep the

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<v Speaker 1>current in check. The original ballasts for fluorescent bulbs are

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<v Speaker 1>electromagnetic devices similar to inductors. Imagine a bunch of wire

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<v Speaker 1>wound around an iron core. A change in the flow

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<v Speaker 1>of alternate currents through the inductor creates a magnetic field.

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<v Speaker 1>This field also changes, creating a changing voltage in the wire,

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<v Speaker 1>slowing the currents flow. So a ballast is useful because

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<v Speaker 1>it prevents fluorescent lights from well blowing things up. Think

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<v Speaker 1>of it like a break in a car, except well,

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<v Speaker 1>I guess okay, it can stop small explosions. Breaks and

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<v Speaker 1>cars can also stop small explosions. Never mind. The point

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<v Speaker 1>is that the ballast can also make that buzzing noise

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<v Speaker 1>through an effect called magnetostriction. This happens when the magnetic

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<v Speaker 1>field produced by the ballast physically squeezes that iron core.

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<v Speaker 1>In the United States, the light is operating at sixty hurts.

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<v Speaker 1>Thanks to magnetostriction, the core can be squeezed and released

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<v Speaker 1>at twice that rate. A hundred and twenty hurts, creating

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<v Speaker 1>the buzz, known and often hated by office workers around

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<v Speaker 1>the world. Now for the next question, how do you

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<v Speaker 1>get rid of the buzz? Well, one of the simplest

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<v Speaker 1>solutions can be to replace the bulb itself. If you

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<v Speaker 1>have an older fluorescent light, you may want to replace

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<v Speaker 1>the ballast, But keep in mind that if the device

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<v Speaker 1>begins to fail again, the buzz is going to return.

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<v Speaker 1>And that annoying buzz is not the only thing people

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<v Speaker 1>hate about compact fluorescence. The odd colors can give people headaches,

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<v Speaker 1>and the mercury inside can pose some serious health risks. Luckily,

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<v Speaker 1>there's some good news. We're not stuck choosing between inefficient

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<v Speaker 1>incandescent bulbs and humming fluorescent ones. Instead, we can use

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<v Speaker 1>l E ED bulbs. L E D bulbs may well

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<v Speaker 1>be the light bulbs of the future, but that's a

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<v Speaker 1>story for a different thing. Check out the brain stuff

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<v Speaker 1>channel on YouTube, and for more on this and thousands

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<v Speaker 1>of other topics, visit how stuff works dot com.