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l is for led

episode 114:17

ruby, gus and billie show adabot how LEDs make light and how red, green and blue can mix into other colors.

1080p web copy from the archived upload. the source file is preserved.

automatic captions, checked for structure and key terms; corrections welcome.

read the transcript

automatic captions, checked for structure and key terms; corrections welcome.

0:02I got a right to sing the blues. I got a right to

0:08moan inside. I got a right to sit and cry

0:13down around the river.

0:17I love boxes.

0:19Whoa, what's that music?

0:21Oh, that's just Billie.

0:22Oh no, she sounds pretty sad.

0:25Yeah, don't go nuts. Billie's just got the blues again.

0:29[unclear reply]

1:05Hey, Billie, why are you so blue?

1:08I suppose that's just the way I am.

1:11So you've always been blue?

1:13Yeah, well, she's made with gallium nitride.

1:18Gallium what?

1:20Wait, what are you talking about?

1:22Well, Adabot, inside every LED is a small crystal.

1:27Really?

1:34When you connect the short leg of an LED to ground

1:37and the longer leg to positive voltage, voila!

1:41The crystal glows and the LED lights up.

1:46Very cool.

1:47So, electricity flowing through an LED's crystal creates light.

1:53But why are LEDs certain colors in the first place?

1:57The type of crystal used in an LED determines that LED's color.

2:02Oh, interesting.

2:06A red LED like me uses a type of crystal made of gallium arsenide.

2:11That's two elements, gallium and arsenic mixed together.

2:14I use an aluminum gallium crystal to get so green.

2:21And indium gallium nitride is what makes me so blue.

2:27oh so different crystals make different colored light

2:31but I've also seen LEDs

2:34that change color how do they do that well we usually call those color

2:40changing LEDs RGB LEDs hey I've got an RGB LED

2:46right here

2:46oh good let's take a closer look to see how they work

2:50we call them RGB because

2:54Because inside every one of them are three different types of crystals.

2:57One that makes red light, one that makes green light, and one that makes blue.

3:04I get it. RGB. Red, green, and blue.

3:08Exactly! And by mixing red, green, and blue, we can make pretty much any color we want.

3:15Like, say, purple.

3:20Or orange.

3:24Or even white.

3:30Wow. Thanks, guys.

3:32LEDs make a lot more sense now.

3:34You're very welcome, Adabot.

3:36LEDs are in so many electronic devices,

3:39screens, billboards,

3:41even light bulbs.

3:43Yeah. It's really important to understand how they work.

3:48Agreed.

3:49You know, Billie,

3:50you may be blue,

3:51but you light up my life.

3:54Awwww