d is for diode

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

0:00[unclear opening audio]

0:34Hey, Woz, what you doing?

0:36Oh, hi, Adabot.

0:37I was just adding some protection to this circuit.

0:39Interesting.

0:40Why does this circuit need protection?

0:42Well, a circuit needs to be protected for a couple of reasons.

0:44One example is if I were to connect a battery to this incorrectly,

0:47then electrical current might flow in the wrong direction

0:49and damage some of the components.

0:51Oh, no.

0:52How do you make sure that doesn't happen?

0:54Well, we use a diode.

1:00By placing a diode at the circuit's power input,

1:03we ensure that the current can only flow in one direction,

1:05the correct direction that we've designed the circuit to work with.

1:12So a diode is like a one-way street for electrons?

1:15Exactly!

1:16The electrons can only flow through the diode in one direction,

1:19and they have a really hard time going back the other way.

1:26The stripe indicates which end of the diode acts like a wall

1:28to block the electrons.

1:35Diode protector of circuits.

1:37Yes, but diodes do more than just protect circuits, Adabot.

1:40Oh, what else do they do?

1:42Well, some diodes emit light when we pass current through them.

1:45We like to call these light-emitting diodes, or LEDs for short.

1:50Maybe you've heard of them?

1:52LEDs? I love LEDs.

1:54I thought so.

1:56So that's what D stands for in LED. D stands for diode.

2:01That's right. Well, it looks like this circuit's all done. How about we go test it out?

2:08Adabot, are you coming?

2:10Sorry, Woz. I'm an electron in a diode. I only go in one direction.

2:15Ow.

2:18Ow.

2:19Oh, Adabot, let's go.