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Electrical resistance
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True or False? One way to decrease the current that flows in an electrical circuit is to decrease the resistance.
Yeah! Rock on! Sounding good, guys. Mmm, but I want more guitar. I can't hear myself.
Okay, turn it up then. Yes, but actually, you should turn it down. What? You should turn it down, the resistance I mean. That's what makes the sound louder.
You should turn it down for the volume to go up? Yes. It's when the resistance gets lower, that the sound gets louder. This, you'll have to explain. Alright, like this...
Have you heard the story about the children in the light house? - Yeees... - Like... yesterday. In a lighthouse, - on an island... - We've heard it. We know it. The kids are longing. - Just like the electrons. - Exactly!
The kids are longing to cross the bridge! But there's the evil fairy, Resistantia, that came along and took away... Resistantia? Okay, this is new. Yes.
The evil fairy, Resistantia, took away one plank at a time, But what has this got to do with our guitar amp? from the bridge. Well, we have a voltage that creates a current. - You remember that? - Yeeah... But there's electrical resistance. - Resistance? - Yes, an opposition so to speak -- It's the same thing. You mean the evil fairy now?
Is it she who creates opposition? Kind of. She removes one plank at a time from the bridge. It gets increasingly difficult to get across the bridge. The flow of children slows down.
The holes in the bridge become an obstacle, so the current drops. But the kids are still yearning just as much, so the voltage is the same. Got it? We get it. The voltage is the same as before, but the opposition -- the resistance -- makes the current drop.
And the more planks she removes, the higher the resistance. And the current drops even more. But eventually, when there are no planks left, so that nobody can pass, what happens then to resistance -- is it... infinite? Yes!
And the current drops to zero! Great! And the converse is also true. When resistance goes down, the current goes up. If we fix the bridge, resistance drops, and the flow of children increases again.
But now the bridge is fixed, Hmmm. is there any way to increase the current even more? I think I know! If we increase the voltage! That's right!
If the children start longing even more. Higher voltage leads to higher current. So when you turn up the volume on the amplifier, it's not the voltage increasing. It's the resistance you're turning down. Want to take a closer look?
Ah! How did I end up here? You're a cartoon character. You can go anywhere. Now you are inside the amplifier.
Look at the wall! It's the circuit diagram. Play something! Neat, Philip. Now I lower the resistance.
The current increases, and the sound gets louder. And now I turn the resistance up. And the sound gets quieter. Can I come out now? - It's pretty hot in here. - Of course it's warm. All electrical devices get hot when they are in use: - Resistance causes heat. - Aaaaah, it's the resistance that does that!
Okay Philip, mash it! Yeah, just gonna turn it... DOWN!