As a kid, I tried to see the delay between me flipping the light-switch and the light turning on.
“There must be a delay”, I thought to myself.
“Something has to travel from the switch to the light, right?”
But no matter how hard I looked, I couldn’t see any delay.
The light seemed to turn on exactly the same time I flipped the switch.
But one day, I “got it”.
It was in a science class in 9th grade.
Our teacher, Johanna, explained it:
“Think of a wire like a tube filled with marbles: when you put a marble in on one side, a marble pops out on the other side at the exact same time, with no delay.”
And suddenly it made sense.
That’s why there’s no delay!
The wire is always filled with “marbles”.
The “marbles” in a wire would be the electrons.
And a wire is always full of electrons.
Pushing one electron in at one end makes an electron pop out at the other end.
Hence, the saying:
“What goes in, must come out.”
And this actually means that the same amount of current flowing into a circuit also flows out of it…
Many of my students have a hard time wrapping their head around that.
So I’ll go through that in the next email.
Learn how to use this knowledge to build real circuits at Ohmify – a friendly and helpful community of electronics enthusiasts. Our members learn how to make electronic gadgets from scratch.
Keep On Soldering!
Oyvind @ build-electronic-circuits.com