Details about electrons moving in a wire, --interesting Youtube video Options

[Dave_Darling]

Very very tangential relevance to 914s, but if you ever wanted to know details about electrical flow in your electrical system...

This video focuses on what happens when you have one pair of wires connected to another pair in a Y configuration, but it also contains information on how electrons flow through a circuit--


https://www.youtube.com/watch?v=2AXv49dDQJw


It's very neat to watch the visualization of the "wave" of voltage (and similar wave of current flow) that propagates down the wire. The way he set up the measurement is very complicated, but the results are awesome.

--DD

[mskala]

Yes, this is very good at showing high-speed electrical circuit behavior without
a bunch of boring math. He didn't show this, but if there is an equivalent resistance
at the end of the wire matched to the characteristic impedance of the line, then no
reflection back will happen. When building a high-speed circuit board, any stubs
like he has, even very short ones, mess up your signal.

Another thing most people don't think about is like on really old computers, even if
you are running at 1MHz, all this back-and-forth settling is still happening, but it's
settled out before the next clock tick so it doesn't hurt anything.

[Dave_Darling]

... but if there is an equivalent resistance
at the end of the wire matched to the characteristic impedance of the line, then no
reflection back will happen.

That's actually in the next video! (IMG:style_emoticons/default/biggrin.gif)


https://www.youtube.com/watch?v=RkAF3X6cJa4


--DD