Very Good !

Nothing new here. I learned this stuff 60 years ago. Just look at peoples faces when you tell them that lightening goes from the ground up.

Ohms law. 60 yrs ago they thought current traveled from Pos to neg until shockley with the invention of the SS diode/Transister proved it wrong.

 

Edited November 23, 20214 yr by Adrian123

Actually, he doesn't have it right.

Ignoring resistance, there's no electric field within the wire - that's the definition of a conductor (and if you want to be pedantic, then the inward flow he describes just offsets the energy lost in the resistance of the wire).  So if we have the battery at the bottom, bulb at the top and wires to the left and right, then one wire is +ve and the other -ve so the electric field is from right to left or vice-versa - perpendicular to the wires.  The magnetic field forms circles round the wires, so the Poynting vector is actually in the same direction as the wire.  The magnetic field is maximum at the surface of a current-carrying cylinder, and falls off linearly inside and as 1/r outside, so the while the energy really does travel through space in the fields, most of it does so very close to the wire - we might as well say it's carried by the wire!

Edited November 23, 20214 yr by lzamm

1 hour ago, Adrian123 said:

Ohms law. 60 yrs ago they thought current traveled from Pos to neg until shockley with the invention of the SS diode/Transister proved it wrong.

 

You need to help me out here. Bill Shockley was a co-inventor of the transistor in 1947. He had nothing to do with small signal (SS) diodes. Are you talking about the Schottky diode used in small signal (SS) applications? And how did that prove anything "wrong"? You have to understand that there are two things at work here...current flow and electron flow. Neither is "correct" or "wrong". They're just different. Here's a link to a very simple explaination:  https://www.nutsvolts.com/magazine/article/which-way-does-current-really-flow  .....Doug

Wait a minute..........current doesn't flow....the wire moves!  ⚡

This sound like the old thing about US Navy teaching electron flow vs current flow.  But his analysis doesn't include reactive power in AC circuits or the phase relationship between the B and E fields (though I take it that was intended, not a mistake).

 

scott s.

.

 

 

Yep, learned all that in Air Force electronic's school in the late 60s.  Remember vacuum tubes?

In one lab session we had to build a simple amplifier tube circuit.  There was a box of parts in the middle of the floor.  We had the bare chassis and had to follow the schematic to build the amplifier.

All of a sudden there was a loud pop and a flash similar to a flash bulb.  One of our students learned that you never apply B+ to the filament.

Noel

I thought you were going to link to Veritasium when I saw the topic...

 

 

 

3 hours ago, ScottB2 said:

I thought you were going to link to Veritasium when I saw the topic.

Me, too. Coincidentally, I had just watched that YouTube video last night. As a layperson with no background whatsoever in electricity or physics, I have to say that my mind was blown by the Veritasium video.

3 hours ago, ScottB2 said:

I thought you were going to link to Veritasium when I saw the topic...

 

Actually I nearly did. I watched the Veritasium video and then came across the one I did link to. Which one of the two do those of you with more knowledge than me favour? 

23 hours ago, W2DR said:

Just look at peoples faces when you tell them that lightening goes from the ground up.

 

Actually its both. The initial "streamers" go from the cloud down. When contact is made, the main flash that you see goes up. 

 

Its like Noel doing a little pee pee on a railway track. His tinkle goes down then he gets a shock traveling up his little pee pee. 😲😀

Edited November 24, 20214 yr by martin-w

23 hours ago, lzamm said:

while the energy really does travel through space in the fields, most of it does so very close to the wire

So how close would you have to be, without actually touching the wire, in order to receive a noticeable shock? Would it be in the nanometer range?

I guess I just assumed that most folks associate lightning with the "flash". And I agree, that goes up. I also agree that lightning, per se, goes down. I dunno how to explain electron movement and ionization. I tried with my son once but to no avail. I don't think I'd make a very good teacher.