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"Veritasium" (YT) - "The Big Misconception About Electricity" ?
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adx:

--- Quote from: SandyCox on January 10, 2022, 12:56:18 pm ---If COMSOL change the resistance of the bulb to 718 Ohm then half the battery voltage will appear across the bulb after 3.3 ns.

--- End quote ---

I was loosely considering asking that (or that without knowing the match) on their blog, I'd be interested in the effect on radiation loss.

They also link an article on modelling skin effect, would be my next request. At some point they'd want me to buy a seat! That would have to be a very short conversation.

BTW I've been looking at OpenEMS and Meep as free modellers. They don't have the all the CAD niceness, but would suit something like this.
adx:

--- Quote from: Sredni on January 10, 2022, 01:10:29 pm ---
--- Quote from: SandyCox on January 10, 2022, 12:28:00 pm ---
--- Quote from: Sredni on January 10, 2022, 12:00:03 pm ---Can you zoom in in the first ten nanoseconds, to see how well they match?

--- End quote ---
We can’t expect them to match. Transmission line theory cannot be used to model the initial 1m/c delay. I mentioned this in my previous posts.

--- End quote ---

We both know they do not match. I just wanted to see if you can show just the first ten nanoseconds to see how much they do not match.
(This, as well has been debated in previous posts - but it would be nice to see it graphically)

--- End quote ---

I wonder if the 1m/c is cumulative over every reflection. I suppose it has to be.
SandyCox:

--- Quote from: adx on January 10, 2022, 01:34:56 pm ---
--- Quote from: Sredni on January 10, 2022, 01:10:29 pm ---
--- Quote from: SandyCox on January 10, 2022, 12:28:00 pm ---
--- Quote from: Sredni on January 10, 2022, 12:00:03 pm ---Can you zoom in in the first ten nanoseconds, to see how well they match?

--- End quote ---
We can’t expect them to match. Transmission line theory cannot be used to model the initial 1m/c delay. I mentioned this in my previous posts.

--- End quote ---

We both know they do not match. I just wanted to see if you can show just the first ten nanoseconds to see how much they do not match.
(This, as well has been debated in previous posts - but it would be nice to see it graphically)

--- End quote ---

I wonder if the 1m/c is cumulative over every reflection. I suppose it has to be.

--- End quote ---
According to transmission line theory, the bulb current is constant between t=0ns and t=100ns. So, the COMSOL simulation is delayed by 3.3ns compared to transmission line theory. I attach the full explanation.

Edit: I updated the note which now includes a comparison over the first 500ns.
SandyCox:
If the bulb is properly matched to the line (R=2Zo), we will get 25% of full power in the bulb after 3.3 ns. I wonder how QED explains this. Is the probability time dependent?
Sredni:
First 15 nanoseconds



First 5 nanoseconds, where the magic happens:



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