Author Topic: Veritasium "How Electricity Actually Works"  (Read 64975 times)

0 Members and 1 Guest are viewing this topic.

Offline Naej

  • Regular Contributor
  • *
  • Posts: 161
  • Country: fr
Re: Veritasium "How Electricity Actually Works"
« Reply #900 on: May 27, 2022, 07:58:48 pm »
So how does energy transfer from side of a vacuum tube diode to the other?
I thought that energy was supposed to flow around the vacuum tube?
 

Online Alex Eisenhut

  • Super Contributor
  • ***
  • Posts: 3330
  • Country: ca
  • Place text here.
Re: Veritasium "How Electricity Actually Works"
« Reply #901 on: June 02, 2022, 01:15:49 am »
Hoarder of 8-bit Commodore relics and 1960s Tektronix 500-series stuff. Unconventional interior decorator.
 

Offline Terry Bites

  • Super Contributor
  • ***
  • Posts: 2353
  • Country: gb
  • Recovering Electrical Engineer
Re: Veritasium "How Electricity Actually Works"
« Reply #902 on: June 05, 2022, 04:55:01 pm »
Some time back Dave pointed out that for most practical engineers it doesn’t matter. I'd agree with that. But it may or may not matter, it depends on the situation. It matters very much to ic designers and semiconductor physicists.

Its ok to believe in little green men, it doesn’t affect satelite launches. (or does it....)

If the electrons move under influence of the potental difference they would have only Vbat electon volts of energy and get bounced back by the first atoms in the condcutor.
It is the bounce that is observed to travel in a conductor not particles. There is the drift velocity of notional charge carriers- thats really slow. It would take at least a decade or ten before the power got from the power plant to your home using that mechanism. Whats moving in the drift are electronic irregularities in the condcutors crystal lattice. "Things" in the convential sense are not going anywhere.

The thing and the name of a thing are not the same thing.








 

Offline electrodacus

  • Super Contributor
  • ***
  • Posts: 1858
  • Country: ca
    • electrodacus
Re: Veritasium "How Electricity Actually Works"
« Reply #903 on: June 05, 2022, 05:32:06 pm »
Some time back Dave pointed out that for most practical engineers it doesn’t matter. I'd agree with that. But it may or may not matter, it depends on the situation. It matters very much to ic designers and semiconductor physicists.

Its ok to believe in little green men, it doesn’t affect satelite launches. (or does it....)

If the electrons move under influence of the potental difference they would have only Vbat electon volts of energy and get bounced back by the first atoms in the condcutor.
It is the bounce that is observed to travel in a conductor not particles. There is the drift velocity of notional charge carriers- thats really slow. It would take at least a decade or ten before the power got from the power plant to your home using that mechanism. Whats moving in the drift are electronic irregularities in the condcutors crystal lattice. "Things" in the convential sense are not going anywhere.

The thing and the name of a thing are not the same thing.

I think it matters even for the practical engineer.  Like for example shielding a circuit from electric fields.
I explained how a simple shield that removes that small current through the lamp/resistor in Dereks experiment.
It is also important to understand that energy flows through a conductor and not outside of it. So in case of a capacitor being charged energy flows into capacitor and not through capacitor.
That old vacuum diode someone used as an example is good for visualization. If the filament on that is not working it acts as a capacitor but having the filament heater it allows electrons to travel through that vacuum from one plate to the other and they (electrons / charged particles) are what transports energy.
There are no electrons traveling through that 1m of air between wires in Derek's experiment  meaning no energy travels from source to lamp/resistor outside the wire.  All energy both in transient/AC and DC phase travels through wire in Derek's experiment while he claims the opposite with zero proof.

What he claims as proof is that small current in the first 65ns that is due to energy being stored in the transmission line. Adding the electric shield I mentioned will get rid of that and yet after 65ns there will be energy flowing through lamp/resistor and obviously trough wire which is also a resistor. 

Online TimFox

  • Super Contributor
  • ***
  • Posts: 7934
  • Country: us
  • Retired, now restoring antique test equipment
Re: Veritasium "How Electricity Actually Works"
« Reply #904 on: June 05, 2022, 05:35:02 pm »
Yes, that which we call Ohm's Law is a result of the scattering of electrons by lots of things in a conductor, so that they do not achieve a high velocity from the voltage gradient along the wire.
An example calculation in  https://www.macmillanlearning.com/studentresources/college/physics/tiplermodernphysics6e/classial_concept_review/chapter_10_ccr_10_mean_free_path.pdf   gives a mean free path between scattering events for electrons in copper as 0.39 nm.
 

Offline PlainName

  • Super Contributor
  • ***
  • Posts: 6796
  • Country: va
Re: Veritasium "How Electricity Actually Works"
« Reply #905 on: June 05, 2022, 07:06:07 pm »
Quote
I explained how a simple shield that removes that small current through the lamp/resistor in Dereks experiment.

Here you go again. You make a supposition and then treat it as fact, and then build other stuff on that pseudo-fact. You suggested a simple shield that could/should do what you say. Run the experiment and then you can say it actually does it.
 

Offline electrodacus

  • Super Contributor
  • ***
  • Posts: 1858
  • Country: ca
    • electrodacus
Re: Veritasium "How Electricity Actually Works"
« Reply #906 on: June 05, 2022, 07:22:02 pm »
Here you go again. You make a supposition and then treat it as fact, and then build other stuff on that pseudo-fact. You suggested a simple shield that could/should do what you say. Run the experiment and then you can say it actually does it.

I made multiple correct predictions based on correct understanding of the subject.
If you think that the shielding I mentioned will not work it is your choice to test (run the experiment) and prove me wrong.

Derek made the experiment with all the results being correct but due to him not understanding the subject he came to wrong conclusions.
He noticed some energy flowing through lamp/resistor sooner than 65ns and he wrongly concluded that is because "energy doesn't flow in wire"
He had no idea or ignored the fact that a transmission line has capacitance (energy storage) in first video then when he found out he made a second video just mentioning that but not taking it seriously in consideration.

-Do you agree that making a cut in the wire will result in no energy transfer after the first few ns required to charge the capacitor formed by the parallel wires.
-When you also understand that shielding will get rid of that initial current through lamp/resistor but energy will still start flowing after those first 65ns you will know that energy flows through wires.

Offline abquke

  • Regular Contributor
  • *
  • Posts: 128
  • Country: us
Re: Veritasium "How Electricity Actually Works"
« Reply #907 on: June 05, 2022, 07:26:45 pm »
Has "how does noise voltage work then?" been touched on?
 

Offline electrodacus

  • Super Contributor
  • ***
  • Posts: 1858
  • Country: ca
    • electrodacus
Re: Veritasium "How Electricity Actually Works"
« Reply #908 on: June 05, 2022, 07:38:12 pm »
Has "how does noise voltage work then?" been touched on?

Can you be more specific ?  Are you talking about an isolated circuit ?
Derek's real world circuit was not isolated from external influence but that part (contribution from that) was ignored.  Was fairly small so easy to ignore.

Offline abquke

  • Regular Contributor
  • *
  • Posts: 128
  • Country: us
Re: Veritasium "How Electricity Actually Works"
« Reply #909 on: June 05, 2022, 07:39:49 pm »
Noise voltage across a bare resistor.
 

Online TimFox

  • Super Contributor
  • ***
  • Posts: 7934
  • Country: us
  • Retired, now restoring antique test equipment
Re: Veritasium "How Electricity Actually Works"
« Reply #910 on: June 05, 2022, 07:44:12 pm »
Noise voltage across a bare resistor.
The simplest model to analyze thermal noise in a resistor is to connect a capacitor in parallel with the resistor (at finite temperature) and measure the random voltage across the circuit with an ideal voltmeter.
The capacitor determines the bandwidth in the ideal circuit.
Drs. Johnson and Nyquist submitted their papers to Physical Review at the same time--it is rumored that Johnson shoved his under the door of the office at Columbia--(grad student rumor).
The two papers were published in the same issue.  See  https://web.stanford.edu/~edwin98/johnson-shot-noise-paper.pdf
 

Offline abquke

  • Regular Contributor
  • *
  • Posts: 128
  • Country: us
Re: Veritasium "How Electricity Actually Works"
« Reply #911 on: June 05, 2022, 07:47:47 pm »
Noise voltage across a bare resistor.
The simplest model to analyze thermal noise in a resistor is to connect a capacitor in parallel with the resistor (at finite temperature) and measure the random voltage across the circuit with an ideal voltmeter.
The capacitor determines the bandwidth in the ideal circuit.
Drs. Johnson and Nyquist submitted their papers to Physical Review at the same time--it is rumored that Johnson shoved his under the door of the office at Columbia--(grad student rumor).
The two papers were published in the same issue.  See  https://web.stanford.edu/~edwin98/johnson-shot-noise-paper.pdf

Exactly. A function of the bandwidth of the measurement and the absolute temperature of the resistance. So. What's the explanation that isn't elections bouncing around?
 

Online TimFox

  • Super Contributor
  • ***
  • Posts: 7934
  • Country: us
  • Retired, now restoring antique test equipment
Re: Veritasium "How Electricity Actually Works"
« Reply #912 on: June 05, 2022, 07:50:32 pm »
Noise voltage across a bare resistor.
The simplest model to analyze thermal noise in a resistor is to connect a capacitor in parallel with the resistor (at finite temperature) and measure the random voltage across the circuit with an ideal voltmeter.
The capacitor determines the bandwidth in the ideal circuit.
Drs. Johnson and Nyquist submitted their papers to Physical Review at the same time--it is rumored that Johnson shoved his under the door of the office at Columbia--(grad student rumor).
The two papers were published in the same issue.  See  https://web.stanford.edu/~edwin98/johnson-shot-noise-paper.pdf

Exactly. A function of the bandwidth of the measurement and the absolute temperature of the resistance. So. What's the explanation that isn't elections bouncing around?

"Elections"--nice Freudian slip!
 

Offline abquke

  • Regular Contributor
  • *
  • Posts: 128
  • Country: us
Re: Veritasium "How Electricity Actually Works"
« Reply #913 on: June 05, 2022, 07:58:10 pm »
 :-DD

Yeah whoops.
 

Offline Naej

  • Regular Contributor
  • *
  • Posts: 161
  • Country: fr
Re: Veritasium "How Electricity Actually Works"
« Reply #914 on: June 05, 2022, 08:14:26 pm »
Some time back Dave pointed out that for most practical engineers it doesn’t matter. I'd agree with that. But it may or may not matter, it depends on the situation. It matters very much to ic designers and semiconductor physicists.
No it never matter.
Yes, that which we call Ohm's Law is a result of the scattering of electrons by lots of things in a conductor, so that they do not achieve a high velocity from the voltage gradient along the wire.
An example calculation in  https://www.macmillanlearning.com/studentresources/college/physics/tiplermodernphysics6e/classial_concept_review/chapter_10_ccr_10_mean_free_path.pdf   gives a mean free path between scattering events for electrons in copper as 0.39 nm.
This is completely incorrect.
https://homepages.rpi.edu/~galld/publications/PDF-files/Gall-116.pdf
Indicates 39.9 nm.
He assumed that electrons scatters with atoms, while they scatter with phonons.
 

Online TimFox

  • Super Contributor
  • ***
  • Posts: 7934
  • Country: us
  • Retired, now restoring antique test equipment
Re: Veritasium "How Electricity Actually Works"
« Reply #915 on: June 05, 2022, 08:23:30 pm »
Some time back Dave pointed out that for most practical engineers it doesn’t matter. I'd agree with that. But it may or may not matter, it depends on the situation. It matters very much to ic designers and semiconductor physicists.
No it never matter.
Yes, that which we call Ohm's Law is a result of the scattering of electrons by lots of things in a conductor, so that they do not achieve a high velocity from the voltage gradient along the wire.
An example calculation in  https://www.macmillanlearning.com/studentresources/college/physics/tiplermodernphysics6e/classial_concept_review/chapter_10_ccr_10_mean_free_path.pdf   gives a mean free path between scattering events for electrons in copper as 0.39 nm.
This is completely incorrect.
https://homepages.rpi.edu/~galld/publications/PDF-files/Gall-116.pdf
Indicates 39.9 nm.
He assumed that electrons scatters with atoms, while they scatter with phonons.
Yes, there are lots of things inside a conductor to scatter electrons.
In grad school, I learned about phonons, lattice imperfections, and other defects as contributions to limiting the conductivity.
Note that, in general, alloys (which include impurities) have much lower conductivity than pure metals under normal conditions.
« Last Edit: June 05, 2022, 08:25:02 pm by TimFox »
 

Offline SiliconWizard

  • Super Contributor
  • ***
  • Posts: 14297
  • Country: fr
Re: Veritasium "How Electricity Actually Works"
« Reply #916 on: June 05, 2022, 08:25:36 pm »
But electrons don't matter anyway? ;D
 

Offline abquke

  • Regular Contributor
  • *
  • Posts: 128
  • Country: us
Re: Veritasium "How Electricity Actually Works"
« Reply #917 on: June 05, 2022, 08:32:23 pm »
"Bremsstrahlung... what? Why are you all hiding behind lead shields? I'm surely not in the path of any Poynting vectors"
 

Online TimFox

  • Super Contributor
  • ***
  • Posts: 7934
  • Country: us
  • Retired, now restoring antique test equipment
Re: Veritasium "How Electricity Actually Works"
« Reply #918 on: June 05, 2022, 08:36:37 pm »
"Bremsstrahlung... what? Why are you all hiding behind lead shields? I'm surely not in the path of any Poynting vectors"
Again, in grad school we had a visiting professor from Darmstadt.  He was giving a series of lectures on electron interactions.  Although his English was very good, he was a little nervous about his lecture and asked an American student who was fluent in German to sit in the front row, in case he had a language problem.  At one point, he asked "Wie sagt man Bremsstrahlung auf Englisch?, to which the student replied "Bremsstrahlung".
 
The following users thanked this post: Alex Eisenhut

Offline Naej

  • Regular Contributor
  • *
  • Posts: 161
  • Country: fr
Re: Veritasium "How Electricity Actually Works"
« Reply #919 on: June 05, 2022, 08:40:36 pm »
But electrons don't matter anyway? ;D
Poynting vector does not matter. Electrons, obviously, do.
 

Offline aetherist

  • Frequent Contributor
  • **
  • !
  • Posts: 621
  • Country: au
  • The aether will return. It never left.
Re: Veritasium "How Electricity Actually Works"
« Reply #920 on: June 05, 2022, 09:33:33 pm »
Some time back Dave pointed out that for most practical engineers it doesn’t matter. I'd agree with that. But it may or may not matter, it depends on the situation. It matters very much to ic designers and semiconductor physicists.
No it never matter.
Yes, that which we call Ohm's Law is a result of the scattering of electrons by lots of things in a conductor, so that they do not achieve a high velocity from the voltage gradient along the wire.
An example calculation in  https://www.macmillanlearning.com/studentresources/college/physics/tiplermodernphysics6e/classial_concept_review/chapter_10_ccr_10_mean_free_path.pdf   gives a mean free path between scattering events for electrons in copper as 0.39 nm.
This is completely incorrect.
https://homepages.rpi.edu/~galld/publications/PDF-files/Gall-116.pdf
Indicates 39.9 nm.
He assumed that electrons scatters with atoms, while they scatter with phonons.
Yes, there are lots of things inside a conductor to scatter electrons.
In grad school, I learned about phonons, lattice imperfections, and other defects as contributions to limiting the conductivity.
Note that, in general, alloys (which include impurities) have much lower conductivity than pure metals under normal conditions.
Yes, but alloys in wires do not affect the speed of the elektons (elekticity) on the surface of the wire.
« Last Edit: April 29, 2023, 05:21:40 am by aetherist »
 

Online TimFox

  • Super Contributor
  • ***
  • Posts: 7934
  • Country: us
  • Retired, now restoring antique test equipment
Re: Veritasium "How Electricity Actually Works"
« Reply #921 on: June 05, 2022, 09:36:34 pm »
Some time back Dave pointed out that for most practical engineers it doesn’t matter. I'd agree with that. But it may or may not matter, it depends on the situation. It matters very much to ic designers and semiconductor physicists.
No it never matter.
Yes, that which we call Ohm's Law is a result of the scattering of electrons by lots of things in a conductor, so that they do not achieve a high velocity from the voltage gradient along the wire.
An example calculation in  https://www.macmillanlearning.com/studentresources/college/physics/tiplermodernphysics6e/classial_concept_review/chapter_10_ccr_10_mean_free_path.pdf   gives a mean free path between scattering events for electrons in copper as 0.39 nm.
This is completely incorrect.
https://homepages.rpi.edu/~galld/publications/PDF-files/Gall-116.pdf
Indicates 39.9 nm.
He assumed that electrons scatters with atoms, while they scatter with phonons.
Yes, there are lots of things inside a conductor to scatter electrons.
In grad school, I learned about phonons, lattice imperfections, and other defects as contributions to limiting the conductivity.
Note that, in general, alloys (which include impurities) have much lower conductivity than pure metals under normal conditions.
Yes, but alloys in wires do not affect the speed of the electons (electricity) on the surface of the wire.
So tell me:  why does the alloy composition affect the conductivity of current down the wire?
 

Offline aetherist

  • Frequent Contributor
  • **
  • !
  • Posts: 621
  • Country: au
  • The aether will return. It never left.
Re: Veritasium "How Electricity Actually Works"
« Reply #922 on: June 05, 2022, 10:51:55 pm »
Some time back Dave pointed out that for most practical engineers it doesn’t matter. I'd agree with that. But it may or may not matter, it depends on the situation. It matters very much to ic designers and semiconductor physicists.
No it never matter.
Yes, that which we call Ohm's Law is a result of the scattering of electrons by lots of things in a conductor, so that they do not achieve a high velocity from the voltage gradient along the wire.
An example calculation in  https://www.macmillanlearning.com/studentresources/college/physics/tiplermodernphysics6e/classial_concept_review/chapter_10_ccr_10_mean_free_path.pdf   gives a mean free path between scattering events for electrons in copper as 0.39 nm.
This is completely incorrect.
https://homepages.rpi.edu/~galld/publications/PDF-files/Gall-116.pdf
Indicates 39.9 nm.
He assumed that electrons scatters with atoms, while they scatter with phonons.
Yes, there are lots of things inside a conductor to scatter electrons.
In grad school, I learned about phonons, lattice imperfections, and other defects as contributions to limiting the conductivity.
Note that, in general, alloys (which include impurities) have much lower conductivity than pure metals under normal conditions.
Yes, but alloys in wires do not affect the speed of the electons (electricity) on the surface of the wire.
So tell me:  why does the alloy composition affect the conductivity of current down the wire?
Yes, good question, it is so good (& obvious) that it must have kumup earlier here, i forget.
Elektons have a nett E×H field (in the nearfield & in the farfield), whereas photons don’t (at least not in the far field).
The elekton's E×H acts on elektrons, particularly on free electrons, in the wire.
The free electrons are moved, & the movement is resisted by the Cu.
The resistance ends up heating the Cu.

Every action has a reaction. Hence u would think that conductivity must affect the speed of electricity. In other words my elektons must be slowed moreso by bad conductors. This subject too must have kumup before. Praps they are slowed moreso. But praps that slowing is only say 1%, which would show, but would not show if u were not looking for it, or if u were ignoring it, or if it twernt important in the particular case under test.

For insulated wires, & on PCBs, there is a major slowing due to the insulation (insulation usually covers the whole surface), & due to the board material (in effect insulated on a half of the surface i think), hence a minor speed effect due to conductivity might not show up.
Such tests (speed of electricity) comparing metals & alloys etc would be simple -- have they ever been done?  Still thinking.

Ooops. No. The speed of electricity should be slower the better the conductor.
A good conductor acts more strongly on elektons. A poor conductor (plastic) has so little action on elektons that the elektons will not jump onto its surface, to an elekton the plastic duznt exist (unless it is in the plastic insulation of a wire)(ie whilst the elekton is propagating/flowing along the wire).


Elektons act on other elektons, hence the surface area of a wire has a saturation value, which depends on the conduction/resistance of the wire, & depends on the voltage of the source, & depends on the rate of production/supply of elektons. However, this interaction is a chicken & egg thing i suppose (as usual).
Here i need to remind myself that elekton elekticity is just one of the 3 kinds -- the others being (2) the movement of free electrons on the surface, & (3) the movement of free elektrons inside the wire.
Re that there saturation value – i wonder if it is affected by insulation. Praps knot. Still thinking.

« Last Edit: April 29, 2023, 05:20:38 am by aetherist »
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf