-"Elektrizität für Anfänger"!

https://www.youtube.com/watch?v=bHIhgxav9LY

Cheat: Assuming a 12 V & 3 W LED bulb which draws 0.25 A,
and a 1.5 sq mm/ AWG 16 lead (having an inherent voltage drop of 6 V /km),
the applied battery voltage would only have to be 3 600 012 V [or 3.600012 MV].

Have a nice weekend, all! :idea:

Johan

I watched this when it first came out. It's a good video, but it's a bit hand wavy with the whole physics woo. I get the Poynting vectors and everything, but everything in this video can still be explained classically by capacitive coupling of the parallel wires. Dave Jones at EEVBlog did a really good analysis/rebuttal of the video from a classical electrical engineering perspective:

https://www.youtube.com/watch?v=VQsoG45Y_00

Science Asylum made a video about this in 2019. If you haven't checked out that channel you really should. It's spectacular. Much higher quality than most physics/science Youtube channels.

https://www.youtube.com/watch?v=C7tQJ42nGno

Quote:

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Originally Posted by nova_robotics

I watched this when it first came out. It's a good video, but it's a bit hand wavy with the whole physics woo. I get the Poynting vectors and everything, but everything in this video can still be explained classically by capacitive coupling of the parallel wires. Dave Jones at EEVBlog did a really good analysis/rebuttal of the video from a classical electrical engineering perspective:

https://www.youtube.com/watch?v=VQsoG45Y_00

Science Asylum made a video about this in 2019. If you haven't checked out that channel you really should. It's spectacular. Much higher quality than most physics/science Youtube channels.

https://www.youtube.com/watch?v=C7tQJ42nGno

---

I guess what it comes down to is, nothing is as simple as you think it is.

Does all of this show a better way to do "it"? No, you've still got to have wires to set up the magnetic fields so what's the point, He's selling a product, a radio controlled switch, is that new?

Quote:

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Originally Posted by old kodger

Does all of this show a better way to do "it"? No, you've still got to have wires to set up the magnetic fields so what's the point, He's selling a product, a radio controlled switch, is that new?

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No one is selling anything. There are no radios. These are videos about electrical theory.

Quote:

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Originally Posted by old kodger

Does all of this show a better way to do "it"? No, you've still got to have wires to set up the magnetic fields so what's the point, He's selling a product, a radio controlled switch, is that new?

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The point is.....it's interesting.

Quote:

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Originally Posted by DIYSwede

Cheat: Assuming a 12 V & 3 W LED bulb which draws 0.25 A,
and a 1.5 sq mm/ AWG 16 lead (having an inherent voltage drop of 6 V /km),
the applied battery voltage would only have to be 3 600 012 V [or 3.600012 MV].

---

Surprisingly, the light will illuminate at much less voltage. There are capacitive and inductive effects at work. Think of the wires as two plates of a parallel plate capacitor, or the loop as two tightly coupled dipole antennas. Even if you cut the wires (at the farthest points) the bulb would still illuminate at perhaps a few hundred, or a few thousand volts. I suspect it would also oscillate because that's essentially a giant RLC circuit with a 0 ohm termination at each end.

Quote:

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Originally Posted by nova_robotics

Surprisingly, the light will illuminate at much less voltage. There are capacitive and inductive effects at work. Think of the wires as two plates of a parallel plate capacitor, or the loop as two tightly coupled dipole antennas. Even if you cut the wires (at the farthest points) the bulb would still illuminate at perhaps a few hundred, or a few thousand volts. I suspect it would also oscillate because that's essentially a giant RLC circuit with a 0 ohm termination at each end.

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Sure, a 12 VDC LED lamp will dimly turn on at app 8 V.
I can sorta buy that these "nearly infinitesimally long" wires could acts as dipoles and/or as a capacitance (with a pretty big serial inductance to boot).
But then - I simply can't wrap my head around getting DC to flow continously thru a cap, transformer (or an antenna),
other than for an initial, single LED blink (and then perhaps another when disconnecting the battery) - but then that's only me.
AC is a whole different ball game, though.

2 cents
Johan

Positively irrelevant to the thread, but still funny:

Attachment 41832

Waste 10 (+22 in Pt 2) more minutes of your life watching a solution to another hypothetical reasoning/ unprovable hypothesis:

https://www.youtube.com/watch?v=kTjGWG2d_aM

Quote:

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Originally Posted by nova_robotics

No one is selling anything. There are no radios. These are videos about electrical theory.

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No? what do you think the reference to a "smart switch available at this location at the end of the vid, is ? What do you think a smart phone is?

Quote:

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Originally Posted by old kodger

No? what do you think the reference to a "smart switch available at this location at the end of the vid, is ? What do you think a smart phone is?

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I think you only watched the first 15 seconds and the last 60 seconds of the video. I mean yes there's an ad for smart light switches at the end of the video, but that clearly has nothing at all to do with the rest of the video. It's a science video.