Bernie
Like most people, I believed that the energy used by an electric circuit flowed within the conductors (or at least on their surface, due to the skin effect).
But that's a misconception, and anyone who learned Maxwell's equations in school already has the key to guess why:
https://www.youtube.com/watch?v=bHIhgxav9LY
chebra
@codewiz I really want to see the experimental proof for this one, because I have a thought experiment to counter it. If we put the light bulb at the far end, at 1 light second away, I thinkwe would agree that it takes 1 second to light it, because even the EM field propagates at c. But what if we put the light bulb back and instead place a switch at the far end? The switch will be closed first, but we will open it less than 1s after connecting the battery, before the EM field reaches the switch
chebra
@codewiz so if the light bulb lights, doesn't that violate causality?
Bernie
@chebra Spooky action at a distance?
Bernie
@1lyaP My understanding is that only the electric field flows inside the wires, inducing a magnetic field around them, and the energy flows perpendicular to both (outwards from the generator and inwards into the load).
1lyaP
@codewiz That's a very interesting video with a clickbait header. Obviously, in the given example, energy DOES flow in wires. There are no inductivity in a circuit or smth. Cut or remove any wire and bulb will always turn off.
chebra
@codewiz seems like my question has been answered here: https://www.youtube.com/watch?v=VQsoG45Y_00 at around 30min he says that it would work the same even with an open circuit, so I guess that means the wires act like giant wireless antennas, and in my example the light bulb would light immediately and continue shining even with the distant switch open (AC) or just blip immediately and then stop (DC).
Bernie
@chebra Found a 2 year old video explaining the same principle, and visualizing how, in DC, energy actually flows _into_ the wires from the surrounding space... and also explaining where this energy ultimately comes from:
https://www.youtube.com/watch?v=C7tQJ42nGno
Bernie
@chebra Found a 2 year old video explaining the same principle, and making it more clear how, in DC circuits, energy actually flows _into_ the wires from the surrounding space... and where this energy comes from:
https://www.youtube.com/watch?v=C7tQJ42nGno
Bobinas P4G is a social network. It runs on GNU social, version 2.0.1-beta0, available under the GNU Affero General Public License.
All Bobinas P4G content and data are available under the Creative Commons Attribution 3.0 license.