How Electricity Actually Works


In November of last year I posted a Vertasium YT vid titled "The Big Misconception About Electricity".  Well it caused quite a stir and like an arachnid had many legs many of which attempted to draw A'gonrs into the poison fangs!

Well, here is the follow-up to that original vid which caused quite a stir in the "intellectual" community as well.

Vertasium "How Electricity Actually Works".

 

This does have implications for our audio cabling...

Regards,

barts 

128x128barts

@jea48 ,

I am going to start with a simple explanation. There are probably people much better at me in teaching this topic. However, I think some basics will move you much farther ahead:

- Electrons are charged particles. An electric field will cause the movement of charged particles. Larger the field greater the total movement.

- Moving charged particles are what causes a magnetic field

- If something is preventing the easy movement of those charges, something we lump together and call resistance, then naturally there are less overall charges moving in total in a given direction.

- The Poynting vector which represent power, is the cross product of the electric field and magnetic field. If the electric field changes polarity, the magnetic field does too, but the product always is in the same direction.  As the power is a function of electrical field and magnetic field, the power is directly related to both. No charges moving, no magnetic field, no power.

- It is better to say that power (energy) is transformed by the load, than consumed. Thermodynamics, conservation of energy. From a basic electrodynamic view, for resistance, the electrons "collide" with atoms, and give up their energy, key note, kinetic energy, which results in heat (referred to as Joule heating). However, that energy can be transformed through through the magnetic fields or electrical fields such that those electrons slow, and other accelerate (transformers, motors, energy transfer through a capacitor, etc).

The quantum mechanical view of how the electrons transfer their energy is much more complicated but really also not necessary for the discussion.

A point or two:

- A conductor, having no voltage field differential (effectively), means the electric field within the conductor is 0-small. Hence the transfer of "conduction" of energy from the electric field to the electrons happens on the surface/outside the conductor. This is also why poor conductors have a much deeper skin depth. The electric field extends into the conductor because there is a voltage field differential in the conductor.

- From above, we can ascertain that the energy is predominantly transferred outside the wire, not in the wire.

- There is energy in the moving electrons, kinetic, but the energy is predominantly in the EM field.

 

Clear as mud?

 

I gave an analogy once as electricity, fields, resistance and electrons are like modern banking and finance. Entities with real assets are the fields. The electrons are like a modern bank. They hold no actual money (energy), but they facilitate the transfer of energy (money), and they take their cut (resistance).

Energy does flow in the conductor, if it didn't the wire wouldn't get hot. Current doesn't leave and return, charge flows, current is the measurement (time) of the flow ( Quantity of charge) through a cross section of the conductor. 

It's not the electrons that flow, it's the electro-magnetic field that flows.

 

If we are going to be pedantic. Electrons don’t flow, but they have a net biased movement direction where a current exists. The total kinetic momentum (embodied energy) will be a factor of current. Energy does not flow in the conductor, but there is energy in the conductor in the form of net kinetic momentum.

EM fields don’t flow, they propagate. The energy is transferred in the EM field.

Electricity travels like Light in a wave and the voltage and current travel out of phase. Watch the video it Cool 😎 as they go where few have to explain. Still there is much we do not know🤷‍♂️

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