Is it broken beyond repair?

[Mike Sulzer]

If you push a ball up a hill, and then let it roll down the other side, is the final energy of the ball higher or lower than the initial state? It could be either, depending on whether the bottom of the hill is higher or lower on the other side. In either case, the simple description "charging" is inadequate to describe the essential physical process.

You must really hate "electret" microphones.

I don't think "charging" is such a bad description for the magnetising process. The magnetic field of a permanent magnet contains stored energy, and if the laws of thermodynamics are any good then that energy had to come from the device that was used to magnetise it.

In the case of magnetising a pickup magnet by waving a large neo magnet near it, the energy comes from the mechanical work done in pulling the neo magnet away.

[Mike Sulzer]

Finding a single word is tough, but a phrase can do. How about "induced alignment"?

I'll throw a log on the fire here: "charging" is a *first* law of thermodynamics word, implying energy in a measurable way went into or out of a system. I pay the electric company when I charge the 9v batteries from my wireless rig.
What word do we want to use for this *second* law operation, where we are describing the entropy that changes in a system? Yeah, maybe "charging", but I agree with Mike that it's an imperfect word at best, and in a physical sense, not applicable at all. Are you "charging" up a barn when you line up all the boards from a pile into the structure we recognize as a barn? Is it "discharging" when it rots and collapses, sending all the component boards into disarray? Substitute *iron* and *magnet* for boards and barn. Does it still make sense?
... after all this rant, I don't have a good word to suggest as a replacement, sorry.

[Steve Conner]

I'm pretty sure the final magnetised state has to be higher. If you multiply flux density and MMF together, the product has units of energy. The charger transfers energy to the magnet, and the charged magnet has some energy that the uncharged one didn't.

Maybe you could argue that this energy was already in the material and aligning the domains just made it visible from outside.

If you push a ball up a hill, and then let it roll down the other side, is the final energy of the ball higher or lower than the initial state? It could be either, depending on whether the bottom of the hill is higher or lower on the other side. In either case, the simple description "charging" is inadequate to describe the essential physical process.

[Mike Sulzer]

If you push a ball up a hill, and then let it roll down the other side, is the final energy of the ball higher or lower than the initial state? It could be either, depending on whether the bottom of the hill is higher or lower on the other side. In either case, the simple description "charging" is inadequate to describe the essential physical process.

You would have to look at the physics in detail to be sure. But the point is, higher or lower, the process is very different than just dumping charge into a capacitor. You have to use a field to line up the domains so that the system can drop into a local minimum in energy. Does it really matter to an intuitive understanding the process whether it is also a global minimum also?

[Steve Conner]

Well, when you dump charge into a capacitor, the electric field aligns polarised molecules in the dielectric, storing more energy than if the dielectric were air. It's tempting to see this as the dual of the magnetic "charging" process.

[kayakerca]

Surprisingly enough, I seem to be enjoying following this thread. However, it can't help but remind me of the immortal Chris Stevens quote from the 80's TV show Northern Exposure; "My student came to me with a desire to know the time and I told her how to build a watch."

[Steve Conner]

Well, how can you truly know the time if you don't understand how a watch works? And what better way to understand than building one?

[Mike Sulzer]

Well, when you dump charge into a capacitor, the electric field aligns polarised molecules in the dielectric, storing more energy than if the dielectric were air. It's tempting to see this as the dual of the magnetic "charging" process.

Storing energy in the molecules of the dielectric is simple: you can just think of it as stretching a spring in each of many little mechanical systems operating independently; that is, there is an increase in the average distance between the positive and negative charges.

From Wikipedia (Dielectric):

A dielectric material (dielectric for short) is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material as they do in a conductor, but only slightly shift from their average equilibrium positions causing dielectric polarization. Because of dielectric polarization, positive charges are displaced toward the field and negative charges shift in the opposite direction. This creates an internal electric field that reduces the overall field within the dielectric itself.^[1] If a dielectric is composed of weakly bonded molecules, those molecules not only become polarized, but also reorient so that their symmetry axis aligns to the field.

Note that the polarization (separating the positive and negative charges) is essential, but the molecules only become aligned in some materials. The energy comes out as the external field is lowered as the capacitor discharges.

There is a lot more to it than that in the magnetic case. It takes energy to align some or all of the domains (composed of groups of atoms or molecules already aligned) with the magnetic field, but then they interact, resulting in a lowering of the energy, and then it takes energy to kick them out of alignment. Different process altogether; there are no magnetic monopoles, so no magnetic charge gets separated. The process is just about alignment and dropping into a lower energy state when it is achieved. There is no easy way to understand it in detail without quantum mechanics.

[darrellcheng]

I have an '83 telecaster bridge pickup that I think has a break in one of the leads, at least that's what my multimeter tells me. I do not plan on trying to fix it, does anyone want it?