If electricity can be used to create a magnet/electromagnet, why can’t a magnet be used to create electricity without it moving?
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Well the electricity has to be “moving” in order to create the electromagnet, so if you’re looking for semantic fairness, you’ll find it in that. But more specifically, it is the movement of electrons that induces an electromagnetic field, and thereby a magnet, not the mere presence of a difference in charges. Putting a battery next to a bar of iron does not make the iron magnetic. You’d need to wrap it in a coil, and then let the charge flow through that coil to do that.
It can! But it destroys the magnet.
When electricity flows through a coil to form an electromagnet, the coil resists the electricity, and that means that the electrical energy must go somewhere. As it happens, that electrical energy goes into the magnetic field. When we remove the battery, the electricity continues flowing for a split second, as the magnetic field collapsing returns its energy to us in the form of electricity.
When creating permanent magnets, we basically freeze some of the magnetic field inside of the magnetic material. If we put it inside of a coil of wire and heated it until it demagnetized, it would return its energy in the form of electricity to the coil.
But this destroys the magnet, and to make it magnetic again we’d have to do the same process over, so we have to put the energy back into the magnet – all this does is store some energy in the magnet.
You need stuff to move. Either the electrons need to move or the magnetic field needs to change (there are no “magnetic particles” the way we have electrons), either direction or strength or both.
So you can totally use a magnet to create electricity without physically moving the magnet, you just need to change the strength of the magnet. This is how transformers work.
Stuff sitting there, be it electrons or magnets, just…sits there. You need stuff changing to couple the electric and magnetic fields together.
One reason is that it is useless tech.
We have electricity. We don’t have on command magnetic forces, so we use the electricity to get what we need, a magnetic force.
The opposite can be done but we don’t have strong enough magnetic fields in nature, having no magnetic field to harvest means that a magnetic field harvesting device is useless.
We do have systems like that that are used as sensors for navigation. They transform the earth magnetic field in electrical power, and this power goes to a device that display the compass. For aircraft for example. But that’s just enough to give a North indication, not enough to power a led lamp or else.
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