An eddy current is an electrical current induced in a piece of metal due to the relative motion of a nearby magnet. Any time a magnet passes a metallic object, its magnetic field induces an electric current, which swirls around near the surface of the metal like an eddy in a river. This electric current creates its own magnetic field, which opposes the motion of the magnet.Continue Reading
Eddy currents are responsible for some remarkable effects when properly utilized. The opposing magnetic fields produced by eddy currents can result in marked slowing of the motion of a magnet, even when it is otherwise in free fall. A strong magnet dropped through a thick copper tube, for instance, falls far more slowly than it would under the influence of gravity alone.
This effect is only observed when magnets move near metals, not nonmetals. This is because of the nature of the metallic bonds in solid metals, which allow for the relatively free flow of electrons between atoms. This is the same property that is responsible for the generally good electrical conductivity of metals. Because of this property, it is relatively easy for magnetic fields to start an electric current, which is just another way of saying electron movement.Learn more about Electricity
M & M Gold Exchange notes that jewelers and others have long used the same tests, including applying nitric acid and attempting to attach a magnet to a metal piece, to verify an item is made of real gold. In the United States, anything less than 10 karats is not considered real gold.Full Answer >
Permanently magnetize metal using a simple circuit touch process that includes rubbing a magnet several times on a piece of metal. It only takes a few minutes. You need four pieces of iron or steel bars, soft iron, and a horseshoe magnet or two bar magnets.Full Answer >
A dynamo generates electricity by using a magnetic field to imbue wires with an electric current. According to the Edison Tech Center, this process generates a direct current that can then be fed down the wires to an alternator for conversion to an alternating current; these alternators are sometimes known as generators.Full Answer >
A faradic current is an alternating, asymmetric current that stimulates muscles throughout its nerve, according to the University of Buffalo. A galvanic current is a term mostly used in medicine meaning a direct current of steady flow.Full Answer >