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Electromagnetic induction has found many applications, including electrical components such as inductors and transformers, and devices such as electric motors and generators. History Faraday's experiment showing induction between coils of wire: The liquid battery (right) provides a current that flows through the small coil (A) , creating a ...
Alternating electric current flows through the solenoid on the left, producing a changing magnetic field. This field causes, by electromagnetic induction, an electric current to flow in the wire loop on the right. The most widespread version of Faraday's law states:
The history of electromagnetic induction, a facet of electromagnetism, began with observations of the ancients: electric charge or static electricity (rubbing silk on amber), electric current , and magnetic attraction . Understanding the unity of these forces of nature, and the scientific theory of electromagnetism was initiated and achieved ...
An alternating current of any frequency is forced away from the wire's center, toward its outer surface. This is because an alternating current (which is the result of the acceleration of electric charge) creates electromagnetic waves (a phenomenon known as electromagnetic radiation).
Eddy currents in conductors of non-zero resistivity generate heat as well as electromagnetic forces. The heat can be used for induction heating. The electromagnetic forces can be used for levitation, creating movement, or to give a strong braking effect. Eddy currents can also have undesirable effects, for instance power loss in transformers.
Visualization of Eddy Currents Induction [3] In its most basic form — the single-element ECT probe — a coil of conductive wire is excited with an alternating electric current. This wire coil produces an alternating magnetic field around itself. The magnetic field oscillates at the same frequency as the current running through the coil.
Once the current is no longer increased and is held constant, the energy in the magnetic field is constant and no additional energy must be supplied, so the voltage drop across the windings disappears. Similarly, if the current through the inductor decreases, the magnetic field strength decreases, and the energy in the magnetic field decreases.
This field causes an electric current to flow in the wire loop by electromagnetic induction. Magnetic fields can also be used to make electric currents. When a changing magnetic field is applied to a conductor, an electromotive force (EMF) is induced, [ 21 ] : 1004 which starts an electric current, when there is a suitable path.