Induced current produces a secondary magnetic field that is always opposed to the primary magnetic field that induced it, an effect called Lenz’s law.

The alternating current in the coil generates an alternating magnetic field that induces an emf in the same circuit. The effect in which a changing current in a circuit induces an emf in the same circuit is referred to as self-induction.

Eddy Currents are closed loops of induced current circulating in planes perpendicular to the magnetic flux. They normally travel parallel to the coil's winding and the flow is limited to the area of the inducing magnetic field. Eddy Currents concentrate near to the surface adjacent to an excitation coil and their strength decreases with distance from the coil. Eddy Current density decreases exponentially with depth. This phenomenon is known as the skin effect. Eddy Currents are closed loops of induced current circulating in planes perpendicular to the magnetic flux. They normally travel parallel to the coil's winding and the flow is limited to the area of the inducing magnetic field. Eddy Currents concentrate near to the surface adjacent to an excitation coil and their strength decreases with distance from the coil. Eddy Current density decreases exponentially with depth. This phenomenon is known as the skin effect.

Magnetic Levitation (Maglev) Trains  Induced surface (“eddy”) currents produce field in opposite direction  Repels magnet  Levitates train Maglev trains today can travel up to 310 mph May eventually use superconducting loops to produce B-field  No power dissipation in resistance of wires! Magnetic Levitation (Maglev) Trains  Induced surface (“eddy”) currents produce field in opposite direction  Repels magnet  Levitates train Maglev trains today can travel up to 310 mph May eventually use superconducting loops to produce B-field  No power dissipation in resistance of wires! N S rails “eddy” current

Can detect the presence of metals by using a transmitter coil to create an oscillating primary magnetic field. This creates a secondary magnetic field due to eddy currents in the metal. Can detect this secondary magnetic field by using a receiver coil.