Cores
The magnetic core is a key component in electrical devices such as electromagnets, transformers and inductors. Its role is to increase the strength and effect of magnetic fields produced by electric currents. The properties of the device will depend crucially on the following factors:

•  the geometry of the magnetic core.
•  the amount of air gap in the magnetic circuit.
•  the properties of the core material (especially permeability and hysteresis).
•  the operating temperature of the core.
•  whether the core is laminated to reduce eddy currents.