Magnetic core is a material with high magnetic permeability that is used to confine and guide magnetic fields in various kinds of electrical, magnetic, and electromechanical devices. One of the most commonly used devices of the lot is power transformers in India. Magnetic cores within transformers increase the strength of magnetic field in an electromagnetic coil by a factor of several hundred times than what it would be without a core. It is the size and construction of the core that will indicate the power, voltage, and current that the transformer can provide. The material used to construct the core is also of prime consideration. Listed below are the most common materials used to construct transformer cores.