Electromagnetic Induction - Coil and Magnet

Electromagnetic induction is the process in which an electromagnetic field is induced by changing magnetic flux. A special case of electromagnetic induction is mutual inductance. It is the effect of Faraday’s law of induction for one device upon another, such as the primary coil in transmitting energy to the secondary. In some circumstances where the devices are fixed, flux is changed only by varying current. This is the reason why we can observe the induction in secondary coil when we use generator as a source of alternating voltage for the primary winding. If we use direct current in the primary winding we measure voltage in the secondary winding only for a short time when change of current is provided by a switch.