When magnetic flux linked with a coil changes, induced emf is produced in it and the induced current flows through the wire forming the coil. In 1895 , Focault experimentally found that these induced currents are set up in the conductor in the form of closed loops. These currents look like eddies or whirlpools and likewise are known as eddy currents. They are also known as Focault's current. These currents oppose the cause of their origin, therefore due to eddy currents, a great amount of energy is wasted in the form of heat energy. If core of transformer is laminated, then their effect can be minimised.