The changing AC current enters the primary coil of wire in the transformer. A magnetic field is produced that is concentrated in the iron core of the transformer. The changing magnetic field produced by the first coil is experienced by the second coil and current begins to flow in these wires as well. The second coil has many more turns of wire and offers a higher resistance to the current flow than the first coil. Therefore a low voltage enters the transformer and a high voltage exits, or vice versa.
Power is equal to the product of the voltage and the current.
If the voltage increases the current drops. A high voltage and low current exits the transformer carrying almost the same amount of power along the transmission lines that the initial low voltage and high current did. All Rights Reserved.