A transformer can serve many important functions in prominent areas of electrical engineering.
1) In electrical power engineering, the transformers make it possible to convert electric power from a generated voltage of about 11kv (as determined by generator design limitations) to higher values of 132 kV, 220 kV,400 kV, 500 kV & 765 kV. Thus the permitting transmission of huge amounts of power along long distances to appropriate distribution points at tremendous saving in the cost of the transmission line as well as in power loss.
2) At distribution points, transformers are used to reduce this high voltage to a safe level of 400/300 volts for use in homes, office etc.
3) In electric communication, circuit transformers are used for a variety of purpose e.g., as an impedance transformation device to allow the maximum transfer of power from the input circuit to the output device.
4) In radio and television circuit input transformers, interstage transformers and output transformers are widely used.
5) Transformers are also used in telephone circuit, instrumentations circuit and control circuit.