A step transformer is a device which has a special feature like the secondary voltage is less than its primary voltage. The reduced range of the transformer varies in between 0.5kva to 500kva. It can be used for electronic equipments of all units from a bigger to smaller units. It carries power through transmission lines. Prior to the final destination the power reaches uses low voltage units. This step down transformer, which mainly are the 1-100-W power level, are use in loudspeakers in radios, TV sets and high trustworthiness equipment. They are occasionally called audio transformers, and they make replica sound-wave frequencies with negligible distortion over the bursting sound power levels.

The essential idea of a transformer is that is contains step up or step down power. Not including these transformers, allocation of our electric power over extended distance would be not possible. It consists of both primary circuit and a secondary circuit. There is no association among the two circuits, but every of these circuits enclose a winding, which associate it inductively to the further circuits. The windings are lesion onto an iron core. The iron core directs the magnetic flux engender by the current flowing in the region of the primary winding, and as a great deal as possible, also connects the secondary winding.

The proportion of the max out voltages and crest currents in the primary and secondary windings are strong-minded by the proportion of the number of revolve in the primary and secondary windings. The latter ratio is usually called the turn ratio of the transformer. If the secondary winding holds lesser rotations than the primary winding, the highest voltage in the secondary circuit is less than that of the primary circuit. This kind of transformer is termed as a step down transformer.