This lecture focus to presentation on Single Phase Transformer and it’s working process. The efficiency of electrical power transmission has been improved by means of higher voltages. The transformer can be a device for transferring power from one circuit to a new circuit without a alter in frequency. The transformer accomplishes the actual change in voltage without using moving parts, and therein is situated its great advantage. A transformer is a new static piece of apparatus with which electrical power a single circuit is transformed into electrical power of the same consistency in another circuit. It could possibly raise (step up) or maybe lower (step down) the voltage in a very circuit but with a new corresponding decrease or enhance in current.