Single Phase Transformer

 Single phase transformers may be used to increase or decrease the voltage from one side of the transformer to the other. The turn ratio or number of windings on the primary and secondary sides of the device determines the change in voltage. Step-up transformers produce a secondary voltage that is larger than the primary voltage. Step-down transformers have a secondary voltage that is smaller than the primary voltage. Variable single phase transformers are devices with a setting for changing the turn ratio as needed. One-to-one transformers well known as Isolation Transformer are single phase transformers with a turn ratio of 1:1.