Transformers are electromagnetic devices which transform alternating current (AC) electrical energy from primary to secondary side. The energy is transformed with equal frequency and approximately equal power by means of the transformer core magnetic field. Thus they provide galvanic isolation in the electrical system. The isolation transformers operate in the same way as other transformer types. But the main task is to provide the galvanic isolation in the electrical system. They can work as step-up transformer or step-down transformers but often operate with turns ratio . This means that the primary and secondary voltage values are equal. This is obtained with an same number of turns on the primary and secondary windings.