Device used to isolate or to raise or lower an A. C. Voltage from its input to its output. A typical transformer may consist of two separate coils of wire wound on a magnetic steel score. When an A. C. Current passes through the input coil (primary) it produces an alternative magnetic field in the core, which in turn produces current flow in the output coil (secondary). By winding, a greater number of coil turns for the secondary winding, the input voltage is raised at the output; by using fewer secondary turns, the output voltage is lowered. An isolation transformer uses the same number of turns for primary and secondary, maintaining the same input voltage at the output while severing the electrical connection of the two coil windings.