This picture in this slide shows the construction of a typical toroidal transformer. As mentioned, the core is wound from a continuous strip of high grade grain oriented silicon steel. The windings completely cover the core for best possible coupling, as well as reduced stray magnetic field. All Amgis medical transformers have reinforced insulation between the primary and secondary windings which meets all applicable UL and European standards. The transformers also have an electrostatic shield in order to reduce the leakage current as well as the capacitive coupling between primary and secondary. To meet the over load test required by the medical standards, the transformers have a resettable thermal fuse in the primary windings.