Acting as an electromagnetic/ electrostatic shield, the laminate is applied between the primary and secondary winding and also earthed. The shield thus
prevents capacitive coupling between the primary and secondary winding.
Copper foil laminates are also used as replacements for copper wire in primary and secondary windings. Foil conductors have the advantage of having a greater surface area for a given cross sectional area, when compared to wire conductors. Since most of the current flowing through a conductor is on
the surface (i.e. the so called “skin effect”) and the limitations of the skin effect are most noticeable as frequencies increase, this has resulted in major use of foil laminate tapes in the production of high frequency transformers.