Apple Inc.
Coil arrangement

Abstract:

A coil arrangement for an inductive power transfer system comprising a core (32, 33) having a region of decreased permeability (34), a coil (45) associated with the core, and a tuning slug (35) which is moveable along an axis adjacent the region of decreased permeability in order to adjust the inductance of the coil arrangement, the tuning slug (35) having an effective permeability which varies along said axis.