Abstract: One or more heat-conducting devices are located coincident with a bobbin that is used to form the coils of the transformer. The coil wire is subsequently wrapped around the bobbin and adjacent heat-conducting device assembly, using conventional coil winding techniques. The heat-conducting device is preferably configured to extend beyond the transformer so as to contact a heat-conducting surface, such as a ballast enclosure, when the transformer is appropriately mounted. Because the heat-conducting device is located adjacent the inner windings of the coil, which is typically the locale of the highest temperature build-up in a transformer, a highly efficient heat-transfer is achieved. Preferably, the heat-conducting device comprises one or more copper conductors, with a thin layer of insulating tape separating the copper conductors from the coil windings.