(57) A heating pad using positive temperature coefficient thermistors as a primary heat source with the thermistors being electrically and mechanically connected to electrically conductive sheets, preferably woven, with dielectric material preferably separating the conductive sheets. A covering of dielectric material preferably is used to electrically separate the heating pad from the environment. The heating pad construction uses the conductive sheets as the primary heat transfer means from the thermistors, resulting in a relatively even heat distribution over the heating pad. The heating pad is preferably made of materials that are flexible so as to enable the pad to flex to adapt to items of different shapes to be heated by the pad.