Abstract: A low-voltage self-regulating heating device (200) for operation with supply voltages in the range of 0.1-12 volts having first and second layers (104, 106) of material, at least one of which is PTC material interposed between a first electrode (102) and a second electrode (108). Also a high-voltage self-regulating heating device (300) for operation with supply voltages above 240 volts having first and second layers (104, 106) of material, at least one of which is PTC material interposed between a first electrode (102) and a second electrode (108).