Abstract: Novel electrical heater which are self-regulating as a result of appropriate combination of a constant current or constant voltage power source with a resistive heating component and a temperature-sensitive component. Preferred heaters comprise a plurality of heating units, each of which heating units comprises a reactive component, a resistive heating component, and a temperature-responsive component. Self-regulation of the heater may be achieved in a number of different ways, including the use of employing a reactive component and a temperature-responsive component which form a combination exhibiting an impedance which changes with temperature. The temperature-responsive component can for example change in dielectric constant, or in permeability or in shape, or can effect changes in the frequencies inputted to the reactive component.