Self-regulating electrical resistance heating element

A self regulating electrical resistance heating element comprising:

• a substrate, wherein the substrate is one of an electrically conductive surface and comprises of the electrically conductive surface, and which comprises a first electrical contact;
• a first metal oxide having one of a positive and negative temperature coefficient of resistance;
• a second metal oxide having a temperature coefficient of resistance opposite to that of said first metal oxide, wherein one of said first and second metal oxides being disposed on the electrically conductive surface and the other of the first or second metal oxides being disposed electrically in series above the selected one of said first and second metal oxide, and
• a second electrical contact being disposed on one of the first and second metal oxide which is not disposed on said electrically conductive surface such that a current passes between contacts through one of the first and second metal oxide that includes the contacts;
• at least one of said first and second metal oxide having the negative temperature coefficient of resistance comprises a dopant which is present in an amount such that in combination the first and second metal oxides provide a substantially constant combined resistance from an ambient to a predetermined operating temperature, and a substantial increase in resistance above the operating temperature;
• and
• wherein one of said first and second metal oxide having the negative temperature coefficient of resistance comprises granular particles that are deposited in one of a liquid slurry, a dispersion and a paste.