Positive temperature coefficient (PTC) heating element is small ceramic stones with self-temperature limiting characteristics. PTC stones have fast heating response times and stability once the pre-defined reference temperature is reached. Above the reference temperature, the semi conducting and ferro-electrical properties of the ceramic are utilized to produce a rise in resistance of several orders of magnitude, and hence produce its self-limiting properties.

PTC heating element is non-flame when heating, and not easy to burn up. When the atmosphere temperature over its limited temperature, the power will be automatically reduced into the reference temperature, thus it will not have the risk of burning.

PTC stones itself is the oxide ceramic, and then it has the much longer usage life than other heating material, like resistant wires and infrared tubes.