Ceramic heater

A ceramic heater as a consumer product is a space heater that generates heat using a heating element of PTC (Positive Temperature Coeffient) ceramic.

Ceramic heaters are usually portable and typically used for heating a room or small office, and are similar to metal-element fan heaters.

PTC ceramic material is semi-conductive and when voltage is applied to it, the power decreases quickly as it reaches a certain temperature according to the particular composition of the ceramic. This means its temperature is self-regulating.

The ceramic elements are in contact with aluminium fins, thereby heating the fins up. A fan blowing across the fins heats the air.

Electric heating elements made of resistance wire also have a positive temperature coefficient of resistivity, but do not increase their resistance enough to be self-regulating; they are typically used with the wires red-hot. The ceramic, on the other hand, increases its resistance sharply at the Curie temperatures of the crystalline components, typically 120 degrees Celsius, and remains below 200 degrees Celsius, providing a significant safety advantage.

...
Wikipedia