What exactly is PTC heating technology? What does a ceramic have to do with heating? And what is a PTC resistor? When researching the topic of "heating with positive temperature coefficient", one stumbles across quite a few keywords: Heating resistor, heating ceramic, or PTC thermistor. We take a closer look at this thing called PTC and explain what it’s all about.
Due to its unique composition, the PTC resistor is an electronic component made of ceramic (barium titanate), featuring a positive temperature coefficient (=PTC). Therefore, the current always flows particularly well when the temperature is low. This is where the name "PTC thermistor" comes from. However, if the temperature rises, the resistance of the PTC increases, and less current flows. Why is that so?
PTC ceramics are composed of tiny crystals through which the electric current flows. However, if the temperature rises, so-called barrier layers form at the boundaries of these crystals. These disrupt the movement of the electrons, making it more difficult for the current to flow.
In other words, a PTC heating element works best whenever the heat dissipates particularly well. If not, its natural resistance increases, and the self-regulation sets in. This is not a bad thing, but rather a desirable safety feature! This particular physical behavior is called “PTC effect”. It makes PTC heating technology a process-safe solution for a wide range of applications.