PTC is the abbreviation of PositiveTemperatureCoefficient, meaning positive temperature coefficient, referring to the semiconductor materials or components with a large positive temperature coefficient.
Often we refer to PTC as Positive Temperature Coefficient Thermistor, abbreviated as PTC thermistor. PTC thermistor is a typical temperature-sensitive semiconductor resistor, over a certain temperature (Curie Temperature), its resistance value with the rise in temperature is a step increase.