PTC is Positive Temperature Coefficient acronym, meaning is positive temperature coefficient, positive temperature coefficient of the semiconductor material or device. Usually we mentioned PTC is the correct temperature coefficient thermistor, referred to as PTC thermistor. PTC thermistor is a kind of typical model is sensitive to the temperature of the semiconductor resistor, above a certain temperature ( Curie temperature ), its resistance value with the temperature increasing step. PTC thermistor is widely used in energy saving lamp preheating start, electronic circuit overcurrent protection, motor starters and other fields.