PTCthermistorit

PTC thermistorit, also known as positive temperature coefficient thermistors, are a type of thermistor whose resistance increases significantly with increasing temperature. This behavior is distinct from NTC (negative temperature coefficient) thermistors, where resistance decreases with increasing temperature. PTC thermistors are typically made from ceramic or polymeric materials. Their resistance-temperature characteristic is not linear, often exhibiting a sharp increase in resistance within a specific temperature range, known as the switching temperature.

The primary application of PTC thermistors is in overcurrent protection. When a current flows through a PTC thermistor, it generates heat. If the current exceeds a certain threshold, the thermistor's temperature rises above its switching temperature, causing its resistance to rapidly increase. This high resistance effectively limits the current, protecting the connected circuit from damage. Once the fault is cleared and the temperature drops, the PTC thermistor's resistance returns to a low state, allowing the circuit to resume normal operation. They are commonly found in power supplies, motors, and battery packs.

Another use for PTC thermistors is in self-regulating heating applications. Their ability to increase resistance at higher temperatures naturally limits the heat output, preventing overheating. This makes them suitable for applications like heating elements in small appliances, automotive de-icing systems, and heat tracing cables. The material composition and manufacturing process determine the specific switching temperature and resistance characteristics of a PTC thermistor, allowing for a range of applications with different temperature requirements.