PTC (Positive Temperature Coeffi Cient )

PTC is a thermistor with a positive temperature coefficient and a sharp increase in resistance at a certain temperature. thermistor phenomenon or material that can be used specifically as a constant temperature sensor .

RT and RT0 indicate the resistance value at temperature T and T0, and Bp is the material constant of the material.

The PTC effect originates from the nature of the particle boundaries and interparticle boundary precipitation phases of ceramics and varies significantly with impurity type, concentration, sintering conditions, etc.

Among the thermistors that have recently entered practical use are silicon temperature-sensitive elements using silicon wafers, which are small and highly accurate PTC thermistors made of n-type silicon, where electron scattering from impurities increases with temperature and thus resistance increases.

Using the properties of PTC thermistors, thermal switches play an important role in many fields. In home appliances and industrial equipment, thermal switches are commonly used for temperature control and overheating protection. When the temperature of the equipment exceeds the safety range, the resistance value of the PTC thermistor rises sharply, triggering the switch to operate and cut off the current, thus preventing the equipment from overheating and causing accidents.

In addition to home appliances and industrial equipment, thermal switches are also widely used in the automotive field. In engine cooling systems, thermal switches can monitor the temperature of the coolant. Once the temperature is too high, the characteristics of the thermistor will cause the switch to operate, triggering the operation of the cooling system and effectively reducing the engine temperature. In addition, in the car seat heater, the thermal switch can monitor the seat temperature, and when the temperature reaches the set value, the thermal switch will cut off the power to the heating element to avoid discomfort or safety hazards caused by overheating. In the car air conditioning system, the thermal switch can monitor the temperature of the cold air supply line to ensure that the system operates within the appropriate temperature range to provide a comfortable driving environment.

In summary, the versatility and reliability of thermal switches have made them an essential key component in many electronic devices , providing an important means of temperature control and protection for a wide range of industries. Whether in the home appliance, industrial equipment or automotive sectors, thermal switches play a key role in ensuring the stable operation of equipment and systems, while improving safety and reliability.

In addition to being a heating element, the PTC thermistor can also play the role of a "switch" and has the functions of a sensitive element, a heater and a switch, and is called a "thermal switch".

When current passes through a PTC thermistor, it causes an increase in temperature, which means that the temperature of the heat emitter rises. When the temperature exceeds the Curie point temperature, the resistance value increases, which limits the increase in current. This results in a decrease in current, which in turn causes the temperature of the component to drop. As the temperature decreases, the resistance value decreases and the current in the circuit increases again, causing the temperature of the component to rise. This process is repeated so that the temperature is kept within a specific range and acts as a switch. Using this temperature resistance property of PTC thermistors, they can be used as heating sources, such as air warmers, soldering irons, clothes dryers, air conditioners, etc. In addition, it can also be used as an overheat protection in electrical appliances.