A SMD/SMT package is used to protect PTC thermistors. A minimum operating temperature of -40°C should be set for the PTC thermistors. It is important that this thermistor does not operate at a temperature above 85°C. A PTC thermistor has a termination of 2. When the PTC thermistors operate, they supply 30V. The heat produced by PTC thermistors should be 400mW.