PTC Thermistors Amphenol Advanced Sensors PTC thermistors are temperature-dependent resistors manufactured from doped barium titanate and are available with transition temperatures from 60°C to +200°C. The series offers sensitivity to changes in thermal conductivity and the ability to self-regulate temperature. Typical applications for Amphenol Advanced Sensors PTC thermistors include fluid level-flow detection, self-regulating heaters, overtemperature and overcurrent protection, surge generation, and current stabilization.