PTCTZ SMD PTC Thermistors Vishay / BC Components PTCTZ SMD PTC Thermistors for overload protection are ideal for pick-and-place circuit assembly. PTCTZ thermistors have a low mounting height and small ceramic diameter for faster response. This Vishay thermistor series also features low heat transfer to substrate. PTCTZ devices provide overload protection in telecom and general industrial and automotive applications.