Ceramic PTC thermistors are used instead of conventional fuses to protect electrical devices such as motors, transformers, etc. or electronic circuits against overcurrent.Typical applications are SMPS/UPS, supplies for LED lighting and electrical power meter. They respond to inadmissibly high currents and also, if a preset temperature limit is exceeded. TDK offers leaded disk PTC thermistors up to an operating voltage range of 1000 V and SMD versions up to 230 V.