Surge protector, also known as lightning protection, lightning arrester, is an electronic device to provide safety protection for various electronic equipment, instruments, communication lines, low-voltage electrical lines. Suitable for ac 50/60 hz, rated voltage 380 v power supply system or a photovoltaic system, the indirect lightning and thunder and lightning directly affect or other transient over voltage surge protection, meet the family home, the third industry and industrial field of surge protection requirements, has the relative phase, contrast, relative to the midline, midline of protected mode and their combination, etc.