Core device: high voltage reed switch The common dry reed tube is mostly filled with nitrogen; the high pressure type is generally packaged in vacuum, the reed gap is widened, the glass tube is lengthened to improve the pressure resistance along the surface, and the contact is plated with ruthenium/rhodium to suppress the micro arc. The coil is energized → magnetic field is generated → the reed is closed; the coil is de-energized → the reed is disconnected by elastic rebound. The shell is encapsulated with epoxy resin in high voltage, and the creepage distance between the coil (low voltage control side) and the high voltage contact is increased to realize strong quarantine between strong current and weak current.