As one of the serious natural disasters, lightning has caused countless material damage and casualties to the world every year. With the extensive application of electronic and microelectronic integrated equipment, more and more systems and equipment are damaged by lightning overvoltage and lightning electromagnetic pulse. Therefore, it is very important to solve the lightning disaster protection of buildings and electronic information systems as soon as possible, and the installation of power surge protector is an important part of safety production measures. The establishment of comprehensive and systematic lightning surge overvoltage protection can effectively reduce the lightning hazard of buildings and equipment. What are the components of the power surge protector?
The main function of the surge protector is to limit the transient overvoltage to the voltage range it can withstand, so the voltage limiting element is the core component. The basic components include discharge gap, gas discharge tube, varistor, suppression diode and other auxiliary components.
1 Discharge gap: discharge gap refers to the gap between metal objects exposed in the atmosphere. The two metal rods are connected to the power supply and the ground respectively, and they are disconnected under normal conditions. Once there is a transient overvoltage in the circuit, the discharge gap will be broken down, and part of the overvoltage charge will be introduced to the ground to avoid damage on the protected equipment due to sudden voltage rise.
2 Gas discharge tube: The gas discharge tube is made of opposite metal conductors with a certain discharge gap left in the middle. The discharge gap is filled with inert gas (Ar) and then sealed. When the voltage applied to both ends of the gas discharge tube exceeds a certain value, the discharge gap will be broken down and conductive. In order to improve reliability, trigger can also be configured.
3 Varistor: The main component of the varistor is zinc oxide, which is very sensitive to voltage. When the voltage applied at both ends exceeds the conduction threshold, the circuit will automatically turn on. Its operating characteristics are similar to the series-parallel connection of multiple PN junctions, and it can respond to transient overvoltage in a very short time. In the structural design of power supply surge protector, the selection and structure of varistor have great influence on its performance.
4 Suppression diode: The surge protector suppression diode can work in the directional breakdown area, and can respond quickly and clamp the voltage to the minimum. Therefore, it is the last level of protection of the power surge protector.