Working Principle Of Surge Protector - View Details And Quick Selection

In today's lightning protection system, surge protectors have become an indispensable part. In circuit protection solutions, lightning surge protective device is a key protection focus that electronic engineers pay special attention to, and has made an indelible contribution to ensuring the safety of electricity use. However, more and more people are using it, but not many people know about surge protection device. Today, let me show you the principle of surge protectors.

Surge is also called surge. As the name suggests, it is an instantaneous overvoltage that exceeds the normal working voltage. Surge protectors, also called lightning arresters, are electronic devices that provide safety protection for various electronic equipment, instruments, and communication lines. When a spike current or voltage suddenly occurs in an electrical circuit or communication line due to external interference, the surge protector can conduct and shunt in a very short time, thereby avoiding damage to other equipment in the circuit caused by the surge. In essence, a surge is a violent pulse that occurs in just a few millionths of a second.

The principle of surge protector is that in normal state, it is in a high resistance state in the circuit, which is equivalent to an open circuit; when the main circuit circuit has an instantaneous overvoltage, such as a lightning strike, the surge is equivalent to a low resistance state in the instantaneous overvoltage state, and it will instantly discharge the surge current and limit the surge voltage.

There are two commonly used components, namely the discharge gap and the gas discharge tube.

Discharge gap (also known as protection gap): It is generally composed of two metal rods separated by a certain gap exposed to the air, one of which is connected to the power phase line L1 or the neutral line (N) of the required protection equipment, and the other metal rod is connected to the ground line (PE). When the instantaneous overvoltage strikes, the gap is broken down, and part of the overvoltage charge is introduced into the earth, avoiding the voltage increase on the protected equipment.

Gas discharge tube: It is composed of a pair of cold cathode plates separated from each other and encapsulated in a glass tube or ceramic tube filled with a certain inert gas (Ar). In order to increase the triggering probability of the discharge tube, there is also a triggering agent in the discharge tube. This type of gas-filled discharge tube has two-pole type and three-pole type.

So the principle of the surge protector is that at the moment of the surge, the instantaneous overvoltage of the surge breaks through the gap or gas discharge tube, and the overvoltage is introduced into the ground to protect the equipment.