Popular Science: Why does the charger get sparks when plugged into the power supply?


Users who go on business trips with power adapters often notice that when the charger is plugged into a powered socket, sparks are often generated, and they feel panic for a while, worrying about whether the socket or adapter will be damaged. Recently, the newly recruited friends of the charging head network have asked questions about this phenomenon, and they think that many users often encounter similar situations in their lives. Therefore, the life class of the charging head network has started, and this phenomenon is carried out. Introduce and test whether there will be damage.


Arcing phenomenon

that sparks are generated when the charger is inserted into the socket is called arcing. Arc is a form of gas discharge . Gas discharge is divided into two types: self-sustained discharge and non-self-sustained discharge . Arc belongs to arc discharge in gas self-sustained discharge .

voltage exceeding 10V and a current exceeding 0.5Ais opened or closed in the atmosphere, a gas with extremely high temperature, high brightness and electrical conductivity will be generated in the contact gap (or arc gap). , called the arc.

For electrical appliances with contacts, since the arc is mainly generated when the contacts are connected/disconnected, the high temperature will burn the contacts and insulation, and in severe cases, even cause short-circuit between phases, electrical explosions, and cause fires, endangering personnel and equipment. security.

Why does it occur

As we all know, the power adapter adopts the national standard alloy plug, which is connected to the mains through the metal shrapnel of the socket. When the plug touches the metal shrapnel in the socket, the contact area will be small at the moment of contact, and the current will flow instantaneously, and there may be tiny sparks .


Secondly, the high temperature generated by the arc will melt and vaporize the surface of the contact and burn out the insulating material. For boards or chargers that have been used for a long time or have been unqualified, it is often seen that the connection ports or metal pins have burning traces, and it is easy to cause arcing short circuits and injuries.

The application of arc in life

Knowing that arcing is a phenomenon of gas discharge can be a disadvantage or an advantage.


Since the high temperature generated by the arc can reach more than 3000 ℃, under certain conditions, the strong and lasting gas discharge phenomenon that can be generated between the two electrodes can melt and vaporize the metal surface, so it is more common in mechanical repair shops in life. Arc is generated for welding; in addition, it is also used in the metallurgical industry, such as DC electric arc furnaces.

Summary By Tianyin Electroncis

Adapter is inserted into a powered plug-in board, due to the too small contact area, the voltage and current passing through are too large, resulting in arc generation, and what the user sees is little sparks ;

With the maturity of the production process and a number of overcurrent and overvoltage protection technologies, users do not have to worry too much about accidents.

In addition, due to the high temperature and strong light of the arc, it can be widely used in welding, melting, chemical synthesis, strong light source and space technology. It seems that all the phenomena in life can be explained scientifically. Only by observing carefully, you will definitely fall in love with this world full of many unknowns.