The electrical plug is inserted into the socket and sparks are "wiped"

The moment the laptop adapter plug is inserted into the socket, there will be a "buzz" sound and sparks appear; when the mobile phone charger plug is inserted into the socket, sparks will sometimes flash out from time to time; ...

Arc generation

How did this spark "wipe" it out?

When the plug pin and the socket are inserted, the contact area is small, and there is a small gap between the plug and the socket, forming a loop, which generates a strong current, thereby instantaneous discharge and sparks. This is what we call arc.

Avoid arcing

Arcing is a normal phenomenon, but it can also cause a fire. In order to avoid accidents caused by arcs, how can we avoid arcs as much as possible?

1. Try to keep the plug and socket free of rust and oxidation. Before inserting the plug into the socket, please remove the dust on the plug.

2. For electrical appliances with its own switch, try to turn off the switch first, plug in the plug, and then turn on the switch. Take the notebook as an example:

Turn off the switch of the power socket first;

Connect the notebook power adapter to the power socket, and then turn on the socket switch;

Connect the DC plug end of the power adapter to the notebook.

3. Try not to use high-power electrical appliances on the same plug-in board to avoid danger.

Remark:

Arc: When the two electrodes are close to a certain distance, the continuous spark discharge caused by the breakdown of the air. Arcs are generally only generated at the moment of opening and closing. All mechanical switches generate arcs. Only materials and structures can reduce the probability and size of arcs. During the disconnection process of the switch, due to the movement of the movable contact, the switch contact gap becomes a current channel, and the dielectric (air) between the contact gaps is broken down to form an arc. The smaller the contact area between the moving and static contacts, the easier it is to produce arcs.

The main reason for the arc is that the gas (or air) contains a small amount of positive and negative ions. Under the action of an applied voltage, the ions accelerate and the number of ions increases greatly in the collision. The directional movement of these ions in the electric field forms an electric current. The current passing through the gas is accompanied by a strong heating process, so that the neutral gas molecules in the current channel are all ionized to form plasma. This arc discharge with strong sound, light and thermal effects is the process of arc formation.