Arcing is the discharge of current that jumps a gap in a circuit or between two points. When the switching voltage and/or switching current of a reed switch is at the maximum specified limits, arcing happens and degrades the contact coating, thereby reducing life. When reed switches and reed sensors are switching high current loads, the break of the contact or release, will cause come amount of arcing depending on the current level and the type of load being switched. Contact protection circuits can minimize arcing.
An electric arc (or arc discharge) is an electrical breakdown of a gas that produces a prolonged electrical discharge. The current through a normally nonconductive medium such as air produces a plasma, which may produce visible light. An arc discharge is initiated either by thermionic emission or by field emission. After initiation, the arc relies on thermionic emission of electrons from the electrodes supporting the arc. An arc discharge is characterized by a lower voltage than a glow discharge. An archaic term is voltaic arc, as used in the phrase "voltaic arc lamp".
Techniques for arc suppression can be used to reduce the duration or likelihood of arc formation.
In the late 19th century, electric arc lighting was in wide use for public lighting. Some low-pressure electric arcs are used in many applications. For example, fluorescent tubes, mercury, sodium, and metal-halide lamps are used for lighting; xenon arc lamps have been used for movie projectors. Electric arcs can be utilized for manufacturing processes, such as electric arc welding, and electric arc furnaces for steel recycling.