Electric discharge
Electric discharge describes any flow of electric charge through a gas, liquid or solid. Electric discharges include:
- Electric glow discharge
- Electric arc
- Electrostatic discharge
- Electric discharge in gases
- Leader (spark)
- Partial discharge
- Corona discharge
- Vacuum arc
- Townsend discharge
- Dielectric barrier discharge
Applications
The properties and effects of electric discharges are useful over a wide range of magnitudes. Tiny pulses of current are used to detect ionizing radiation in a Geiger–Müller tube. A low steady current can be used to ilustrate the spectrum of gases in a Gas-filled tube. A neon lamp is an example of a gas-discharge lamp, useful both for illumination and as a voltage regulator. A flashtube generates a short pulse of intense light useful for photography by sending a heavy current through a gas arc discharge.
Electric discharges can convey substantial energy to the electrodes at the ends of the discharge. In electric discharge machining, multiple tiny electric arcs are used to erode a conductive workpiece to a finsished shape. Arc welding is used to assemble heavy steel structures, where the base metal is heated to melting by the heat of the arc. An electric arc furnace sustains arc currents of tens of thousands of amperes and is used for steelmaking and production of alloys and other products.