sähköpurkaantumiseen

Sähköpurkaantuminen, known in English as electrical discharge, is a phenomenon where an electric current passes through a medium that is normally an electrical insulator. This typically occurs when the electric field strength across the insulator exceeds its dielectric strength, causing the insulator to break down and become conductive. Common insulating materials include gases, liquids, and solids like air, oil, and glass, respectively.

There are several types of electrical discharges. Arc discharge is characterized by a continuous, high-current flow with a bright, hot channel. Spark discharge is a transient, high-voltage discharge that creates a brief, luminous channel. Corona discharge is a partial discharge that occurs when the electric field is concentrated at sharp points or edges, creating a faint glow and often ozone. Dielectric breakdown is a more general term for the loss of insulating properties of a material under high voltage.

Electrical discharges have various applications. They are used in lighting (like fluorescent tubes and neon signs), welding, and spark plugs in internal combustion engines. They are also fundamental to phenomena like lightning. However, uncontrolled electrical discharges can be dangerous, causing equipment damage, fires, and electric shocks. Understanding the principles of dielectric strength and discharge mechanisms is crucial in electrical engineering for designing safe and reliable systems. The breakdown voltage, the voltage at which discharge occurs, is a key parameter for insulators.