Läpilyöntijännitys

Läpilyöntijännitys, also known as dielectric breakdown voltage, is the maximum electric field strength that a material can withstand without losing its insulating properties. When the electric field applied across an insulating material exceeds its läpilyöntijännitys, the material undergoes dielectric breakdown, becoming conductive. This phenomenon is crucial in the design and application of electrical insulators, cables, and electronic components, as it determines the voltage limits they can safely operate under.

Dielectric breakdown can occur through several mechanisms, including electronic breakdown, avalanche breakdown, and thermal breakdown. Electronic breakdown involves the acceleration of free electrons within the material to energies sufficient to ionize atoms, creating more free electrons and thus a cascade effect. Avalanche breakdown is similar but often initiated by impurities or defects in the material. Thermal breakdown occurs when excessive current flow due to imperfections generates heat, which can degrade the insulator and further reduce its resistance to current.

The läpilyöntijännitys of a material is influenced by factors such as its chemical composition, physical structure, temperature, humidity, and the presence of impurities or defects. It is typically measured in volts per unit thickness, such as volts per millimeter (V/mm) or kilovolts per millimeter (kV/mm). Materials with high läpilyöntijännitys are desirable for high-voltage applications where reliable electrical insulation is paramount. Understanding and controlling läpilyöntijännitys is essential for ensuring the safety and performance of electrical systems.