Jännitekestävyys

Jännitekestävyys, often translated as dielectric strength or breakdown voltage, refers to the maximum electric field strength a material can withstand without undergoing electrical breakdown. When an electric field exceeding a material's jännitekestävyys is applied, the material transitions from an insulator to a conductor, often permanently damaging it. This phenomenon is crucial in the design and application of electrical and electronic components and systems.

The jännitekestävyys of a material is influenced by several factors, including its chemical composition, physical structure, temperature, humidity, and the presence of impurities or defects. Different insulating materials possess vastly different dielectric strengths. For instance, gases like air have relatively low jännitekestävyys compared to solid insulators like ceramics or certain plastics. The measurement of jännitekestävyys is typically performed by applying an increasing voltage across a sample of the material until breakdown occurs. The resulting voltage divided by the thickness of the material gives the electric field strength.

Understanding and ensuring adequate jännitekestävyys is vital for preventing short circuits, electrical fires, and equipment failure. It dictates the minimum thickness of insulation required for high-voltage applications, such as in power transmission lines, transformers, and capacitors. Conversely, in some specific applications, such as spark plugs, controlled electrical breakdown is intentionally utilized. Therefore, jännitekestävyys is a fundamental parameter for safety and reliability in electrical engineering.