Dieléctricos

Dieléctricos are electrical insulators that can be polarized by an applied electric field. This means that when placed in an electric field, the charges within the dielectric material shift slightly, creating an internal electric field that opposes the external one. This property makes dielectrics useful for a variety of applications in electrical engineering and physics.

When a dielectric material is placed between the plates of a capacitor, it increases the capacitor's ability to store electrical energy. The dielectric material reduces the effective electric field between the plates, allowing more charge to be stored at the same voltage. This increase in storage capacity is quantified by the dielectric constant, a dimensionless quantity that represents the ratio of the capacitance with the dielectric to the capacitance without it.

Dielectrics also play a role in preventing electrical breakdown. In high-voltage applications, an air gap can break down and conduct electricity. By filling this gap with a dielectric material, the breakdown voltage can be significantly increased, providing better insulation. Common dielectric materials include ceramics, plastics, glass, and various oils. The specific properties of a dielectric, such as its dielectric strength (the maximum electric field it can withstand before breaking down) and dielectric loss (the energy dissipated as heat when subjected to an alternating electric field), are crucial for selecting the appropriate material for a given application.