Dielektrisiin

Dielektrisiin refers to dielectric materials, which are insulating substances that do not conduct electric current but can be polarized by an electric field. When a dielectric is placed in an electric field, its internal charges rearrange slightly, creating a displacement of electric charges that enhances the field effects within the material.

A key property of dielectrics is their permittivity, often written as ε = ε0 εr, where ε0 is the vacuum permittivity and εr is the relative permittivity or dielectric constant. The permittivity determines how much electric energy is stored in the material. Dielectric behavior depends on frequency and temperature, as different polarization mechanisms (electronic, ionic, orientation) respond at different rates.

Dielectrics are classified by their medium: gases (including air), liquids, solids (such as ceramics, polymers, and mica), and vacuum. They are characterized by high electrical resistivity, low leakage currents, and a dielectric strength that defines the maximum electric field the material can withstand before breakdown.

Dielectric losses, described by the loss tangent tanδ, quantify energy dissipation as heat during alternating current operation. In capacitors, the dielectric increases capacitance according to C = εA/d, where A is plate area and d is separation, enabling compact energy storage. Dielectrics are also essential as insulation in cables, transformers, high-voltage equipment, and electronic substrates. Their performance depends on frequency, temperature, moisture, and material purity.