Elektrostaat

Elektrostaat, in physics also electrostatics, is the branch of physics that studies electric charges at rest and the forces and fields that arise from them. It deals with electric charges in static equilibrium, Coulomb's law, electric fields, electric potential, capacitance, and related phenomena such as dielectric response and charge distribution. The central law is Coulomb's law, F = k q1 q2 / r^2 for point charges, with the electric field E = F/q = k q / r^2. In continuous media, Gauss's law, ∮ E · dA = Q_enc/ε0, provides a powerful tool for calculating fields. The concept of potential difference V and energy U = 1/2 C V^2 are key ideas, as is capacitance C of conductors and dielectrics.

The term elektrostaat also refers to devices that generate and store static electricity, such as electrostatic generators. Historical devices include friction machines, the Leyden jar, and later Wimshurst and influence machines. These apparatuses produce high voltages with minimal current and are used for demonstrations and early experiments on discharge, insulation, and electrostatic forces.

Applications of electrostatics span many fields: capacitors in electronics, electrostatic precipitation for air purification, xerography and laser printing, electrostatic painting, and ionization-based processes.

The concept originated from experiments on electrical charging in the 17th–19th centuries, culminating in Coulomb’s quantitative law and the formulation of the theory of electric fields, later integrated into Maxwell's equations. The term derives from Greek elektron and the Latin statio, meaning stationary.