Charging

Charging is the process by which an object gains electric charge. In physics, a body becomes charged when it gains or loses electrons, resulting in a net positive or negative charge. Changes in charge may occur through contact (conduction), near-field influence (induction), or separation of charges via friction (triboelectric charging).

Conduction requires physical contact between a charged body and a neutral one, leading to redistribution of charges on the surfaces to reach electrostatic equilibrium. Induction involves rearranging charges within a neutral object without contact, producing opposite charges on near surfaces. Triboelectric charging results from rubbing two materials together, transferring electrons due to material properties.

Discharge is the loss of excess charge, often through a conductive path or through the air. Lightning is a natural example of rapid discharge; static electricity is a slow buildup that may discharge when a path forms.

In electronics and energy storage, charging refers to supplying energy to a device or storage element. A battery is charged by driving chemical reactions in the reverse direction; a capacitor stores energy electrostatically. Charging circuits manage current, voltage, temperature, and safety. Rates are described by current (amperes), voltage (volts), and, for batteries, the C-rate. Lithium-ion systems require protection against overcharge, overheating, and aging effects.

In legal contexts, charging is the act of formally accusing an individual of a crime. A charge is a formal allegation; prosecutors decide whether to file charges, proceed with arraignment, or drop the case.

In everyday use, charging also refers to replenishing the power of a portable device using a charger or charging station.