Batteries and dynamos do not create charge; they facilitate the movement of existing charges within a circuit. A battery generates a potential difference through chemical reactions that release electrons, which flow from the negative to the positive terminal, creating current. Electrons lose energy as they pass through resistive components like light bulbs and gain energy when they return through the power supply. Only electrons flow in the circuit, as protons remain fixed within atomic nuclei, contributing to the overall charge balance. The flow of electricity is driven by the need for conductors to achieve equilibrium in their electron distribution.