The capacitor is the modern version of the Leyden jar. Like the jar, it consists of two conductors separated by an insulator. The insulators used can be air, a thin plastic film, or a coating of oxide on the metallic surface. One use of a capacitor is to store the energy needed to fire a flash lamp on a camera. A battery-powered circuit slowly charges the capacitor. When the flash lamp is triggered the capacitor’s energy is quickly transferred to the lamp, creating a brief, intense flash of light. Capacitors are also used in electronic devices from telephones to televisions to store energy and reduce changes in voltage.