Electrolytic capacitors mounted on a printed circuit board. A capacitor is similar to a battery in that it is designed to store and release electrons. It has two terminals (electrodes) that connect to two metal plates separated by a dielectric (non-conducting material). However, unlike a battery, a capacitor cannot produce new electrons and must be charged. Also, a capacitor can release its charge in under a second, compared to a few minutes for a battery. For example, this is what is used to power a camera flash.