Three electrolytic capacitors with capacitance values of 2200 microfarads, 1000 microfarads and 470 microfarads. The arrows on the canisters are pointing to the capacitors' negative ends. 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. This is used to power a camera flash, for example.