Capacitors store energy in an electric field and can come in numerous sizes and types. The basic form set up of a capacitor does not vary from type to type, meaning that all capacitors have two conductors and a dielectric. The dielectric is a type of insulator that separates the two conductors.
The capacitors can come in thin films or even beads, depending on what the device is being used for. The energy in a capacitor is actually stored as electrostatic energy, which is stored between the plates in the insulator. These dielectric insulators, just like the conductors, can come in a number of forms and materials, such as glass, ceramic or paper.