Capacitors come in various shapes and sizes, but the large cylindrical capacitors typically are the ones that store enough energy to be potentially dangerous.

Aluminum and Tantalum Electrolytic capacitors can pack a lot into a relatively small volume. They’re well suited to high-voltage applications because of their relatively high maximum voltage ratings.

Aluminum electrolytic capacitors, the most commonly used for high voltage, usually look like little tin cans, with both leads extending from the bottom.