Leyden-jar definition

An early form of capacitor consisting of a glass jar lined inside and out with tinfoil and having a conducting rod connected to the inner foil lining and passing out of the jar through an insulated stopper.

A condenser for static electricity, consisting of a glass jar with a coat of tinfoil outside and inside and a metal rod connecting with the inner lining and passing through the lid.

An early device for storing electric charge that uses the same principle as a modern capacitor . It consists of a glass jar with conductive metal foil covering its inner and outer surfaces, with the glass insulating these surfaces from each other. The inner surface is charged (by an external source) through an electrode penetrating the top of the jar; the inner and outer foil layers can then hold an equal and opposite charge.