INSIDE THE LEYDEN JAR

The earliest example of a capacitor is the Leyden jar. This device was invented to store a static electric charge in conducting foil that lined the inside and outside of a glass jar. The jar was created by Ewald von Kleist and Pieter van Musschenbroek, both working independently during the early 1740s. Musschenbroek was a teacher at the University of Leiden in The Netherlands, and so named this device the Leyden jar. The glass jar housed two sheets of foil that acted as conductors – one on the outside of the jar and the other lining it. A metal chain connected to an iron rod extended through a wooden lid with a ball at the end. When a charge was applied to the conductors, the electrons were temporarily trapped and stored.