Leyden Jars - The "Electric Phial"
The Leyden jar originated about 1746 through the work of Dutch physicist Pieter van Musschenbroek of the University of Leyden and Ewald Georg von Kleist of Pomerania, working independently.
A Leyden jar consists of a glass jar with an outer and inner metal coating covering the bottom and sides nearly to the neck. A brass rod terminating in an external knob passes through a wooden stopper and is connected to the inner coating by a loose chain.
When an electrical charge is applied to the external knob, positive and negative charges accumulate from the two metal coatings respectively, but they are unable to discharge due to the glass between them. The result is that the charges will hold each other in equilibrium until a discharge path is provided. Leyden jars were first used to store electricity in experiments, and later as condensers in early wireless equipment.
A Leyden jar consists of a glass jar with an outer and inner metal coating covering the bottom and sides nearly to the neck. A brass rod terminating in an external knob passes through a wooden stopper and is connected to the inner coating by a loose chain.
When an electrical charge is applied to the external knob, positive and negative charges accumulate from the two metal coatings respectively, but they are unable to discharge due to the glass between them. The result is that the charges will hold each other in equilibrium until a discharge path is provided. Leyden jars were first used to store electricity in experiments, and later as condensers in early wireless equipment.
DEMONSTRATION LEYDEN JAR
How exactly, is the the charge stored in a Leyden Jar? Is it held in the metal, the glass, or somewhere else? This was a much debated question until 1749, when Benjamin Franklin performed a series of experiments using a specially designed jar similar to the example above. By charging the assembled jar, then carefully taking it apart and testing each part, Franklin showed that the charge was actually stored on the surface of the glass, not in the metal. However, modern physics tells us that this is due to a phenomenon unique to the high voltage jars. For more information click on the image above.
How exactly, is the the charge stored in a Leyden Jar? Is it held in the metal, the glass, or somewhere else? This was a much debated question until 1749, when Benjamin Franklin performed a series of experiments using a specially designed jar similar to the example above. By charging the assembled jar, then carefully taking it apart and testing each part, Franklin showed that the charge was actually stored on the surface of the glass, not in the metal. However, modern physics tells us that this is due to a phenomenon unique to the high voltage jars. For more information click on the image above.