File:Kelvin water-dropper electrostatic generator.png

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Summary

Description	English: The Kelvin water dropper, an electrostatic generator invented by William Thomson, Lord Kelvin, in 1867, that works by dripping water. This drawing, appearing in many early textbooks before 1900, may be the original form of the apparatus. It consists of a water supply pipe (c, d, e) that drips two streams of water drops. Each stream falls through a cylindrical metal charging electrode (A, B) and then into a metal funnel (a, b), from which it drips to the floor. Each metal funnel is connected to the other stream's charging electrode, and to a Leyden jar capacitor (cylindrical objects sitting on ground), to store the charge. If electrode A and attached funnel a are assumed to start with a slight positive charge as shown, its electric field with attract the negative charges (ions) in the water into the drops, and each drop that falls through A will have a slight negative charge. When it collects in funnel b the charge is communicated to electrode B. This electrode will then attract positive charges into its stream of water, and each drop falling through B will have a slight positive charge. These drops collect in funnel a and transfer their charge to electrode A, thus increasing its positive charge. By this process, as the drops fall through the machine an increasing charge will build up on the electrodes, positive charge on A and a, and a negative charge on B and b.
Date	1918
Source	Downloaded 11 October 2013 from Leo Graetz 1918 Handbuch der Elektrizität und des Magnetismus, Band 1: Elektrizitätserregung und Elektrostatik, Johann Ambrosius Barth, Leipzig, Germany, p. 39, fig. 21,22 on Google Books
Author	Leo Graetz

Licensing

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