tailieunhanh - Chapter 20: History

In Chapter 4 of the first English edition of the book Portable Batteries by K. Eberts you can read: Our present knowledge of battery techniques traces back to times of four and a half thousand years ago. We can be sure that the copper vessels that were found from this time could only have been plated with gold by electrochemical means. In 1936 there was an archeological sensation. | 20 History H. A. KIEHNE EARLY BEGINNINGS In Chapter 4 of the first English edition of the book Portable Batteries by K. Eberts you can read Our present knowledge of battery techniques traces back to times of four and a half thousand years ago. We can be sure that the copper vessels that were found from this time could only have been plated with gold by electrochemical means. In 1936 there was an archeological sensation. Near to the present Baghdad in a Parther settlement that had flourished about from 250 . to 225 . an electrical element was found. A copper tube was placed in a clay vessel filled with an organic acid into which an iron rod insulated by asphalt was inserted. The element produced 5 volts and surely was not a battery of our understanding but must be accepted as a base for this technology. It might have served galvanic purposes. See Figure . For about 2000 years until 1799 the knowledge of these ancient cultures was obviously forgotten as Volta based his research on more recent knowledge on Galvanis frog leg experiment. With his work the scientific side of our branch was introduced. PRIMARY AND SECONDARY CELLS The inventor of the first usable primary battery is with full right George Leclanche whose 1868 invention used amalgamated zinc as negative electrode and a mixture of manganese dioxide and coal as positive electrode with a current collector of coal and as electrolyte a solution of ammonium chloride. Copyright 2003 by Expert Verlag. All Rights Reserved. Figure Prehistoric finds of the galvanic element from Khujut Rabuah close to Baghdad. After Alessandro Volta 1800 presented the so-called Volta cell practicable applications were wanted. First example of use of the Volta cell was the electrical telegraph invented by Sommering in 1810. Here the voltage of the Volta cell was served for the transmission of letters of the alphabet through a four-line cable from one place to another. The hydrogen development observed on the .