Alexander Just

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Alexander Just
A Just–Hanaman light-bulb, Budapest, 1906
Alexander Just as a soldier during World War I

Alexander Friedrich Just (12 April 1874 in Bremen – 30 May 1937 in Budapest) was a German/Hungarian chemist and inventor.[1] Later, in Hungary he used the name Just Sándor Frigyes. In 1904 with Croatian Franjo Hanaman he was the first to develop and patent an incandescent light bulb with a tungsten filament, made by extruding a paste of tungsten powder and a carbonaceous binder to produce a fine thread, then removing the carbon by heating in an atmosphere of hydrogen and water vapor.[2] Just and Hanaman received a Hungarian patent in 1904 and later US Patent 1,018,502. In 1905, Just and Hanaman patented a process for producing tungsten filaments by plating carbon filaments with tungsten, then removing the carbon by heating.[3] These early tungsten lamps were more efficient than a carbon filament lamp, because they could operate at a high temperature, due to the high melting point of tungsten. The tungsten was, however, so brittle that these lamps were of limited practical use.[4] It was supplanted by the drawn tungsten filament lamp, developed in 1910 by William David Coolidge.


  1. ^
  2. ^ [1] Coolidge, W.D.., "Metallic tungsten and some of its applications," Transaction of the American Institute of Electrical Engineers, Vol. XXXI, Part 1. June 25, 1912. Pages 1219-1228. Retrieved December 14, 2011
  3. ^ Hirst, H. "Recent progress in tungsten metallic filament lamps," The Electrical Journal, Volume LXI, May 22, 1908, pages 215-216. Retrieved December 14, 2011
  4. ^ Day, Lance and McNeil, Ian "Biographical dictionary of the history of technology," Routledge, 1996. Cited edition is Taylor & Francis eBook, 2005, page 290. ISBN 978-0-203-20131-2.[better source needed] Retrieved December 14, 2011.

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