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 an Austro-Hungarian[1] chemist and inventor.[2] Later, in Hungary he used the name Just Sándor Frigyes. In 1904 with Austro-Hungarian 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.[3] Just and Hanaman received a Hungarian patent in 1904, and later US Patent 1,018,502.[1] In 1905, Just and Hanaman patented a process for producing tungsten filaments by plating carbon filaments with tungsten, then removing the carbon by heating.[4] 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.[5] It was supplanted by the drawn tungsten filament lamp, developed in 1910 by William David Coolidge.


  1. ^ a b US patent 1018502, Just, Alexander & Hanaman, Franz, "INCANDESCENT BODIEs FOR ELECTRIC LAMPS", issued 1912-02-27 
  2. ^
  3. ^ Coolidge, W. D. (1912). "Metallic Tungsten and Some of its Applications". Transactions of the American Institute of Electrical Engineers. XXXI (1): 1220. doi:10.1109/T-AIEE.1912.4768477. ISSN 0096-3860. [1]
  4. ^ Hirst, H. "Recent progress in tungsten metallic filament lamps," The Electrical Journal, Volume LXI, May 22, 1908, pages 215-216. Retrieved December 14, 2011
  5. ^ 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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