of Germany
Born 27 April 1845 in Aschaffenburg.
Died 6 January 1904 in Biesdorf.
Friedrich Heinrich Philipp Franz von Hefner-Alteneck was a German electrical engineer and one of the closest aides of Werner von Siemens. He invented the Hefner lamp, which provided the measure of luminous intensity used in some countries. The measure was called the Hefnerkerze (HK). The Hefnerkerze was superseded in the 1940s by the modern SI unit, the candela.[1]
1873 Electrical machine on display at the Deutsches Museum.