Ferdinand BraunBorn 6 Jun 1850; died 20 Apr 1918 at age 67.Karl Ferdinand Braun was a German physicist whosharedthe Nobel Prize for Physics in 1909 with Guglielmo Marconi for the development of wireless telegraphy. He published papers on deviations from Ohm's law and on the calculations of the electromotive force of reversible galvanic elements from thermal sources, and discovered (1874) the electrical rectifier effect. He demonstrated the first cathode-ray oscilloscope (Braun tube) in 1897, after work on high-frequency alternating currents. Cathode-ray tubes had previously been characterized by uncontrolled rays; Braun succeeded in producing a narrow stream of electrons, guided by means of alternating voltage, that could trace patterns on a fluorescent screen. |
