Alexanderson alternator. This apparatus,invented by the Swedish-US engineer Ernst Alexanderson (1878-1975),made voice radio broadcasts possible. Photograph courtesy of the Radio Corporation of America. The photograph forms part of a collection of unpublished images,dating from the 1860s to the 1920s,taken for 'The Pageant of America: A Pictorial History of the United States' (1925-1929) | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / NEW YORK PUBLIC LIBRARY / MIRIAM AND IRA D. WALLACH DIVISION OF ART, PRINTS AND PHOTOGRAPHS |
Taille de l’image : | 3425 px × 2712 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |