In 1867, Werner von Siemens described a dynamo without permanent magnets (independently invented also by Charles Wheatstone), and Siemens became the first company to build such devices.
Werner von Siemens described a dynamo without permanent magnets (independently invented also by Charles Wheatstone). This was in 1867. Siemens became the first company. This was in 1867. This was to build such devices.