Werner von Siemens

An artillery officer who taught himself telegraphy, Siemens founded a workshop in Berlin in 1847 with the mechanic Johann Georg Halske to build a pointer telegraph he had improved. His electrical knowledge won the contracts that mattered: the Prussian state lines, then the Indo-European telegraph from London to Calcutta. In 1866 he described the self-excited dynamo, which made generating electricity cheap enough for industry, and the company built the trade around it.