Karol Pollak

Karol Franciszek Pollak (1859 to 1928) was a Polish electrical engineer, inventor and businessman, known for his contributions to the electrolytic capacitor and the diode bridge. Born in Sanok in the Kingdom of Galicia and Lodomeria, he worked as an electrician in his youth, joined the laboratory of the Patent Utilisation Company in Britain in 1883 and studied electrical engineering at Charlottenburg from 1885. He published patents under the anglicised name Charles Pollak, ran an electrical equipment works in Berlin and directed a Paris electric tramway company, but his main activity concerned chemical sources of energy, galvanic cells and batteries. He patented a way of manufacturing lead-acid batteries, founded battery factories in Frankfurt and Liesing, and licensed his designs to many battery makers. He suggested the full bridge diode rectifier circuit in 1895 and invented the electrolytic capacitor in 1896, held 98 patents, and returned to Poland in 1922 to found the Biala factory that still operates. He was sometimes called the Edison of Poland.