page_title: Karol Pollak
section_title: Most important inventions
hierarchical_section_title: Karol Pollak / Most important inventions
caption_attribution_description: English: Battery designed by K. Pollak Polski: Akumulator konstrukcji K. Pollaka
context_page_description: Karol Franciszek Pollak was a Polish electrotechnician, inventor and businessman.
context_section_description: His numerous inventions also cover other areas, among them: electric motors, color printing device, and a type of microphone. His main activity was related to chemical sources of energy – galvanic cells and batteries. He obtained a patent for manufacturing lead-acid batteries.
  He also has designed commutator and electrolytic rectifiers. In 1895 he was the first to suggest the use of full bridge diode rectification circuit, later known by Leo Graetz. In 1896, Pollak invented the electrolytic capacitor
caption: Battery constructed by Karol Pollak
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