text: I roto i ngā tūāhuhu o te pūkaha hiko i te tau kotahi mano 1800, ko ngā whakamātautau a Alessandro Volta, o Michael Faraday, ko Georg Ohm me ētahi atu me te hangahanga o te waea hiko i te tau kotahi mano 1816 me te mīhini hiko i te tau 1872