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Electric conductor, usually metal, used as one of two terminals to conduct electric current through a conducting medium. A simple voltaic cell, or battery, consists of two electrodes, usually one zinc and one copper, immersed in an electrolytic solution (seeelectrolyte). When a chemical reaction occurs in the solution, electrons gather on the zinc electrode, or cathode, which becomes negatively charged. At the same time, electrons are drawn from the copper electrode, the anode, giving it a positive charge. The difference in charge sets up a potential difference, or voltage, between the two electrodes. When they are connected by a conducting wire, electrons flow from the cathode to the anode, producing a current.
This entry comes from Encyclopædia Britannica Concise. For the full entry on electrode, visit Britannica.com.