= Galvanic cell
{wiki}
A <galvanic cell> supplies electrical <work> from a spontaneous <redox> <chemical reaction> under the specified conditions. In discharge through a passive load, <oxidation> occurs at its negative <anode> and <reduction> at its positive <cathode>. Separating the reacting compartments makes the <Electrons> take an external route, where their transport can deliver useful <work>. See https://openstax.org/books/chemistry-2e/pages/17-2-galvanic-cells[Flowers et al., Chemistry 2e, §17.2: separated reactions and electrical work].
\Image[/galvanic-electrodes-daniell-paths.png]
{title=<Daniell cell> discharge: <Electron> flow outside and <ion> transport inside}
{description=Original schematic of a <zinc>/<copper> <galvanic cell> connected to a passive load. A chosen <potassium> <nitrate> <salt bridge> supplies compensating <anions> to the <anode> compartment and <cations> to the <cathode> compartment. The arrows represent charge-balance roles, not measured trajectories or relative fluxes. The bottom inventory is an ideal accounting example for one <mole> of net cell reaction.}
In the metallic external <electrical circuit>, <Electrons> move from <anode> to <cathode>, while <conventional current> goes from <cathode> through the load to <anode>. Inside the cell, net ionic <conventional current> closes the loop from the <anode> compartment toward the <cathode> compartment. Oppositely moving <cations> and <anions> can both contribute to that direction; see <electrolyte> for the signed <current density> calculation. A cell can maintain a nonzero terminal <electric potential difference> near open circuit while delivering almost no <power>; the <Daniell cell voltage and load experiment> makes this distinction concrete.
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