A device used to maintain a steady adjustable potential between two electrodes by varying the current flowing between them. Potentiostatic capability is often found in galvanostats, which instead vary the potential in order to maintain a steady current.

These devices are used in electrochemistry to control chemical reactions that depend on electrical currents. Potentiostats are used in corrosion and electrodeposition studies as well as fuel cell and battery applications, as well as materials characterization