Potentiostatgalvanostat

A potentiostat-galvanostat is a laboratory instrument capable of performing both potentiostatic (voltage-controlled) and galvanostatic (current-controlled) electrochemical measurements. In a typical three-electrode setup, the device regulates the potential of the working electrode relative to a reference electrode while controlling the current that flows between the working electrode and the counter electrode. The instrument uses feedback loops to maintain the requested condition and to measure the resulting current or potential.

In potentiostatic mode, the device acts as a voltage clamp. It maintains the specified potential at the working electrode by adjusting the output voltage applied between the counter and working electrodes. The measured current flowing through the cell is recorded as a function of time or potential, enabling techniques such as cyclic voltammetry and chronoamperometry.

In galvanostatic mode, the device acts as a current clamp. It enforces a constant current and adjusts the potential to sustain that current. The resulting potential versus time is recorded, allowing practices such as chronopotentiometry and coulometry, where charge transport or electrode kinetics are of interest.

Common configurations include a three-electrode arrangement (working, reference, and counter electrodes), with some systems offering four-electrode capabilities to reduce uncompensated resistance or to monitor separate potentials. Key components include the reference electrode for stable potential, the counter electrode to complete the circuit, transimpedance amplification for current measurement, and digital control software for setting and logging parameters.

Applications span corrosion studies, battery and fuel-cell research, electroplating, and sensor development. Potentiostat-galvanostat systems are versatile tools for characterizing electrochemical reactions, reaction kinetics, and material properties under controlled potential or current conditions.