Scale electrode: in the scale activity and scale pressure, with temperature changes, potential is not disorderly, small polarization, can be used as a scale measurement of the point position and potential changes of the electrode.

Working electrode: take the measurement of the reaction polarization curve on the copper electrode as an example, the working electrode (that is, the research electrode) is the place where the hydrogen evolution reaction occurs.

Reference electrode: used as a reference to measure the overpotential of other electrodes.

Additional auxiliary electrode: used to polarize the study electrode through a current. When studying the cathode process, the auxiliary electrode acts as the anode; When studying the anode process, the auxiliary electrode acts as the cathode.