What properties are required for a reference electrode?
The major requirement for a reference electrode is that the potential does not change with time. Since the passage of current through an electrode can alter the potential, such effects are minimized for the reference electrode in the three electrode system by a) having a high input impedance for the reference electrode (thereby decreasing the current passing through the reference electrode to negligible levels) and b) using a non-polarizable electrode as the reference electrode (i.e., the passage of small currents does not alter the potential).
