Limiting-current measurement counterelectrode

In limiting-current measurements, the counterelectrode is sometimes used as a reference electrode. In that case, the surface overpotential of the counterelectrode contributes to the recorded overpotential that is, the potential of the reference electrode is now current dependent. Unless precautions are taken (e.g., the area of the counterelectrode is much larger than that of the working electrode), a properly defined limiting-current plateau may not be obtained. 

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