The use and merits of a semi-circular potential waveform in place of the conventional triangular waveform has been reported on the basis of computational simulations. We report the experimental application of this new method to the study of the electrochemically reversible [Ru(NH3)(6)](3+/2+) redox couple at a macroelectrode. The method is used to determine the formal potential of this redox couple. Agreement between theory and experiment is good.