An experimental investigation was conducted to determine the effect of sample configuration on the alkali metal thermal-toelectric converter (AMTEC) electrode/electrolyte characteristics measurements in a sodium exposure test cell. Two electrode/ electrolyte configurations (tube and disk) were tested to determine if there was a difference in the characteristics determined from the measurements. It was demonstrated that the configuration of the sample had little effect (similar to15%) on the measurements at typical AMTEC operating temperatures. Electrochemical impedance spectroscopy and controlled potential current-voltage curve techniques were used to determine these characteristics.