Patent attributes
A method for determining the deterioration of a capacitor that increases the measurement accuracy to have an improved reliability is disclosed. In this method for determining the deterioration of a capacitor, the deterioration of a capacitor including a pair of electrode bodies and electrolytic solution provided between the electrode bodies is determined by applying an AC voltage to the capacitor to measure an impedance characteristic at a frequency of the AC voltage. An inflection point appearing in the impedance characteristic due to the deterioration of the electrolytic solution is previously calculated to make comparison with an impedance value in the frequency region lower than the inflection point, thereby determining the deterioration.