Abstract: A method for accurately measuring the insulation resistance of a capacitor while reducing time taken for the measurement. To this end, a current calculation equation is first obtained based on an equivalent circuit of a capacitor; then, the calculation equation is modified or corrected based on the degree of coincidence between an actually measured current value m(t) and a calculated current value i(t), the former being within a charge-up region of a dielectric polarization component upon initial application of a voltage; next, the current value at a time point of chargeup termination is predicted or estimated by use of this modified calculation equation.

Abstract: A capacitor quality discrimination scheme capable of permitting accurate and reliable determination of whether or not a capacitor under inspection is acceptable in quality. To this end, a method for discriminating the quality of a capacitor based on the charge characteristic upon application of a DC voltage thereto includes determining a standardized selection value charge characteristic of the dielectric polarization component of the capacitor, and then quadratically approximating one of (i) the ratio of the capacitor's actual measured current value m(t) and its calculated current value j(t) as obtainable from the standardized selection value charge characteristic, (ii) the difference between m(t) and j(t), (iii) the difference between logarithmic values of m(t) and j(t), and (iv) a ratio of respective logarithmic values of m(t) and j(t).