Patent ID: 7225090

Claim:
A method of measuring the capacitance C X of a work capacitor in the presence of a parallel resistance R P , the method comprising the steps of: (a) charging the work capacitor for a selected interval of time with a constant current I C having a selected value; (b) approximating a first slope (dv/dt) 1 of the voltage waveform across the work capacitor at a first time near but after the start of the selected time interval; (c) finding the voltage V 1 across the work capacitor at the first time; (d) approximating a second slope (dv/dt) 2 of the voltage waveform across the work capacitor at a second time near but before the end of the selected time interval; (e) finding the voltage V 2 across the work capacitor at the second time; (f) computing a value of C X as a function of I C , (dv/dt) 1 , (dv/dt) 2 , V 1 and V 2 ; and (h) outputting said value of C X computed in step (f).