[dinkydi]

Hi, Thanks for the responses.

GMB: I don't think "people get away [with] series connection" at all. I suggest that the capacitor that has the greatest stress is the one with the highest leakage independent of the applied voltage. The series connection gives the LOWEST maximum stress of the 2 capacitors (sorry, but this may require rereading). This is because the leakage of the leaky cap reduces and the leakage of the less-leaky cap increases until both leakages are equal. The use of resistors maintains the unbalance of the leakages, that is, one capacitor is always stressed more than the other (unless the capacitors are perfectly matched in the first place). That is, the use of resistors gives HIGHER maximum stress.

Craig: Thanks for the analysis reference. This analysis starts with the assumption that the capacitor voltages should be kept equal. No one has justified this assumption. It might seem reasonable at first, but I believe it is wrong. The lowest leakage occurs when the capacitor voltages are NOT balanced (in general). The reference honestly criticises its own methodology "does lead to higher, and possibly unnecessary dissipation levels in the resistors". The reference also states "the change of leakage current vs voltage follows an exponential curve" and in the end concludes that "This [voltage unbalance] leads to a self balancing situation whereby any voltage offset will reduce the leakage current difference,which in turn reduces the voltage offset." As I have said, without resistors "there is a stabilising mechanism in the system" - resistors are simply not needed and lead to higher and unbalanced capacitor leakage current.

Peter