> How exactly do you calculate the correct size for a PFC cap. I have an OBIT > with a 115V, 5A primary and a 10kV, 23mA secondary, thanks First input impedance of the OBIT: Zin = U/I = 115/5 = 23 Ohm Then the matching capacitor for it (100% PFC): C = 1/(w*Zin) = 1/(2*pi*f*23 Ohm) = 1/(120*3.1416*23) = 115 micro-Farad -- ************************************************* Jan Florian Wagner http://www.hut.fi/~jwagner