From: Brent Hilpert <hilpert at cs.ubc.ca> Roger Holmes wrote: I had a niggling concern about this when the suggestion to change the C was first profferred. I don't have a thorough enough understanding of the ferro-resonant principle to categorically say what the problem is but I can half-think of a few possible issues: - Because the ferroresonance principle involves the inductor working in the core saturation region, the standard resonance equation with which you calculated the new C may not be applicable. (I see you got the square of f proportion.) - If the changed LC relationship changes the circulating current in the LC circuit then the core magnetic field will also be affected, which would upset the rest of the transformer design targets. - Changing the C changes the resonant frequency in an LC circuit, as you desire to accomplish. However, the Q factor of the resonant circuit is dependant upon the ratio of L/C, so you have also changed the Q factor. I'm less sure if this would matter, as the circuit is operating at a well-fixed frequency. My remaining concern might be that even with the new C bringing the V up, the regulation function of the supply may have been lost if the transformer is no longer functioning in the regions it was designed to.