Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>In most dual toroid setups we measure the effective capacitance to be approx 1.5 x the cap of a single toroid. You never get to 2 x cap because the lower toroid "shrouds" the upper toroid. Usually 1.5 is the gain under measured conditions. It's very common to use a smaller toroid, ie, 0.6 x dia. of larger toroid, as the lower toroid. This helps prevent corona off the top turn of the sec where the capacitance suddenly drops to 1/2 its normal value because there are no turns directly above it, only below. This effect causes a sudden potential rise and leakage at the last turn on the coil.
Dr. Resonance
I see a lot of people using a toroid on top of a toroid to help prevent spark jumps to the secondary. I have 2 questions about this. 1). Does this really work? 2). If let's say you have calculated out that you need a 8x24 toroid, what size toroid would you use if you were to use the 2 torrid setup and how would you determine or calculate that? Kevin M. Conkey