The plate capacitor
This is the next step up from a Salt water cap if you want to get in to a more complex and better perforing cap with less losses and greater efficency.

With this type of HV capasitor you will make a stack of conductors spaced out with a dielecrtic again the type and thickness of the dielectric will determin the overall capacitance value and the thickness and type of the dielectric will determine the standoff voltage, the conductor plates (thin house hold cooking foil) will need to be made smaller than the dielectric sheets to stop any corona leakage and damage to the dielectric (total cap failure), our cap was built in to a sturdy wooden box with many layers of good qulity varnish, then a vaccum was pulled on the box and it was then back filled with good qulity mineral oil to further help with HV corona suppression.

Below is the formular for calculating the values needed to build such a cap.

For our dielectric we used clear polyethelene (LDPE/HDPE)
C = capacitance in farads F
A = Surface area of one plate
D = Dielectric value of Polyethelene (LDPE/HDPE) - 2.3
d = thickness of dielectric
N =Number of plates (-1)

As you can see the cap features an over voltage builtingin spark gap, just a simple short between the two plates.
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