Build a small Marx generator.
The Marx structure consists by 4 plastic rulers glued to some CD covers as base supports.
Eight ceramic doorknobs, 470 pF@30 kV each (from HV stages of color TVs) are set in 8 stages along the rulers. HV resistors are made with 2 x 6 little 6M7@.25w in serie / stage (I know, a little too much, but my resistors are very short, so I have to put many in serie to prevent breakdown).
The gaps are made with metalic screws bought from a furniture store. The plastic rulers are flexible, so I can adjust the gaps with two white rubber gum pieces set between the rulers.
HV source: 2 paralleled DC flybacks driven with a Mazzilli driver
I am waiting some longer resistors. Until then I made a new try with some slightly longer resistors, 9M1 each, covered sharp edges and higher voltage input (still having breakdown along resistors at 60% of maximum input, had to insulate the with plasticine).
Results: 13-14 cm sparks.
Longer resistors.......maibe they will come finally.....
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....and they came, but what desillusion...They are longer but with terminal metal caps, so they were shorted almost imediately along the surface. Desperately I used some low power 510 kohms resistors (2 in serie for 1 Mohm/ stage). The spark rate was higher and the sparks longer (the caps charge at higher voltage), but the base ones smoked in a few seconds. Here is what I used:
