I'm trying to build a Tesla coil, for the first time, and have some questions. Whatever sources i came across on the internet only tells how to build one out of household items, trash, radio shack components, etc, but not why and which way the thing works. The thing: http://orbides.1gb.ru/img/img_0413.jpg The sparking coil is a A3 sheet of paper rolled to 7cm in diameter, with wiring on the first 18 cm of it, roughly 250 loops. http://orbides.1gb.ru/img/img_0417.jpg The main coil is on the bottom, 14 loops of the slightly bigger diameter as the spark one. http://orbides.1gb.ru/img/img_0416.jpg 20KV 680pf capacitor in the circuit. http://orbides.1gb.ru/img/img_0415.jpg Roughly 0.6cm spark gap parallel to the circuit. http://orbides.1gb.ru/img/img_0418.jpg And a pocket taser as a power source, which stops sparking at about 2cm distance between terminals. Now, the questions are: 1. The spark coil produce only at most 1-1.5cm streamer between lower and upper wires, which is less than what i expected. Is that normal, or should it be better on such a setup? What determines the spark length - power, tuning, frequencies, geometry, proportion between all of the said things? Is anything obviously wrong in the design? 2. What the spark gap distance responsible for? Does it only control the frequency, or something else? 3. On the sparking coil, the wiring insulation seems perfectly conductive for the voltage being generated in it, if the lower wire is brought near the wiring, sparks form. Is that normal, or should the wires be better insulated? 4. The capacitor is rated for 20Kv, while the taser gives up to 2cm arc, which i translate into 60Kv. Now, the spark gap being set to less than 0.5 cm should limit the voltage going into the capacitor well below 20Kv, right? If not, what will, and what is the impact on the capacitor? It's not easy to get a new one if that one will burn. 5. How dangerous a charged 20Kv 680pf capacitor is? Are we talking about shocking, lethal, or explosive? And, how do i calculate that for a different capacitor? 6. What could be used for grounding the lower wire of the sparking coil? Central heating radiator doesn't seems right, and the earth is far below and well paved.