Does anybody understand the fundamentals of what is happening in this circuit? Tungsten welding info is all about high current..... but this is a low current scenario. AC input, CDI Coil generated 20Kv (estimated) suffers voltage drop over 100mm of tungsten rod. The larger the diameter...... the less voltage drop....... Yet.... I believe a pointed electrode will produce a better spark....... but by creating a point, the resistance is increasing, as the diameter gets smaller, to effectively 0.0mm diameter. Is there an event horizon, where the spark is going to jump, regardless of diameter? What is exactly happening, as the spark jumps? But more than that...... how can we get a grip of the fundamentals at play here? For example: I don't even know what the coil output voltage is, as a multimeter cannot test HT output. Searching on the web....... people throw figures around, but nobody seems to actually 'know' what is happening. Official figures don't seem to be quoted, presumably because the public cannot test HT output. Further..... if a 5k resistor is used in the plug cap....... this dramatically alters the equation results of Ohms law I'm clearly floundering. I don't know the HT voltage I don't know the current I don't know by what degree a shallow taper impedes voltage transmission. (welders go for a very shallow taper..... but they use high currents...... maybe that changes things) Does anybody understand the fundamentals of what is happening in this circuit? And, or, how to measure the HT output?