How do I measure very very high voltages? there are from a car ignition coil? no expensive answers no 1000x scope probes, but I have a x10 probe lol. I need to measure the output from a ignition coil with 18V going through it on the nice side, what I want to measure is the output. I need around 31,000V lowish Current (around 200mA) its for growing a crystal, well for kind of altering the shape as it grows.