I'm trying to figure out what are the paramters that cause a spark.... a visible spark. For example, if I take a 9V battery and connect the leads together with a small wire, no spark... I imagine if I get a 12V battery and do the same thing, no spark (I'm refering to therelatively small 12V batteries that duracell and energizer make,) now take a car battery and no doubt you get a spark... but the voltage is still pretty low 9-13V... low voltage stuff, wikipedia says
"A spark is triggered when the electric field strength exceeds approximately 4 - 30kV/cm[2] =97 the dielectric field strength of air."
I can't tell if they mean 4V - 30kV or 4kV - 30kV, if they mean the latter... then batteries are no where near that
so... the difference between the car battery and the table top battery is how much current the thing can source, right? so is that the parameter... can a 2V battery that can source 10A then cause a spark (if you short the leads) while a 10V battery that can source 100mA can't
I'm only talking about visible sparks, and I'm not talkin about static electricity, just shorts... no esd
any thoughts? thanks