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So I know that you need a certain current flowing through you to die, I've heard from some people "its the amps that kills you", and from others "Its the volts that drive the amps" and I realize that these are true according to ohms law v=ir or i=v/r.

But I was watching this video: https://www.youtube.com/watch?v=ubZuSZYVBng

A guy touches a constant 200kv and i've seen a similar experiment in real life, assuming that his body has 100Kohm of resistance which is generous, thats 2 amps flowing through his body if you use ohms law, and realistically way more as there would be less resistance and it would decrease after it makes a circuit. How is this possible without him dying?

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  • \$\begingroup\$ A Van de Graff generator generates static electricity, which is quite different from AC or DC. \$\endgroup\$ – DerStrom8 Jan 29 '16 at 14:46
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A Van de Graff generator can only deliver microamperes of current continuously, so the voltage was no longer 200kV or whatever after he touched it. It was probably less than 1 volt.

If you want to look at it more technically, the generator is like a constant current source of something like 10-50uA (wild guess) feeding into a capacitor and some leakage to ground (corona discharge) that occurs at high voltage. Discharging the capacitor of (the hemisphere at the top has some capacitance) and you're left with just the microamps of current, which is not remotely enough to be dangerous.

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ This source states around 0.5J of energy max stored on the domes of a school-grade VDG. That equates to about 25pF @ 200kV. 1J is required be rather dangerous according to that. \$\endgroup\$ – Tom Carpenter Jan 29 '16 at 3:59
  • \$\begingroup\$ So ohms law is still applied, the voltage just lowers, Thanks for your answer! \$\endgroup\$ – Rhezner Jan 29 '16 at 4:02
  • \$\begingroup\$ @TomCarpenter According to what this source says about IEC61010-1 0.35J is considered safe, so I guess they're on the edge of what is 100% guaranteed always safe for all humans regardless of health. Thanks for the reference, I reduced the capacitor in my 'typical model' which was based on a 14" (350mm sphere \$\endgroup\$ – Spehro Pefhany Jan 29 '16 at 4:20

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