What am I missing here? I know USBs don't kill you so I know I've got something wrong. Google tells me that around 0.1A has a really good chance of killing you; and everything I read says it's the amps that kill you not the volts. So I know van der grafs and static shocks won't kill you. My USB charger puts out 5v DC at 2.1A. But it aint going to kill me. Things I think I know (dangerous - I know) 1. So I can see the volts are much lower, but if 50,000 volts won't kill you from a van der graf then I don't think the difference between 5v and 110v is the key 2. I'm missing resistance. I don't really know what "5V at 2.1A" means. I though I did, but if V = IR and I put the positive and negative ends of the USB together so resistance was close to zero; 5 = 2 x 0 ??? I got that wrong somewhere! 3. Google tells me that the body has a resistance of anywhere between 100,000 ohms and 100 ohms (if you are wet). It also tells me "For currents above 10 milliamps, muscular contractions are so strong that the victim cannot let go of the wire that is shocking him. At values as low as 20 milliamps, breathing becomes labored, finally ceasing completely even at values below 75 milliamps" So if I stick that in the V=IR equation, Amps = 5/100 = 0.05; which suggests my USB could kill me. What am I missing?