This close-up time exposure shows Van De Graaff sparks jumping to the demonstrator's hand like miniature lightning bolts! The 400,000-volt spark from the tabletop Van De Graaff machine can give a good jolt when it jumps to a person's skin - but it is otherwise harmless, as seen in this photo. Unlike the dangerous Tesla coil, tabletop Van De Graaff generators are safe to handle and touch.