Re: zapper

You'd may kill or hurt the person if too high, but you are basically right. More volts may be useful. Clark also stated the limits on zapping.
"The current travels along the stomach or intestinal wall, not through its content. It does not reach into the Gallstones or into the living cells. The current does not pass uniformly through the body. With regular zapping, the current passes mainly through our liquids, i. e our lymphatic and vascular system, a small fraction reaches every organ and tissue of our body."
It helps if you zap a lot but it won't get to every area of the body. A plasma device might, but quality and stability varies a lot on those. Some pad type units use carrier waves combined with the basic wave to carry the signal deeper in the body.
Some stuff can be pretty complicated but then that can also mean it is not simple, cheap or portable or even battery operated.
It's like weapons. Different things have different uses.