I'm going to underscore what Darrel has already stated--always treat electricity with respect!

My knowledge of history isn't all that great, either, but I believe the AC versus DC issue began with Edison versus Nikola Tesla; Westinghouse came in a little later.

On one hand, I routinely test 9-volt batteries by touching the terminals to the end of my tongue. In high school, I knew a TV repairman who could tell whether the AC line voltage was right by touching two bare wires with one hand, and he died of cancer at age 81. And a former co-worker of mine, about four years ago, survived 28,000 volts DC (television transmitter) but had some nasty burns and many skin grafts after. He's also suffered some subsequent neurological problems. (If you think I mean, "He's not as sharp as he used to be," you're right.)

When I was a kid, I learned the "one hand in your pocket" rule, and I still use it. (When you're working with a live circuit, keep one hand in your pocket.) All my close encounters with electricity have been with one hand--including about 1000 watts of RF across the palm of my right hand (and a burn). The scariest shock I ever got was from 90 volts of AC telephone ringer--again, just my right hand, but it wanted to grab and hold on.

And, of course, whenever possible, work on the circuit or equipment with the power off!

My understanding has always been that current kills, not voltage--otherwise we'd all keel over and croak when we get that static shock from a doorknob on a really dry day. The big difference, supposedly, is that low-frequency AC disrupts the electrical rhythm of the human heart, so it is much more dangerous at comparatively lower voltages; high-voltage DC just cooks you.

Don't be a resistor! (Very bad pun . . . )