Trust Britannica to give you all the Modern Materialistic palp.
Yes, i have learned all that shit through years/decades of college.

The phone company runs on 42 volts. They have a giant battery bank.
With a copper bar on one wall for positive, and a copper bar on the other wall for negative, so you cannot touch both at the same time.
One technician had his face melted off because his wire rim glasses fell off his face.

It isn't really volts or amps, it is power potential.

A Tesla coil is a very high voltage, very high frequency transformer.
If all is done correctly, it doesn't hurt at all. It goes around the body.

The problem comes in when you don't get everything in balance, and you get some low frequency stuff going through. And still, it is not usually bad, just irritating. Get good plans and do your best to follow them.