it just uses high voltage through the adjacent wires... if i remem well, inductors are used for generating them using inductive kickback that is why it isnt that harmful to us....
k... this is the basic idea that i was talkin about.... we use a square wave generator which at its output has a diode and inductor connected in series.... when the output of the square wave generator goes low the inductor shows kickback and the diode protects the square wave generator by going to reverse bias... the square wave and the inductor determine the working voltage....