Before revision: Their construction usually featured a disruptive discharge coil with an interrupter to apply a high voltage, high frequency, low current to the human body for therapeutic purposes.. Overview Their basic construction was invented before 1900 by Nikola Tesla , who introduced his first prototypes at the World's Columbian Exposition in 1893.
After revision: Their construction usually featured a disruptive discharge coil with an interrupter to apply a high voltage, high frequency, low current to the human body for therapeutic purposes.. Overview Nikola Tesla introduced his first prototype violet ray at the World's Columbian Exposition in 1893.