As the founding father of alternating current, the legacy of Serbian-American inventor Nikola Tesla is felt every time we use an electrical device. But, of all his creations, only the Tesla coil bears his name. For aesthetic appeal, historic legacy and a satisfyingly high level of danger, the Tesla coil is the ultimate fringe science icon, a role it has played to perfection in the laboratories of numerous Hollywood mad-scientists.
The device is a step-up converter that uses two resonant coils to transform low voltage input into extremely high frequency, high voltage output. Usually channelled out via a toroid cap, the spectacular and intense discharge is essentially man-made lightning.
Tesla unveiled his first coils in 1891, to demonstrate his dream of wireless power transmission, which he would do successfully using a 60m tall, 15m wide coil at his Colorado Springs, Colorado, laboratory. This coil, which easily generated millions of volts, reportedly produced great sparks 40m long and could transmit electricity, wirelessly, over 50km.
It's said that the surrounding prairie shook as thunder and lightning erupted from the lab, while locals described sparks crackling underfoot some distance away. Tesla hoped ultimately to transmit power worldwide, despite his fear of igniting the Earth's atmosphere through his experiments.
Following a number of failed business ventures, Tesla faded from view and died an anonymous death in 1943. But a version of his coil technology would be used for decades in radios, cathode-ray tube televisions, and in diathermic medical equipment.
In the 1970s artist and engineer Robert Golka built a 37m tall Tesla coil in a hanger at Wendover Air Force Base in Utah. Golka, who declared his own coil to be more powerful than the one at Colorado Springs, initially attempted to create ball lightning with the tower, allegedly with some success.
His coil was later commissioned by the US Air Force to test the effects of lightning strikes on aircraft, leading to rumors of a lightning weapon.
Today Tesla's vision is kept alive by a global network of enthusiasts, known as coilers, who stage often spectacular public demonstrations, inspiring future generations of lightning junkies.