The Tesla coil is an electric transformer-like device, which, by using the sector’s 220V, allows raising the voltage up to several hundreds of thousand volts, and sometimes up to several millions for the biggest devices. This is perfectly safe because the intensity of the current at the end is incredibly low. This device allows to get spectacular effects at a low power : our coil, in full work, uses only about 600W, which is far less than a hair-dryer, for instance.
The first Tesla coil was created by Nicolas Tesla (Croatian – 1856-1943) for Chicago’s World Fair in 1893. He submitted a design that generated spectacular electrical sparks that were about 10 meters long and that allowed transmitting electrical current wirelessly.
Tesla went further on his works on electrical resonance (the phenomenon that allows the coil to be operated) in Nevada. There he built a 60m high coil in the hope of making our planet resonate electrically. Unfortunately, our planet’s reaction was disturbing the neighbours and he had to give up his projects after a last experiment in which, after he had literally used all the electrical power of the neighbourhood, a 40m long spark fell on the ground, wiped out a field and created a deflagration that could be heard up to dozens of kilometres round.
Many years later, Tesla would find himself told to be the inventor of radio instead of Edison. Indeed, the coil’s electromagnetic field could be picked up on the other side of the Atlantic, thus allowing the transmission of information.
Nowadays, it seems that the Tesla coil has been completely forgotten. And yet, it still has many fans, especially in the United States, where they build and set up designs of this wonderful device during their leisure.
For the video-games lovers, the famous “Command and Conquer – Red Alert 2” allowed it to be brought out of oblivion with the Tesla Soldier and the Tesla Tower (these two units are actually far away from the reality … )
A quite common object inspired from this device is the “plasma ball”.
Finally, there are companies that build huge coils designed to be used in the movies industry, in order to create special effects. They can also be used in laboratories in order to test insulating material.
In a less funny way, the big electromagnetic field created around the coil during the use can disrupt, or even destroy the electrical devices. This is what gave the Defence the idea of the electromagnetic bombs that could destroy any communication means and any computerized defence system.