Tesla transformer, many used as a decorative item.
Transformer Tesla (Tesla Coil) - A device invented by Nikola Tesla and bears his name. Is a resonant transformer that generates a high voltage high frequency. The device was patented September 22, 1896 as "a machine for the production of electric currents of high frequency and potential." The voltage in the frequency of the minimum electric strength of air is capable of creating impressive electrical discharges that may have a length of several meters. These phenomena are charming people, so many of Tesla transformer is used as a decorative item.