The spark gap tesla coil is nothing more than a spectacular looking transformer. Let's face it; a tesla coil has no great purpose other than to show off. The inventor of the Tesla coil Nikola Tesla, wanted to transmit energy through the air. The efficiency of his invention was anything but lousy. Classic demonstrations of a Tesla coil always produce very long visible discharges through the air of high-frequency alternating electric voltages. With the construction of my Tesla coil I wanted to use the electromagnetic field to illuminate fluorescent tubes. In the video below you can see an illuminating flourecent tube becuase of the strong electromagnetic field of the coil.