Quote Originally Posted by NickThissen
A few friends of mine built one at college last year... Their goal was to make it 'play music' (theres a video going round on youtube I think about one making christmass music or something). It works by making the sparks jump over at the right frequency or something which creates some kind of weird buzzing sound...

But they had to stop when they blew out all the lights and a computer in the classroom hehe...
Yeah that's a solid state coil, harder and more expensive to build than a spark gap one. Would be cool to have one though.