Living in North Texas. I have been seeing plenty of electrical arcs lately, due to the unprecedented storms we have been having through the month of May. A few of these arcs have been destructive — one of our sound system amps at our church started billowing out acrid smoke about the same time that we had a very close lightning strike, another local church took a direct hit a few weeks ago, and just the other day my friend Roger KE5YTA lost a radio power supply due to a very close strike. Another friend, Don AE5DW in Louisiana took a direct strike two weeks ago and basically lost everything electronic in his house.
555 Timer IC (Wikimedia Commons photo)
Aside from the sights and smells that lightning and electrical arcs can create, they usually make a loud and obnoxious noise. That’s why I was impressed when I saw the DIY Plasma Speaker on Instructables today. Instructables member [tanner_tech] used a classic 555 Timer IC and a flyback transformer, high-voltage mosfet, and a fast diode from an old TV to make music. Literally, you plug in any sound source and it creates (surprisingly) high quality audio from about a one inch high voltage electrical arc. Visit the Instructable here and watch his YouTube video below — if you want to skip the technical stuff the music starts at about 3:10. Then you just might want to go back and watch the technical stuff.
Basically you are using the voltage in the battery to create a magnetic field in the section of the coil of wire that the battery is in. The magnets on either end serve two functions – they conduct the battery voltage to the coil, and they serve as the opposing magnetic force that the moving magnetic field pushes against.