Tesla Coil!

This is my first blog post ever. But might as well jump right in.

The current project I am working on is, contrary to what the title of this blog may insinuate, a Spark Gap Tesla Coil. Tesla Coils are famous for their awesome ability to produce beautiful arcs of plasma that resemble bolts of lightning. Because of this effect, Tesla Coils are often described by laymen as "lightning machines."

The Tesla Coil is essentially an air core resonant high voltage transformer, wherein two loosely coupled LC circuits cause a massive voltage to build up on the secondary circuit's capacitor due to an effect known as resonance. The first LC circuit, the primary circuit, is connected to a high voltage transformer and has a spark gap running in parallel with the primary coil. The high voltage transformer charges the primary (tank)capacitor, whose voltage builds up high enough to ionize the air in the spark gap. This effectively forms a LC circuit. The energy stored in the LC circuit oscillates between the inductor and capacitor at its resonant frequency. Because of the loose coupling between the two circuits, some of the energy is transferred to the secondary each oscillation, and because the two have the same resonant frequency, this effect happens every single cycle, building up the secondary voltage until the electric field on the secondary's capacitor is too great, and an sparks start flying.

The coil that I am currently working on was initially completed before before this blog.

This coil ran on a Neon Sign Transformer with a output voltage rating of 7500 V and a current rating of 30mA. The tank capacitor is a MMC created with 10 Cornell Dubiliers each rated for .15 microfarads and 2000 volts. The resonant frequency of the LC Circuits are 265 KHz. The primary coil is 15 winds of 14 gauge wire of a helical coil.

Unfortunately, there were some serious design oversights in the first construction of this coil. The first, and most egregious of these was that I accidentally grounded my secondary coil through the windings of the primary. The second problem is that thee helical coil overcoupled the two LC circuts. The secondary coil was also badly insulated. These problems led to both primary-secondary arcing, and racing sparks.

Because of these problems, I am currently in the process of redesigning and recreating the coil.

Updates soon!