The second post on my tesla coil project and I'm already over budget. This doesn't bode well. My goal was to stay under $300 for the initial project, but purchasing things online adds up, especially with shipping costs and minimum purchase limits. Right now I'm at $320 dollars. Luckily, the only major componet I have yet to purchase is a couple thousand feet of magnet wire.
Next step will be to work on construction of the NST protection filter. I'm using a design by Terry Fritz. A filter is needed to protect the transformer from high voltage surges created in the primary that can make their way back to the the relatively delicate windings of the neon sign transformer. This filter protects the transformer in a couple of ways. It 'removes' the transformer from the primary coil circuit via the 1K Ohm resistors, the safety spark gaps ground high voltage spikes by allowing them to easily arc to ground, the varistors shunt high voltage to ground, and the capacitors also help absorb (and bleed off via the resistors) voltage spikes.