This is one of the simplest complete coils we've ever constructed. It's very cute, and performs well for utilizing a "single static" type spark gap. Here are some quick spec's: Input Power: 9kV 30mA Neon Sign Transformer 9000 * .03 = 270VA Secondary Winding Impedance @ 60Hz - 300kohms Secondary Coil: Winding is 3.5" O.D. x 10" on 11" PVC pipe section Wound with 460 turns of #24 from www.mouser.com Coil resonates at approximately 900kHz (with very small topload) Sealed with a THICK (1/8"!!) layer of "Minwax" brand polyurethane Primary Coil: 5 turns of .25" copper tubing, .25" spacing between turns 1" clearance between primary and secondary coils Winding is tie-wrapped to a square acrylic baseplate. A simple, but effective technique Spark Gap: 1/2" O.D. x 2" long stainless steel electrodes Electrodes are permanantly mounted onto small acrylic baseplate .2" max gap spacing No cooling/quenching fan is used, but does well because of large electrodes to sink heat Tank Capacitor: MMC Design Capacitance: .004uF Voltage Rating: 15kVDC Off-Axis Inductor: 20 turns of #14 bare copper wire, wound onto 3/4" PVC pipe. This inductor makes tuning a breeze if you want to use a larger topload. Tapping it is also much easier than tapping a primary coil, for obvious reasons. We have used off-axis inductance successfully on several other, higher-powered coils.Go Back to the Main Site