3 Inch Tesla Coil, 6-8" Arc

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.