Inspirations on construction of the 12kv/60ma Table Top Tesla Coil




In the early 1990’s, I was showing some friends of mine in the radio shop some photos of  “pre-Zotzilla”; a medium sized spark gap Tesla Coil. I had taken pictures of the sparking in the driveway and was quite proud of the 5 foot-plus arcs I was getting. There were spark gap and heating issues I was dealing with. One of my radio tech buddies; Dan May, told me about Harry Goldman’s quarterly publication of the TCBA (Tesla Coil Builder’s Association) Newsletter. He brought in a copy for me to check out. Of course I immediately subscribed to the newsletter. I found Harry to be a very nice gentleman to talk to. After some correspondence with Harry regarding a new rotating spark gap I was working on, I had received a small list of coiler’s in the Phoenix area with my newsletter.


One of the names on the list was Jeff Mullins. Katie bar the door! Once Jeff and I started ‘Talking Tesla’, we would go on for hours with ever more inspiring conversations! Jeff, through the help and mentoring of Thorn Mayes had designed and built an extremely efficient neon sign powered Table Top Tesla Coil. Jeff came over to my house on a cool evening in the spring of 1993 with a working model of this coil.


I had never seen anything quite like this before. Everything from the 5-break spark gap, beautifully made primary winding, homemade energy discharge capacitor took a back seat to the performance: The primary was a mere 12” or so tall and would through throw sparks nearly twice it’s own length!…awesome! I ask Jeff if it would be OK to call my friend J.O.; as he wouldn’t believe his eyes either…”you have to see this to believe it!” Within short order, J.O. was there. Obviously being quite excited, he exclaimed: “we have to build one of those!”


With Jeff’s mentoring, J.O. and I proceeded on an unstoppable mission of building our own Table Top Coil that was not only beautiful, but had stunning performance as well and would be a hit for school demonstrations and get-togethers for years to come!


During construction, we were faced with only one problem: The un-availability of parts. There just aren’t many Tesla Coil Stores in our neighborhood. What ever we needed we had to make. So make we did.



Here are some specifications of the Table Top Tesla Coil


The box the Tesla Coil is mounted on was originally a calibrator from the 1950’s used by the US Navy Department of Ordnance. I had purchased it from Crash Leyland, a movie writer and musician friend in Crown King, Arizona under the following conditions: If I modified the box, I must retain the “Bureau of Ordnance” placard on the front, as original.


Secondary:       11 1/2 inches of #31awg

Top Load:        Two ten-inch frying pans, welded and polished

Primary:            About 18” diameter spaced every ½ inch

Condenser:       Energy Discharge TCBOR design, oil filled, home rolled in J.O.’s shop by Jeff Mullins

Transformer:     12kv/60ma Fransformer

Spark Gap:       Jeff Mullins design, 5-break, ½ inch tungsten rods held in place with line-bored 308 stainless steel posts custom machined by Terminator Tommy



Performance:    18 to 22 inch sparks (depending on the weather)

                        Over 700 hours of operation with no failures to date!

Coil was operated for hours at a time at the 1998 IBEW trade show in Phoenix, AZ

Coil was featured on TV Channel 3’s show “Brainstorm” for a special on electricity.





I wish to thank all that have participated in fulfilling our dream of building this nostalgic-looking high quality coil. It took a lot of hard work and cooperation but the results were well worth the effort! Most important was the inspiration of Harry Goldman and his hard work publishing the TCBA Newsletter and bringing fellow coilers together.




Henry Hurrass