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I have always had an interest in high voltage. I could spend hours watching lightning, marvelling at the energy and beauty of the deadly play of light. Being bought up in the Far North of New Zealand you could almost guarantee a couple of good lightning storms a year.

Anyway, a friend lent be a book about Nikola Tesla, the man we pretty much owe our "modern age" to. Very few people today who work with electricity know who he was. He invented (among many other things) AC voltage, polyphase motors/generators, high frequency resonant transformers (tesla coil), carbon arc lights, radio, logic gates and wireless transmission of energy - to name a few.

Anywhoo, the tesla coil is a fun device, relatively easy to build, can be built on a (very) small budget if you're resourceful, and could kill you before you know it. Complacence or lack of basic understanding is suicide with these coils.

Essentially the design is very simple, you need a stepup transformer (neon sign transformer - NST), Capacitor tank (beer bottles filled with salt water sitting in salt water), a spark gap, heavy cable primary coil (7-10 turns), and thin wire wound round a length of pvc (600-1000 turns).

This was my first coil, I was shocked (not literally) that it worked, but it did.

Maximum spark length was about 2½ inches. It kept me entertained for hours.

The PVC pipe was about 1.25cm diameter, 3 feet long, and the winding wire was salvaged from an old 24volt relay. Powered by a 12kv 30ma neon sign transformer, salt water tank cap with 4 -330 ml bottles filled with saline water sitting in a bucket of saline. Spark gap was a pair of carbon eletrodes salvaged from a 6 volt battery and no quenching was used.

The bottom picture is a closeup of the coil in action. The bulb above the coil on the left is a car headlight with the contacts going to earth (note the streamers inside the bulb). The second is a low current neon bulb. My guess output is about 20-30kV from the coil, perfect for mucking up the neighbours annoying HAM radio. Haa Haa, revenge for his interference. I havent noticed him using it for a while, perhaps his aerial was in tune with the coil (oops :)

(Click images for larger picture)


>>> On to my New Coil, "Baby".


Ps, if you kill yourself reproducing anything you see on this site... it's you own bloody fault and don't come screaming to me.


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