My first Tesla coil using a neon sign transformer with a ferrite cored secondary giving 2 inch sparks.  I developed this idea with an old transformer from a dumpster which in retrospect was an old unpotted NST (neon sign transformer). I used a single static gap with a 12 inch ferrite cored coil of 11 primary and 100 turns secondary giving 2 inch sparks with 26 small ceramic capacitors with 2 strings of 13 x 10 nF at 2.5 kV each. It ran nicely for about 20 years!  This photo is a mock up with most of the original parts.

I developed this from my first “Tesla coil” discovery while doing a spark spectroscopy project.  Years after I made it I heard that Tesla had beaten me to that discovery by quite a few years! This photo is a mock up with most of the original parts.

It now has new life as a Jacob’s ladder.

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Photo Date: Jan 19, 2003