Ikle Tess was built because of a comment at the 2003 Derby Teslathon , “when I was little I used to try to get as higher voltage as possible from a 12v battery”. This rang a few bells with me, and I thought I would have a go.
Not being able to find my first choice of transformer, a monitor or TV Line Output Transformer . I had to settle for the more readily available Car Ignition coils. I built a simple NE555 & 2N3055 circuit to power them and used a string of three 18Kv diodes to rectify the output. The rectified output from the coil charges two 2.2nF 25Kv capacitors in parallel.The capacitors are discharged through the secondary by a small rotory spark gap. Later a second driver circuit and ignition coil was added to give twice the charge rate.
The primary is 8 turns of 2.5mm insulated multi-strand wire, super glued to an acrylic frame.
The secondary is 600 Turns of 0.25mm enamelled wire wound onto a cardboard kitchen towel roll 1.3” in diameter and thoroughly varnished.
An air freshener covered with aluminium tape makes an ideal top load.
The addition of a small (55mm diameter) rotory spark gap , (See picture) this has increased the power throughput, but with no increase in spark length..
Spark output is around 4-5” arcs very thin and wispy, nice corona around the top load , but its so dim as to be almost impossible to capture with my camera.
The best thing about the coil is that it is safe(ish, there are NO totally safe voltages or currents) the only possibility of a large shock is if you took a full charge from the primary cap.
The rough circuit of the ignition coil driver can be found here http://www.geocities.com/CapeCanaveral/Lab/5322/coildrv.htm
|New Rotory spark gap. Double strength sparks..
|The coil in action. The scary thing is the red glow on the LHS is the end of my finger!!
|Better pictures taken at the Cambridge Teslathon