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Tesla Downunder

An Australian high voltage site from Peter Terren (aka Dr Electric)  with 200 projects such as...

Current performance in Australia's Got Talent  
I was invited to perform in the auditions of Australia's Got Talent in Perth and it screened on May 10th Channel 7.

Here is a 7 second animated gif version of the 2 minute act.


Australia's Got Talent


Below is my performance from  visible on YouTube worldwide (not just limited to Australia)Dr Electric if you please...

wesome to be near
Below is the performance from my video camera (used for safety monitoring).  It includes the original sound track and lots of other stuff not seen in the televised show.

Mini Tesla coil topics on this page include:


Briefcase Eye of Sauron using an ionic spinner and a long exposure.   Briefcase Tesla coil     


   Mini coil    


   TC on a car  

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Briefcase Tesla coil 2009
This is my latest easily portable mini coil which gives 2-3 inch sparks. These are great fun and are generally safe due to low power.  The are still impressive as you can get close to them and interact with them.  This one is mains powered but setup is in seconds - open the briefcase, drop the secondary coil in place and turn on.
It was designed as a replacement for my original "mini" coil with a number of improvements, particularly in power, weight and portability.

Briefcase closed
  (click to enlarge)

It runs from a 4 kV 24 mA NST (neon sign transformer) with a double spark gap made from copper pipe. The sparks from this are green through the green tinted acrylic. The tank capacitors are 1000 pF 30 kV ceramics. These are connected as a three strings of two (hence total is 1500 pF at 60 kV) and do get warm in operation. The primary is 10 turns and secondary 300 turns on a 3 inch former. Sparks are up to 3 inches. Ground is to the metal chassis which is also connected to mains ground. There is a mains interference filter (ex microwave oven), LED indicator and switch which is simple and compact.

I eat sparks for breakfast.Safety glasses!  (click to enlarge)

Above show some stunts possible due to low power.

Briefcase Eye of Sauron using an ionic spinner and a long exposure.Light globe as plasma ball.  (click to enlarge)

Animated gif of a CD burning with the briefcase Tesla coil.
(animated - click to run)

How about CD burning, above? The spark eats away at the foil layer until it is mostly gone.  This takes up to 5 minutes.

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Mini coil 2004, 2009

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This is a small coil running on half of an NST giving 6 kV at 30 mA . The other half of the NST had been burnt out and increased the current draw mildly. The spark gap used 3 segments of an 11 segment (as used by the TCBOR and Richard Quick) gap with 1/2 inch pipe close but not touching. If made specifically for this coil then 4 or 5 copper pipes could have been bolted on to a flat section of acrylic or other insulator as the geometry of the cylindrical setup is trickier. The primary is a cylindrical 15 turns of PVC coated wire and the secondary is about 11 inches with 260 turns of 20 G (0.031 inch = 0.81 mm) enameled wire on a 4 inch PVC pipe. In the photo on the left you can see corona at the top of the pink primary winding. The spacing between primary and secondary is also from the same 4 inch PVC with two sections cut longitudinally to allow them to snap on to the secondary. This close coupling is not ideal probably gives this more 'transformer' action than 'resonant' action and to reduce power, it is run well away from resonance.. The capacitor is a series connection of 13 x 100 nF 2.5 kV ceramics giving 7.7 nF at a nominal 32 kV. There is no toroid and the secondary earth goes to the NST and mains earth. This is about as quick, easy and safe as they come for 2 inch sparks.

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Above, for kids of all ages.  I probably run this coil more for demos than any other as it is quick, easy and safe.

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Above, for 2009, I have changed the caps again. The originals are shown on the left (one string of 13 x 10 nF @ 2.5 kV = 0.77 nF 32 kV) which lasted 20 years and have a couple of failures.  The center caps were the disastrous ones which fail after only minutes (Five strings of 10 x 10 nF @ 3 kV = 5 nF 30 kV).  The new ones are on the right (2 strings of 2 x 1 nF @ 30 kV = 1 nF 60 kV) seem to work so far. I have also removed windings back to 10 turns on the primary to improve spark length to 2.5 inches (6 cm). Also changed the setup to have the spark gap across the transformer secondary which gives it better protection. I have added some mains filtering and an aluminum sheet centerpoise at the base.

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Two inch sparks onto my hand. There is some motion artifact with my hand but not the equipment or sparks. This is done with a clear knowledge of earth paths and at very low power levels on a small coil with no toroid capacitance. Wetting my hand beforehand reduces the sensation to a repeated pinprick sensation.

This coil has been popular way beyond the effort to make it. It has now been on Australian TV on 3 occasions and overseas on 6 (China, Holland, Norway, Switzerland, Denmark, Turkey and likely others as well).   Now on loan to the Physics Dept.

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Tesla on a car 2005
For a bit of silliness, I put the mini Tesla coil above on my car.

My Honda Civic at the time was 20 years old (which makes it younger than the Space Shuttle). To run my stereo I have had a 300 W inverter in there for about 15 years running a 100 W/ch hifi amp and 8 ohm speakers which used to take up all the parcel space and back seat as well. The inverter has been utterly reliable and in the meantime I am on to my third amplifier and third set of speakers.

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I simply plugged the Tesla coil in to the 300 W and put it on the roof. It is perfectly capable of being driven around but is rather underwhelming for that. As a precaution I earthed the car aerial but I probably didn't need to as I have run a car radio only a foot or two away from 4 foot sparks. I suspect they have very good static suppression.  The Honda died later that year (unrelated to the TC) and as a mark of respect and mourning I have not bought a replacement but use my bicycle instead.  I continue to do so in 2011.

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Of course, since 2005 I have done a lot of TC on a car stuff which is vastly more spectacular. If you don't see anything else on my site, see this.

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