Tesla Coil #2

My first results in building a Tesla Coil were encouraging, but running the whole system on a battery pack with a 555 driven flyback transformer was not the best I could get. Still those of you interested in seeing my first steps in the Tesla Coils realm can have a look here My second attempt and the subject of this article, came with a change in the power source. As advised by Teslina I tried to use a ZVS driven flyback with builtin rectifier to power the tesla coil.

So I’ve built a new ZVS driver soldering the components above a heatsink. I’ve used 2xIRFP460 mosfets, 2xBYV26E as fast diodes, 2 15V Zenners and a 50coil iron-core inductor.

For the flyback, first I’ve tried a twin setup, by using two monitor flybacks, both with built-in rectifiers.
The primary must be shared, and the two secondaries connected in series for summed voltage output:

Luckily I’ve found a better flyback that did the job of the two, so I dropped the design above. Still it’s useful when you want to get a bit more voltage and you only have small monitor flybacks.

I’ve used the half wave rectified output to charge a bank of capacitors, summing 6nF 18KV. Here’s the simple Tesla Coil schematics for rectified current:

And here are a few pics and vids showing the Tesla Coil in action:

Radu Motisan

My first TEA Nitrogen laser

Well known for high voltage enthusiasts is the nitrogen laser, that uses a high voltage source and the nitrogen in the air. What’s more difficult about it, is to arrange two electrodes to be perfectly parallel for an homogeneous discharge between then. Luckily while building my own, I came up with an idea that most of you will find useful.

First I need to say that I won’t be using aluminum foils, but real capacitors.
So let’s assume the electrodes are 2 ruler shaped metal pieces.
You can drill 4 holes, that would form an imaginary rectangle, two holes in each of the metal plates.
Using a non-conductive material, you can create two bridges between the two electrodes. This way you will have a rectangle shape, were the electrodes are parallel:

The good thing is that you can always loose the screws, so the rectangle shape can be easily shifted to the right, to a parallelogram shape.
This way the electrodes will always stay parallel, but the distance between then can be adjusted.
You will need to put some metallic spacers between the wooden bridges and the electrodes or else you’ll have arcs in that spot, that will burn the wood. It happened to me (see the marks left of the wooden bridges).
So one electrode can be free to shift left/right, and the other can be fixed to a holding plate.
Here’s my setup:

For the power supply I’ve used my ZVS driven flyback with built-in half wave rectifier, and a few hv ceramic capacitors (2x 18KV 3nF). Some designs use homemade plate shaped capacitors made of aluminum foil, but I don’t recommend it.

Here’s the laser firing, but apparently not working correctly:

The spark gap makes a lot of noise, and very bright discharges, so it’s very important to wear safety UV glasses.
A few videos:

For those of you willing to try this, you might need this as well:

Hope you enjoyed this,
Radu Motisan