Simple plasma globe

Introduction

When I first started experimenting with high voltage, flyback drivers were among the first supplies I built. I did a lot of weird experiments, but never got around to make a plasma globe since I wanted to do it with a big clear bulb.

Now I bought a big bulb, I have some better flyback drivers… 1 + 1 … it is time!

Warning: Touching the globe can give some nasty shocks as the current is much higher in a home made globe, I only tried at very low input voltage and it was easily felt as sparks to the finger.

Safety

WARNING!: Working with electricity is dangerous, all information found on my site is for educational purpose and I accept no responsibility for others actions using the information found on this site.

Read this document about safety! http://www.pupman.com/safety.htm

The experiment

1st September 2009

I bought a 125 mm diameter Paulmann globe, the biggest the store I popped into had around.

There is a few conditions that have to be met to get discharges inside the bulb.

• An AC high voltage supply, old flybacks without rectifiers are perfect.
• One lead is connected to both terminals of the bulb
• Second lead is grounded to earth.

Then its all about getting a high enough voltage for the discharges desired.

I noticed that the gas surrounding the actual streamers was glowing green, at first I thought it was overexposure to the eyes optic nerve, but when I got a photograph of it, it got me wondering. Normal light bulbs are mostly filled with Argon and some nitrogen / krypton, but none of these gasses, pure, will emit green. So for now it must be the mix of gasses in the bulb that results in a green glow around the streamers.

Beautiful green glow can be a sign of x-rays, but the supply voltage here is below the limit for x-ray generation. If the supply voltages gets above 50-60 kV the risk of x-rays being generated is present.

Conclusion

This is an easy and fun experiment to do, if you already have a high voltage AC power supply at hand.

Demonstration