What is it?
So, I'm sure you've all seen a jacobs ladder before. If not in person, then in your favorite mad science laboratory. Yes, it is that thing in the background with the arc of electricity going up the two wires.
How does it work?
A Jacobs Ladder is a very simple device. Essentially, you have a source high voltage and reasonable current, and 2 wires. When the voltage between the two wires becomes great enough, the air between them breaks down into plasma. The less air between the electrodes, the less voltage required to break it down, which is why the electrodes are "V" shaped.
Plasma is 2 things; conductive, and very hot. Because it is hot, it rises, which is why the arc rises between the electrodes. Because it is conductive, that aforementioned reasonable current (>30mA) flows through it. The more current you have, the higher the arc can go; because more plasma is made, so the plasma can be streched further (in adittion to being brigher and louder, which is always better).
How to build a Jacobs Ladder?
As stated before, all you need is a power source, and wire. I've found that aluminum wire works best because it is light enough to support itself and stiff enough to stay nice and straight. The power supply warrants a bit more discussion.
There are quite a few viable supplys for a jacobs ladder, the most common are-
- Neon Sign Transformer
- Micro-Wave Oven Transformer
- Flyback Transformer
- X-Ray Transformer
By far the most common, it has a high enough voltage to self ignite (12-15KV) and enough current to be cool (30-60mA) and will set you back about $40-$60.
Dirt cheap if you know where to look and are paitent, with a LOT of current capability (1A), but unfortunatley they have a relativley low voltage and the arc needs to be ignited manually
Also cheaper than your average dirt, but they require some external circuitry because they operate an a high frequency. They are also kinda lame for this since they lack the loud 60Hz sound of the other transformers.
By far the coolest. And most dangerous. These will set you back about $100, and run at about 140KV, which means it will gladly jump a foot through the air to bite you. If you own one of these you probably already know what you're doing.