| Plasma Tubes A solid-state approach |
| Here I will give a brief explanation on how the whole thing works, how to build a plasma chamber and drive circuit. This is a relatively safe high-voltage apparatus. However as with all high-voltage extreme caution must be taken and the use of a vacuum pump can be extremely hazardous and the risk of implosion is very real at even a moderate vacuum. And believe me the weight of the atmosphere collapsing a chamber is every bit as powerful and loud as an explosion! And as always the following is for information purposes only and you should not attempt to build or reproduce any of the devices or procedures shown below. |
| So how does this thing work: In a nutshell what we're doing is removing as much of the air as possible from an enclosed chamber, in my case a Glass five gallon water cooler bottle, this reduces the number of atoms in the container creating a larger average distance between any two adjacent atoms. Next replace the air you've removed with one of the Nobel gases, you can simply leave the chamber as a rarefied air chamber i.e. you have pulled as much air as you can but you can't get it all out so there's little left this will calls the plasma discharge to be dim, Argon is the brightest of the gases next to Neon it produces a bright white spark, while the neon produces a red color. Helium is the cheapest of the gases to acquire as you can get a small tank from a party store for around $30 or if you want to be really frugal have them feel up some large balloons for you. This is not however the best method transporting gases as some diffusion will occur through the balloons membrane. Argon is probably the best choice for the beginner as is the cheapest, it produces a bright discharge, and it is readily available. Feel free to explore various pressures of gases you will be able to notice a wide range of visual phenomenonby simply by modifying the pressure inside the container.space Now that we have created a contained rarefied environment with a greater average distance between any two atoms. We are ready to excite the remaining atoms. This is done by applying high voltage rapidly oscillating electricity to both polls of the container, we will do this with two-car ignition coils and a small electrical drive circuit which will be explained later. When a, let's say helium atom near the top of the container is hit with an electron flying from one of the polls the electrons in the helium atom become excited and shift energy states. This resulted in a small packet of excess energy called a photon that we perceive as visible light also the remaining electron is sent off on a collision course for the next available Atom below it in the electromagnetic field. Where the process is repeated. Oh the reason the greater average distance between electrons is important is that allows for much less resistance to the flow of electrons down the electromagnetic field i.e. it takes less voltage and power to produce a longer chain of excited atoms. Well now that we, that includes me, have a vague idea of what's going on let's proceed to explain how to build one of these things. Let's start with the vacuum chamber as stated before I used a Thick Glass 5 gallon watercooler bottle this is an excellent choice though certainly not the only one. One could use a liquor bottle, section of acrylic tube, a bell jar, or anyone of many more suitable devices. Whatever you choose to use however remember that the walls of the container will be under tremendous forces if you acquired a vacuum pumpit could easily crack a piece of pressure rated PVC pipe.also the larger the container for more likely it is to employment Safety Glasses are a must and they face shield should be used. Keep in mind when selecting your container that you will need an easy way of sealing it and inserting a small tube with a valve. I use a piece of quarter inch refrigerater tubing with a beagle valve attached to one end. on the other end of the refrigerator tubing I slide a single hole stopper that will fit snugly into the mouth of my watercooler bottle. for my two poles I use the copper tubing had one and an on the other I place a sheet of aluminum foil. These two poles are wired to the outputs of two ignition coils. See links below for a schematic. The drive circuit is a simple oscillator based off the 555 timer. This square wave oscillator is used to switch a mental oxide field effect transistor that feeds the two ignition coils which are wired in antiparallel. The power source should be between 12 and 24 volts although from six too 36 volts will work. It is nice to use, or at least have available a six volts supply when testing the circuit and coils so when you get shocked, and you will, it won't hurt quite so bad. Remember if you're powering the circuit with more than 12 volts you need to have a regulator to control power feed to the 555 timer. Also the frequency output of the timer is easily controlled by via a timing capacitor and potentiometer. see links below for a schematic. Helpful Hits: No. 1: When adjusting the output frequency of the oscillator for maximum coil power is convenient to have a small adjustable spark gap made from two L brackets and two boltsspace with nuts. No. 2: If you plan on running more than 12 volts through your metal oxide field effect transistor or if you plan on running the system for more than 30 seconds at time is advisable to use a small cooling fan and heat sink on the metal oxide field effect transistor. No. 3: When trying to produce an environment of a pure gas such as helium is often advisable to evacuate the tube, return the tube to toatmospheric pressure with helium, evacuate the tube again, returned the two to atmospheric pressure with helium again, and evacuate won the last time. This will give you on an almost pure environment of helium. No. 4: Simply forget all this craziness about building and evacuation chamber. And by large clear lightbulb! This will work well however the glass on these bulbs is thin and will shatter its overstressed or heated. No. 5: Most importantly of all he should get a book on basic electronics and or electricity and read it. |
| evacuation tube |
| pictures with the lights on |