Ramsey Electronics PG13 Instruction Manual page 10

To see an aurora closely, we can use Plasma balls. Plasma balls operate by
applying a high AC voltage to an electrode in the center of a glass sphere. This
high voltage must be high frequency AC in order for any current to get through
the glass of the globe and surrounding air by capacitive coupling to your hand
or the air. The current actually doesn't go through the glass, but is induced on
either side. Typical voltages are around a few thousand volts for most
commercial plasma globes, sometimes around 10,000 volts for some
homebrew ones. Typical frequencies are from a few kilohertz to a few tens of
kilohertz.
Plasma balls will usually employ unusual gases such as helium, neon, xenon,
krypton, and argon to achieve different colors and spark types. Since gases
usually ionize more easily at low air pressures, a plasma ball's air is first sucked
out with a vacuum pump, and then replaced with a mixture of the above gases
at about 1/10 to 1/20 of an atmosphere. These gases are noble gases, also
meaning inert, which means that they don't readily react with other molecules
and create dangerous results. There have been reports of Plasma balls working
at atmospheric pressure, and we may try that experiment here.
I used a small water-controlled vacuum pump at home when I was a kid and a
large, green wine bottle. The best I ever got was 4" streamers at the very
bottom, which were white due to the quantity of water vapor coming back
through my hose. When your budget is $20 a month, you simply can't afford a
vacuum pump.
Now that I have a job, I can get all of those toys I always wanted as a kid (if
my wife lets me!), but now I needed to make a new supply. My old one looked
like a rat's nest of wires, and the television flyback wouldn't fit in any plastic
case that I could find. It was time to make a new one that looked nice, and
didn't periodically shock me. I decided to use my resources here at work to
make a new kit as well as a new toy for me. (The wife won't stop me if the boss
is paying!)
Happy experimenting, and I hope you enjoy playing with high voltage as much
as I do! Oh, here is a little reference I pulled from the Internet on gases and the
colors they make. Pretty neat!
Colors and Effects of Various Gases (by Don Klipstein)
Helium - In spectrum tubes it glows a brilliant whitish yellow-orange color,
somewhat like that of a high pressure sodium lamp. I have heard that this
sometimes varies with pressure, current, and container dimensions.
Neon - Usually produces dim red blurry streamers with brighter orange "pads"
at the ends. If neon is mixed with another gas (other than helium), the streamer
color and character is often dominated by the other gas, but the ends of the
streamer are orange or pink "pads".
•
PG13 10