Ramsey Electronics PG13 Instruction Manual page 11

Carbon Dioxide - Glows a whitish or blue-white color. It is probably good to
have no direct contact with metal electrodes for long life with gases that are not
completely inert. Carbon dioxide probably requires more voltage than the noble
gases. Generally, gases and vapors with monoatomic molecules work with less
voltage than others.
Nitrogen - Streamers are usually a whitish or grayish pink or light orange. The
color may be more gray or lavender at very low currents. The apparent color
varies with what kind of lighting it is in contrast with. Requires somewhat higher
voltage than noble gases.
Air, Oxygen, Water Vapor - These require more voltage than the noble gases
and do not glow brightly. I do not recommend these. If you must use any of
these, you may also want no direct contact of gas or vapor to metal in order to
avoid corrosion problems.
Argon - Streamers are violet-lavender. The ends are blue-violet-lavender.
Argon and neon. A mixture of around 99.5 percent neon, .5 percent argon has
the lowest voltage requirement, but may not look as good as other gases.
Argon-Nitrogen mixture (as found in many light bulbs) - Streamers are whitish
or grayish pink or orange, but more lavender at low currents. The ends are
blue-violet-lavender. Requires a bit more voltage than pure argon.
Krypton - Generally lightning-like and close to white or light gray, sometimes
purplish or pinkish, depending on background lighting. Sometimes fuzzier and/
or gray-greenish, especially if the pressure and/or peak current are low.
Xenon - Usually lightning-like and bluish white or bluish gray. May get fuzzier
and more gray or lavenderish gray at lower pressure and lower peak current.
Peak currents over a few milliamps favor a more lightning-like appearance even
if the RMS current is less than a milliamp.
Don Klipstein's web site with plenty of great information on HV and plasma:
http://www.misty.com/people/don/index.html
•
PG13 11