How Do Neon Signs Work?

Neon is an inert gas. Basically, inert gases tend to keep their molecular structure. What is interesting about neon and other inert gases, is that they remain inert only in chemical reactions...not in glass tubes with electrodes like neon signs.

Why is this? Well, the electrodes in a neon sign discharge voltage through the gas in the discharge tube. The voltage that shoots through the gas will speed up any free electrons, which in turn builds the kinetic energy in the tube. When the kinetic energy is high enough, the neon atom becomes ionized. Ionization happens with an electron either jumps up to the next electron orbit, or down to the next electron orbit. What ionization does is give an inert gas a positive or negative charge. That charge creates a plasma (sort of a superheated gas/liquid) that carries the electrical impulse from one end of the tube to the other. This completes the electrical circuit.

When the circuit is complete, the electrons that were "excited" fall to their regular energy level. When this occurs, a photon is emitted, creating the glowing light we are all familiar with. A photon is a light particle/wave (physicists are still up in the air about which it is), and as long as the photon is within our visible light spectrum we can see it.

Pretty cool, huh?

For a more in-depth, sciency explanation please see The Physics of Neon.

Neon doesn't actually change colors. In fact, many people don't know that not all of neon signs actually use the inert gas, neon. Some use Helium, Argon, and Xenon. Neon, when properly heated using the method described above, glows a bright orange/red. For a light blue color, Mercury is used instead of Neon. When Argon is mixed with phosphor, the light emitted is a bold yellow glow. Argon is frequently mixed with other elements because it gives off a very bold glow. Carbon dioxide is used for white "neon" signs, and is also generally mixed with other elements. Helium provides a bold gold glow. All of these elements and gases can be intermixed to produce as many as 150 colors! Needless to say, after good ol' Georges Claude discovered and patented the neon discharge light...people got creative.

There is a good use for neon signs all over the place. Mostly, businesses like to use them to promote their products because neon signs are so eye-catching. Sports bar owners hang tons of neon signs, not only to catch the attention of passersby, but also because the glow of neon is almost expected in a bar atmosphere. Plus, if you are a sports bar, you have to promote some team spirit, right? NFL neon signs are perfect for sports bars and game rooms. The light feels very familiar and cozy, so they are very popular in bars. Many people with game rooms, rec rooms or basement sports bars like to hang neon signs for the same reason...it just kind of goes with the territory.

Many artists are realizing just how versatile neon lights are. People are making huge sculptures out of neon discharge tubes and then lighting them up. When it comes to neon signs, creativity is almost boundless...you just need a place to plug it in!