How does a neon tube work?
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How Neon Lights Work (A Simple Explanation)
Simple Demonstration of Why Noble Gases Don't React
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'Open' neon sign at night
DigiPub/Getty Images
by
Anne Marie Helmenstine, Ph.D.
Updated January 25, 2019
Neon lights are colorful, bright, and reliable, so you see them used in signs, displays, and even airport landing strips. Have you ever wondered how they work and how different colors of light are produced?
Key Takeaways: Neon Lights
A neon light contains a tiny amount of neon gas under low pressure.
Electricity provides energy to strip electrons away from neon atoms, ionizing them. Ions are attracted to terminals of the lamp, completing the electric circuit.
Light is produced when neon atoms gain enough energy to become excited. When an atom returns to a lower energy state, it releases a photon (light).
How a Neon Light Works
A neon light consists of a glass tube filled with a small amount (low pressure) of neon gas. Neon is used because it is one of the noble gases. One characteristic of these elements is that each atom has a filled electron shell, so the atoms don't react with other atoms and it takes a lot of energy to remove an electron.
There is an electrode at either end of the tube. A neon light actually works using either AC (alternating current) or DC (direct current), but if DC current is used, the glow is only seen around one electrode. AC current is used for most neon lights you see.