How does a neon tube work?

1 Answer
Aug 12, 2017

A neon tube is essentially controlled lightning in a glass tube filled with the appropriate elements to produce a desired color.


A neon light starts out as a glass tube that can be curved into all kinds of shapes using open flame heating on the glass where the bend is to be made. glass blowers and glass artists can provide an endless number of shapes.

The glass tube is then evacuated and refilled with neon gas, or gases of carbon dioxide, helium, hydrogen or mercury, as well as mixtures of these, to obtain different colors.

Electrodes are then melted into the glass at either end so a very high voltage (20,000V an up) can be applied across the tube. The high voltage is generated by a transformer, used to transform normal building voltage up to the higher level. The high voltage is required to force the electrons to jump the gas gap formed by the tube.

When the switch is turned on and the voltage is applied, it causes electrons to jump the gap to complete the circuit. As the electrons fly through the gas, they collide with the molecules of the gas. This excites the gas electrons, which in turn leap to higher orbitals and shoot off photons in colors specific to the gas. Some tubes have a phosphor coating, which will alter the light produced, as well as adding more possible colors.

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