How does nixie tube works?
In spite of the fact that I was born in the middle of 90th, and never ever visited the USA yet, I feel unexplainable nostalgic for the spirit of New York city in 70th. Neon commercial signs, vintage cars, the spirit of steam punk in every corner, greenish industrial mist that breaks out of the manholes… I like to think about those times, and that’s one of the reasons why I work with the nixie tubes.
So, what is a nixie tube?
You probably have dozens of devices in your house, that display numbers. You face them every day: alarm clocks, microwave oven, calculators, any electronic device that has a screen with the timer. Usually they show blue-color numbers, it means that they are made of vacuum fluorescent displays (VFDs).
Or they can also be colored in red-orange, which eventually means that they are made of light emmiting diods (LEDs).
Both of them work by lighting up several bars, which composes the number. Only seven simple bars lighted in different ways may create any digit from 0 to 9. Like this:
Nixie tubes work in different way, they also can show you digits from 0 to 9, though, they don’t use any bars to be light up and compose a digit. The nixie tube contains all 10 decimal digits in it, each and every digit is made of bent wire. They are inserted into air-proof glass bulb filled with the neon gas. The digits are located in front or behind another digit inside the bulb.
Nixie tube bulb has a lot of contacts underneath, they can be called ‘legs’. These contacts are usually 1 cm+ long and connect to electronic circuit that is programmed to show you digits.
How does it work? Step by step:
Step 1: Nixie tube lamp has a lot in common with the neon lamp. There is a neon gas inside the glass bulb, and it is in a low-pressure. If you will add a high voltage the molecules of the gas inside the bulb will split into ions and electrons.
Step 2: All the ions that have positive charge strain after the negatively charged cathodes. Ions press the molecules of the neon gas into the cathode.
Step 3: All negatively charged electrons strain after positively charged anodes. In spite of the fact that there are much more free electrons then ions near the cathode, they are very week and slow, so their mutual impact is not enough to make a light, and this area stays dark. It is called the Aston dark space.
Step 4: The atoms of the metal are being strike out from the wire. This process may be called a “sputtering”.
Step 5: Within short enough distance of the cathode the electrons become faster, and when they smash with the sputtered atoms of metal here, they produce the light. This is that cozy light that you may see inside your nixie tube lamp. Like this: