A nixie tube is an electronic device for displaying numerals or other information. The glass tube contains a wire-mesh anode and multiple cathodes. In most tubes, the cathodes are shaped like numerals (0-9). Applying power to one cathode surrounds it with an orange glow discharge. The tube is filled with a gas at low pressure, usually mostly neon and often a little mercury and/or argon, in a Penning mixture.
Although it resembles a vacuum tube in appearance, it does not depend on thermionic emission of electrons from a heated cathode. It is therefore called a cold-cathode tube (a form of gas filled tube), or similar to a neon lamp. Nixie Tubes rarely exceed 104 °F.
There are also tubes of types that show various letters, signs and symbols. Some Russian nixies, e.g. the IN-14, used an upside-down digit 2 as the digit 5, presumably to save manufacturing costs as there is no obvious technical or aesthetic reason.
Each cathode can be made to glow in the characteristic neon red-orange color by applying about 170 volts DC at a few milliamperes between a cathode and the anode. The current limiting is normally implemented as an anode resistor of a few tens of thousands of ohms. Nixies exhibit negative resistance and will maintain their glow at typically 20 V to 30 V below the strike voltage. Some color variation can be observed between types, caused by differences in the materials and gas mixtures used. Longer-life tubes that were manufactured later in the nixie timeline have mercury added to reduce sputtering resulting in a blue or purple tinge to the emitted light. In some cases, these colors are filtered out by a red or orange pigment coating on the glass.
US $25.00
