Nixie

A nixie tube is a gas-discharge display device used to show numerals. Inside a glass envelope, ten cathodes shaped as the digits 0 through 9 are arranged around a common anode. The tube is filled with a low-pressure gas, typically neon, sometimes with small amounts of other gases. When a suitable high voltage is applied to the anode and a single digit cathode is driven negative relative to the anode, that digit glows with an orange-red light.

Operation and design: The digits are individual cathodes; only the illuminated digit lights while the others stay dark. The glow arises from a cold-cathode glow discharge and requires a relatively high voltage, commonly around 170 to 180 volts DC, with a current of a few milliamperes per lit digit. To drive multiple digits, designers use multiplexing or separate high-voltage drivers to select each digit. The distinct glass envelope and neon glow give nixie displays their characteristic retro appearance, which is prized in vintage electronics and contemporary art projects.

History and use: Nixie tubes were developed in the 1950s and were widely used through the 1960s and 1970s in instrumentation, early digital clocks, calculators, and laboratory equipment. They were gradually supplanted by more efficient technologies such as LED, LCD, and later VFD displays. In recent years, nixie tubes have enjoyed a niche revival for retro clocks, art installations, and hobbyist builds, often paired with modern electronics and safe high-voltage supplies.

Safety and maintenance: Nixie tubes require careful handling due to their fragile glass envelopes and the need for high-voltage power supplies. Proper insulation and surge protection are important, and tube life can be affected by operating conditions and duty cycle.