HISTORY OF THE NIXIE TUBE
Nixie tubes were originally developed in 1952 by the Haydu brothers for the Burroughs Corporation as the precursor to the computer monitor. The name "Numerical Indicator experimental: NIX-i" was first a working acronym belonging to the Burroughs company but became the common name for these readouts. From the early 1950's to the 1970's Nixie tubes were the dominant display service. Later they were supplanted by LED displays and are quite rare today! They found their way into everything from test equipment over early computers to aerospace and submarines or the display of the New York stock exchange. While LED's are technically more advanced, their aesthetics leave something to be desired. A Nixie's digits consist of ten thin metal electrodes that are individually formed and can easily incorporate uneven curves and skew lines. The only technical flaw is based on the fact that the digits are stacked in front of each other; this causes tiny gaps where they are shadowed by the digits in front of it. Ironically, they were hardly used as clock displays. Over recent years their popularity has increased dramatically due to their unusual appearance and historical value. In essence they are like miniature neon signs with a warm, comforting orange/violet glow. Nixie clocks have become very popular as a way to bring these devices 'out of the dark'.
Each glass tube typically contains 10 or more individual cathode wires in the shape of numbers or letters. The cathodes are stacked so that different numerals appear at different depths, unlike a planar display in which all numerals are on the same plane relative to the viewer. The anode is a transparent metal mesh wrapped around the front of the display. The tube is filled with the inert gas neon (and other gases) with a small amount of mercury. When an electric potential of 120 to 180 volts DC is applied between the anode and any cathode, the gas near the cathode breaks down and the digit spreads it's wonderfull glow.