NIXIE INDICATORS AND DECIMAL COUNTING TUBES
by Tom Jennings

Nixie indicators (aka "Nixie tubes") were an all- electronic display device developed by Burroughs Corp in 1954 from a design by the Haydu brothers a year earlier. Nixies were a novel use of tried-and-true technologies == vacuum tube packaging of gaseous-discharge lamps ("neon lamps") shaped into alphanumeric symbols. Until the late '60's when supplanted by LEDs (then LCDs), Nixies were the premier display technology for low-bandwidth information.

A Nixie contained up to 12 symbols; most commonly digits 0 through 9, others with sign (+, -), decimal point or even alphas. Characters were cursive, discrete, fully formed, and a bright orange color.

Nixies were nicely synergistic, bridging the pre- computer world with the post. For the first time, instrumentation could display numbers as people drew them == nicely formed digits in a linear left-to-right string, with leading sign and decimal point. They were a monolithic electronic device rather than a mechanical assembly or array of lamps. Texas Instruments and others made TTL integrated-circuit interfaces for them, the 7440 and 7441.

Nixies are related to another dead computing/display technology == decimal counting tubes, inherently- computational devices tried in the crazy days of early computing, (about 1935-1955). Decimal tubes performed functions otherwise requiring a chassis full of tubes and discrete components. A decimal tube "effectively replac[es] 18 transistors (10 high voltage ones) and forty diodes" == a Good Thing in 1954. The design life of decimal counting tubes was fairly long == late 40's through early 60's.

Gaseous decimal counting tubes were also a medium unto themselves. They directly displayed their internal state via visibly-glowing electrodes, which commercial equipment used to advantage, mainly in counters and scalers.

Further details and limited bibliography are available on http://www.wps.com.

Tom Jennings (tomj@wps.com)