This document provides information on STC’s GN-1 Nixie tube. It includes a datasheet outlining the electrical specifications for both DC and rectified AC operation, as well as mechanical details such as tube dimensions and digit height. Additionally, it features circuit diagrams illustrating how the tube can be used in conjunction with the G10/241E counting tube. This document describes a very early version of the GN-1 without an anode grid. Later units included one, likely to achieve more even illumination.
This document details the design, functionality, and application of the STC G10-241E Nomotron, a unidirectional single pulse counting and display tube. It describes its operation and highlights its applications in areas such as tachometry, counting and batching, and frequency and time measurement. Besides a general overview over its mechanism of operation, it also contains detailed diagrams of the tube and example circuits for many of its aforementioned use cases.
Detail pictures of the G10/241E can be found here.
The STC G10/241E is an early neon-filled Nomotron counting tube allowing for up to 20,000 counts/second. It operates in a unidirectional, single-pulse mode, advancing the discharge by one position with each pulse and featuring ten stable positions. Unlike conventional decadic counting tubes (Dekatrons), its guiding electrodes are concealed behind a metal shell. Only the stable cathodes are visible through circular openings, each marked with its corresponding value on a transparent mica shield.
The GN-1, manufactured by STC and sold under the name ‘Nodistron’, was among the earliest commercially available Nixie tubes. The oldest documentation I could locate dates back to December 1959 (referenced below). The tube’s design reflects its age, with the digits being formed from wire rather than stamped from sheet metal like in most later Nixies. The GN-1 emits a distinctly orange glow, indicative of a mercury-free design, which likely results in a shorter lifespan compared to later models. Unlike more modern Nixie tubes, the GN-1 includes two evaporative getters, clearly visible on the left and right sides of the glass envelope. Additionally, its numerals are not mounted on a metal pin insulated by spacers but are instead secured between two mica plates and connected to the tube’s pins via thick wires. Interestingly, according to the datasheet, the tube has two anodes for use with direct and alternating currrent respectively.