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 tube features a specialized socket design based on the B12A socket, incorporating an additional central pin that connects to the tube’s anode.
This particular unit includes two handwritten markings: one labeled “162” in the center of the mica shield and another, “B129CW,” etched into the metal shell. The production of these tubes likely required significant manual craftsmanship.
A full scan of the document “STC Valves Appilcation Report - G10/241E” containing much more information on the tube can be found here.
Key Specifications
| Property | Description |
|---|---|
| Manufacturer | STC |
| Time period | mid 1950s |
| Filling | Neon |
| Counting speed | <20,000 c/s |
| Envelope diameter | 41mm |
| Socket | McMurdo type X12E |
References
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