The GC10B is a British neon-filled dekatron: a 10-cathode glow-transfer counting tube that both counts and shows the count. It was the first commercial dekatron, introduced by Ericsson Telephones Ltd in 1950. This example is marked Made in England. In the MicroBasement it sits with the GS10C/S and the Tesla Nomotron as the gas-tube way to count before cheap silicon counters existed.
Dekatrons were invented in the late 1940s by J.R. Acton at Ericsson Telephones Ltd. The first commercial type was this one, the GC10B, in 1950. They were used in the 1950s-1960s for counting, timing, frequency measurement, and decade scalers. The British GC/GS lines are ETL and licensees. Soviet factories made their own families; those are not this tube. Dekatrons faded in the 1970s as TTL and LEDs took over.
The GC10B is a cold-cathode gas tube with ten main cathodes in a ring and a common anode. A neon glow rests on one cathode. Guide electrodes walk that glow one step per pulse. The glowing spot is the digit. This is the parent of the later GS10C selector types, not a Soviet rebadge.
The GC10B operates on glow-discharge principles:
It was prized for its visual appeal, reliability, and self-contained counting/display in one tube.
Dekatrons like the GC10B were used in:
They provided a beautiful, glowing decimal readout without needing separate display tubes.
The GC10B is a collector favorite as the tube that started the dekatron line. In the MicroBasement it is the 1950 original next to the later GS10C/S: same idea, first production mark.