IN-12B (ИН-12Б) — Soviet Nixie Tube

The IN-12B is a Soviet-era numeric Nixie tube manufactured by Reflector (USSR). It is a cold-cathode gas-discharge display tube designed to show digits 0–9, with each digit formed from individually shaped wire cathodes stacked inside a glass envelope.

Unlike the IN-12A version, the IN-12B includes an additional left-hand decimal point, making it suitable for measurement instruments, counters, clocks, and panel displays where fractional values are required.

The tube operates with a typical striking voltage around 170 V and a maintaining voltage of approximately 140 V, with recommended operating current in the 2–4 mA range per digit. It features a common anode construction and standard wire leads for through-hole mounting.

Produced in the late Soviet period (datasheet dated 1988), the IN-12B remains popular today in DIY electronics projects, especially Nixie clocks and vintage-style instrumentation.