Neon Indicators and Nixies

  1. Neon gas filling at low pressure. (90V to 180V strike, 55V to 80V sustain). No filament.

    1. Indicator, many styles not just the pair of rods

    2. Bargraph such as Russian IN-9, IN-13 (4mA=FSD)

    3. 7 segment (numbers) or starburst (alphanumeric), Also known as  Panaflex.

    4. Nixie (i.e. a shaped letter, digit or symbol for each electrode)
    5. Counter/display such as Dekatron.

    6. Cold Cathode Miniature Thyratron (3 rd “trigger” pin). (Not really indicators, but they glow)

    7. High Voltage Regulator.  (Not really indicators, but they glow)

    8. Rare and poor operation Rod tuning(Tuneon) indicator. Tuneon 3184 by Cossor, similar 3180 & 4662, Flash-O-Graph, Tune-A-Lite, Tone-Beam and Tun-A-Lite. These are from 1931 till 1934/1935 when the first true “Magic Eye” 6E6 appeared.


    9. The extremelyrare VG1 annular neon tuning indicator. (identical to the Visi-glow) 1934

Due to the gas the Neon tube glass may eventually blacken. They can operate from AC or either polarity of DC but need a series limiting resistor and higher voltage to turn on (strike) and then the voltage drops. Below a certain sustain current the neon turns off, so using a DC supply, resistor and capacitor a relaxation oscillator is easily made. If the normally illuminated electrode is shaped, then the correct polarity of DC is required. Russian types are prefixed by IN or INS. Strictly speaking only the type with stacked electrodes in shape of digits are “Nixie Tubes”. Neon signs are actually usually not containing neon! Neon devices are also called “cold cathode” tubes as there is no filament.

Thyratrons are not normally indicators and also can be very large. There are many kinds. The higher power models have a heater and low power small ones are “cold cathode” neon. Thyratrons can be Mercury vapour, Neon, Hydrogen or other gas at low pressure. However there may be some value in using the sub-miniature Neon cold cathode Thyratrons as indicators. They can be used like Unijunction transistors or Thyristors.

Common Neon Indicators have two rods


Only one lights with DC, both light with AC.

Fantastic collection of Vintage Neon lamps at Mike’s Electric Stuff.



A-101 A101 Dekatron

Dekatrons are counters and displays

OG-3 Dekatron

10 dot, bidirectional count, Argon, Purple glow

OG-4 Dekatron

10 dot, bidirectional count, Neon, Orange glow


IN6 Nixie



IN22 Nixie


Radio Museum Neon Indicators

Vintage Neon lamps at Mike’s Electric Stuff.

Nixie Tube Clocks at Mike’s Electric Stuff. (Fabulous)

Using a Russian Neon Bargraph (IN-13)  as a Tuneon by Joe Sousa

The Nixie Clock Site

Nixies at Wikipedia

Neon Lamps at Wikipedia

Thyratron switches? Dekatrons, Nixies and the Anita 8 Calculator and other vintage at The Vintage Calculators Web Museum

Dekatrons at Wikipedia

Dekatrons at Mike’s Electric stuff, also here Mike’s Electric Stuff

Matheron and Dekatron at The Vintage Technology Association

Planaplex 7 segment Neon digits.

Another Nixie Clock Project

Neon Nostalgia at Onno’s Electric Page.