Neon gas filling at low pressure. (90V to 180V strike, 55V to 80V sustain). No filament.
Indicator, many styles not just the pair of rods
Bargraph such as Russian IN-9, IN-13 (4mA=FSD)
7 segment (numbers) or starburst (alphanumeric), Also known as Panaflex.
- Nixie (i.e. a shaped letter, digit or symbol for each electrode)
Counter/display such as Dekatron.
Cold Cathode Miniature Thyratron (3 rd “trigger” pin). (Not really indicators, but they glow)
High Voltage Regulator. (Not really indicators, but they glow)
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.
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.
A-101 A101 Dekatron
Dekatrons are counters and displays
10 dot, bidirectional count, Argon, Purple glow
10 dot, bidirectional count, Neon, Orange glow
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
Matheron and Dekatron at The Vintage Technology Association
Planaplex 7 segment Neon digits.
Another Nixie Clock Project
Neon Nostalgia at Onno’s Electric Page.