Nixie tube (English: /ˈnɪk.siː/ NIK-see), or cold cathode
display, is an electronic device for displaying numerals or other
information using glow discharge.
Inside a Nixie tube
The glass tube contains a wire-mesh anode and multiple cathodes,
shaped like numerals or other symbols. Applying power to one cathode
surrounds it with an orange glow discharge. The tube is filled with a
gas at low pressure, usually mostly neon and often a little mercury or
argon, in a Penning mixture.
Although it resembles a vacuum tube in appearance, its operation does
not depend on thermionic emission of electrons from a heated cathode.
It is therefore called a cold-cathode tube (a form of gas-filled
tube), and is a variant of the neon lamp. Such tubes rarely exceed
40 °C (104 °F) even under the most severe of operating
conditions in a room at ambient temperature. Vacuum fluorescent
displays from the same era use completely different technology—they
have a heated cathode together with a control grid and shaped phosphor
anodes; Nixies have no heater or control grid, typically a single
anode (in the form of a wire mesh, not to be confused with a control
grid), and shaped bare metal cathodes.
3 Applications and lifetime
4 Alternatives and successors
6 See also
8 Further reading
9 External links
Systron-Donner frequency counter from 1973 with Nixie-tube display
The early Nixie displays were made by a small vacuum tube manufacturer
called Haydu Brothers Laboratories, and introduced in 1955 by
Burroughs Corporation, who purchased Haydu. The name Nixie was derived
by Burroughs from "NIX I", an abbreviation of "Numeric Indicator
eXperimental No. 1", although this may have been a backronym
designed to justify the evocation of the mythical creature with this
name. Hundreds of variations of this design were manufactured by many
firms, from the 1950s until the 1990s. The Burroughs Corporation
introduced "Nixie" and owned the name Nixie as a trademark. Nixie-like
displays made by other firms had trademarked names including Digitron,
Inditron and Numicator. A proper generic term is cold cathode neon
readout tube, though the phrase
Nixie tube quickly entered the
vernacular as a generic name.
Burroughs even had another Haydu tube that could operate as a digital
counter and directly drive a
Nixie tube for display. This was called a
"Trochotron", in later form known as the "Beam-X Switch" counter tube;
another name was "magnetron beam-switching tube", referring to their
similarity to a cavity magnetron. Trochotrons were used in the UNIVAC
1101 computer, as well as in clocks and frequency counters.
The first trochotrons were surrounded by a hollow cylindrical magnet,
with poles at the ends. The field inside the magnet had
essentially-parallel lines of force, parallel to the axis of the tube.
It was a thermionic vacuum tube; inside were a central cathode, ten
anodes, and ten "spade" electrodes. The magnetic field and voltages
applied to the electrodes made the electrons form a thick sheet (as in
a cavity magnetron) that went to only one anode. Applying a pulse with
specified width and voltages to the spades made the sheet advance to
the next anode, where it stayed until the next advance pulse. Count
direction was not reversible. A later form of trochotron called a
Switch replaced the large, heavy external cylindrical magnet
with ten small internal metal-alloy rod magnets which also served as
Nixie tube displays symbols, including % and °C
Glow-transfer counting tubes, similar in essential function to the
trochotrons, had a glow discharge on one of a number of main cathodes,
visible through the top of the glass envelope. Most used a neon-based
gas mixture and counted in base-10, but faster types were based on
argon, hydrogen, or other gases, and for timekeeping and similar
applications a few base-12 types were available. Sets of "guide"
cathodes (usually two sets, but some types had one or three) between
the indicating cathodes moved the glow in steps to the next main
cathode. Types with two or three sets of guide cathodes could count in
either direction. A well-known trade name for glow-transfer counter
tubes in the
United Kingdom was Dekatron. Types with connections to
each individual indicating cathode, which enabled presetting the
tube's state to any value (in contrast to simpler types which could
only be directly reset to zero or a small subset of their total number
of states), were trade named Selectron tubes.
Devices that functioned in the same way as Nixie tubes were patented
in the 1930s, and the first mass-produced display tubes were
introduced in 1954 by National Union Co. under the brand name
Inditron. However, their construction was cruder, their average
lifetime was shorter, and they failed to find many applications due to
their complex periphery.
The most common form of
Nixie tube has ten cathodes in the shapes of
the numerals 0 to 9 (and occasionally a decimal point or two), but
there are also types that show various letters, signs and symbols.
Because the numbers and other characters are arranged one behind
another, each character appears at a different depth, giving Nixie
based displays a distinct appearance. A related device is the pixie
tube, which uses a stencil mask with numeral-shaped holes instead of
shaped cathodes. Some Russian Nixies, e.g. the IN-14, used an
upside-down digit 2 as the digit 5, presumably to save manufacturing
costs as there is no obvious technical or aesthetic reason.
Each cathode can be made to glow in the characteristic neon red-orange
color by applying about 170 volts DC at a few milliamperes between a
cathode and the anode. The current limiting is normally implemented as
an anode resistor of a few tens of thousands of ohms. Nixies exhibit
negative resistance and will maintain their glow at typically 20 V to
30 V below the strike voltage. Some color variation can be observed
between types, caused by differences in the gas mixtures used.
Longer-life tubes that were manufactured later in the Nixie timeline
have mercury added to reduce sputtering resulting in a blue or
purple tinge to the emitted light. In some cases, these colors are
filtered out by a red or orange filter coating on the glass.
One advantage of the
Nixie tube is that its cathodes are
typographically designed, shaped for legibility. In most types, they
are not placed in numerical sequence from back to front, but arranged
so that cathodes in front obscure the lit cathode minimally. One such
arrangement is 6 7 5 8 4 3 9 2 0 1 from front (6) to back (1).
Russian NH-12A & NH-12B tubes use the number arrangement 1 6 2 7 5
0 4 9 8 3 from back to front, with the 5 being an upside down 2. The
12B tubes feature a bottom far left decimal point between the numbers
8 and 3.
Applications and lifetime
The stacked digit arrangement in a
Nixie tube is visible in this
Pair of NL-5441 Nixie display tubes
Nixies were used as numeric displays in early digital voltmeters,
multimeters, frequency counters and many other types of technical
equipment. They also appeared in costly digital time displays used in
research and military establishments, and in many early electronic
desktop calculators, including the first: the Sumlock-Comptometer
ANITA Mk VII of 1961 and even the first electronic telephone
switchboards. Later alphanumeric versions in fourteen segment display
format found use in airport arrival/departure signs and stock ticker
displays. Some elevators used Nixies to display floor numbers.
Average longevity of Nixie tubes varied from about 5,000 hours for the
earliest types, to as high as 200,000 hours or more for some of the
last types to be introduced. There is no formal definition as to what
constitutes "end of life" for Nixies, mechanical failure excepted.
Some sources suggest that incomplete glow coverage of a glyph
("cathode poisoning") or appearance of glow elsewhere in the tube
would not be acceptable.
Nixie tubes are susceptible to multiple failure modes, including
cracks and hermetic seal leaks allowing the atmosphere to enter,
cathode poisoning preventing part or all of one or more characters
increased striking voltage causing flicker or failure to light,
sputtering of electrode metal onto the glass envelope blocking the
cathodes from view,
internal open or short circuits which may be due to physical abuse or
Driving Nixies outside of their specified electrical parameters will
accelerate their demise, especially excess current, which increases
sputtering of the electrodes. A few extreme examples of sputtering
have even resulted in complete disintegration of Nixie-tube cathodes.
Cathode poisoning can be abated by limiting current through the tubes
to significantly below their maximum rating, through the use of
Nixie tubes constructed from materials that avoid the effect (e.g. by
being free of silicates and aluminum), or by programming devices to
periodically cycle through all digits so that seldom-displayed ones
As testament to their longevity, and that of the equipment which
incorporated them, as of 2006[update] several suppliers still provide
Nixie tube types as replacement parts, new in original
packaging. Equipment with Nixie-tube displays in
excellent working condition is still plentiful, though much of it has
been in frequent use for 30–40 years or more. Such items can easily
be found as surplus and obtained at very little expense. In the former
Soviet Union, Nixies were still being manufactured in volume in the
1980s, so Russian and Eastern European Nixies are still available.
Alternatives and successors
Other numeric-display technologies concurrently in use included
backlit columnar transparencies ("thermometer displays"), light pipes,
rear-projection and edge-lit lightguide displays (all using individual
incandescent or neon light bulbs for illumination), Numitron
incandescent filament readouts, Panaplex seven-segment displays,
and vacuum fluorescent display tubes. Before Nixie tubes became
prominent, most numeric displays were electromechanical, using
stepping mechanisms to display digits either directly by use of
cylinders bearing printed numerals attached to their rotors, or
indirectly by wiring the outputs of stepping switches to indicator
bulbs. Later, a few vintage clocks even used a form of stepping switch
to drive Nixie tubes.
Nixie tubes were superseded in the 1970s by light-emitting diodes
(LEDs) and vacuum fluorescent displays (VFDs), often in the form of
seven-segment displays. The VFD uses a hot filament to emit electrons,
a control grid and phosphor-coated anodes (similar to a cathode ray
tube) shaped to represent segments of a digit, pixels of a graphical
display, or complete letters, symbols, or words. Whereas Nixies
typically require 180 volts to illuminate, VFDs only require
relatively low voltages to operate, making them easier and cheaper to
use. VFDs have a simple internal structure, resulting in a bright,
sharp, and unobstructed image. Unlike Nixies, the glass envelope of a
VFD is evacuated rather than being filled with a specific mixture of
gases at low pressure.
Specialized high-voltage driver chips such as the 7441/74141 were
available to drive Nixies. LEDs are better suited to the low voltages
that integrated circuits used, which was an advantage for devices such
as pocket calculators, digital watches, and handheld digital
measurement instruments. Also, LEDs are much smaller and sturdier,
without a fragile glass envelope. LEDs use less power than VFDs or
Nixie tubes with the same function.
A Nixie clock with six ZM1210 tubes made by Telefunken.
A Nixie watch on the wrist of Steve Wozniak, co-founder of Apple Inc.
Citing dissatisfaction with the aesthetics of modern digital displays
and a nostalgic fondness for the styling of obsolete technology,
significant numbers of electronics enthusiasts in recent years have
shown interest in reviving Nixies. Unsold tubes that have been
sitting in warehouses for decades are being brought out and used, the
most common application being in homemade digital clocks.
This is somewhat ironic, since during their heyday, Nixies were
generally considered too expensive for use in mass-market consumer
goods such as clocks. This recent surge in demand has caused prices
to rise significantly, particularly for large tubes. The largest Nixie
tubes known to be in the hands of collectors, the Rodan CD47/GR-414
(220 mm [8.7 in] tall), have been sold for hundreds of
dollars each, but said Nixies are extremely rare. Prices for other
large Nixies displaying digits over 25 mm (1 in) tall have
risen by double, triple or more between 1998 and 2005.[citation
There have also been some attempts to make new Nixie tubes, the most
successful of which is that of Dalibor Farny, a programmer and
electrical engineer from the Czech Republic. His efforts began in
February 2012, and by the end of 2014, Dalibor had created his first
marketable Nixie tube, the RZ568M (whose "R" stands for
"resurrection"), which he still sells on his website for $145
In addition to the tube itself, another important consideration is the
relatively high-voltage circuitry necessary to drive the tube. The
7400 series drivers integrated circuits such as the 74141 BCD
decoder driver have long since been out of production and are rarer
than NOS tubes. Only "Integral" in
Belarus lists the 74141 and its
Soviet equivalent, the K155ID1  as still in production. However
modern bipolar transistors with high voltage ratings are now available
cheaply, such as MPSA92 or MPSA42 – an unusual example where an
original IC design has been replaced by discrete transistors.
Vacuum fluorescent display
Calculator Displays Archived 2013-08-22 at the Wayback Machine.
^ a b (Weston 1968, p. 334)
^ (Bylander 1979, p. 65)
^ a b (Bylander 1979, p. 60)
^ 'Solid State Devices--Instruments' article by S. Runyon in
Electronic Design magazine vol. 24, 23 November 1972, p. 102, via
Electronic Inventions and Discoveries:
Electronics from its Earliest
Beginnings to the Present Day, 4th Ed., Geoffrey William Arnold
Dummer, 1997, ISBN 0-7503-0376-X, p. 170
^ Scientific American, June 1973, p. 66
^ a b c "Home of the
Nixie tube clock". nixieclock.net. Archived from
the original on 2012-01-18. Retrieved 2017-09-20.
^ a b "KD7LMO - Nixie Tube Clock - Overview". ad7zj.net. 2014-01-17.
Archived from the original on 2017-07-14. Retrieved 2017-09-20.
^ "KD7LMO - Nixie Tube Clock - Hardware". ad7zj.net. 2014-01-17.
Archived from the original on 2017-06-21. Retrieved 2017-09-20.
^ "Chronotronix V300 Nixie Tube Clock User Manual" (PDF).
nixieclock.net. p. 6. Archived from the original (PDF) on
2012-01-05. Retrieved 2017-09-20.
Numitron Readout Archived 2007-10-19 at the Wayback Machine.
^ Zorpette, Glenn. "New Life For Nixies". IEEE Spectrum. Archived from
the original on 2009-08-31. Retrieved 2010-01-31.
^ "Nixie Tube Clocks". nixieclock.net. Archived from the original on
2007-08-08. Retrieved 2017-09-20.
^ Rodan CD47 tube Archived 2007-10-24 at the Wayback Machine.
^ a b "RZ568M Nixie Tube Nixie clocks at DaliborFarny.com".
www.daliborfarny.com. Archived from the original on 2017-06-06.
^ "IN74141N". Integral. Archived from the original on 14 January 2018.
Retrieved 19 October 2017.
^ "К155ИД1" [K155ID1] (in Russian). Integral. Archived from the
original on 16 September 2016. Retrieved 19 October 2017.
Bylander, E.G. (1979), Electronic Displays, New York: McGraw Hill,
ISBN 0-07-009510-8 , LCCN 78-31849.
Dance, J.B. (1967), Electronic Counting Circuits, London: ILIFFE Books
Ltd , LCCN 67-13048.
Weston, G.F. (1968), Cold
Cathode Glow Discharge Tubes, London: ILIFFE
Books Ltd , LCCN 68-135075, Dewey 621.381/51, LCC TK7871.73.W44.
Wikimedia Commons has media related to Nixie tubes.
Brief history of Haydu Brothers
Mike's Electric Stuff: Display and Counting Tubes
Nixie tube photos and datasheets (in English) (in German)
Nixie tube cross-reference tables
Giant Nixie Tube Collection partly (in English) (in German)
Virtual Nixie-tube devices on-line: Nixie display, clock, calculator
Nixie and Scope Clocks
Some Examples of Nixie Tubes used in homemade clocks
The Art of Making a Nixie Tube
Electroluminescent display (ELD)
Light emitting diode display (LED)
Cathode ray tube (CRT) (Monoscope)
Liquid-crystal display (LCD)
Plasma display panel (PDP)
Digital Light Processing
Digital Light Processing (DLP)
Liquid crystal on silicon
Liquid crystal on silicon (LCoS)
Organic light-emitting diode (OLED)
Organic light-emitting transistor (OLET)
Surface-conduction electron-emitter display
Surface-conduction electron-emitter display (SED)
Field emission display (FED)
Quantum dot display
Quantum dot display (QD-LED)
Ferro liquid crystal display (FLCD)
Thick-film dielectric electroluminescent technology (TDEL)
Telescopic pixel display (TPD)
Laser-powered phosphor display (LPD)
Vacuum fluorescent display
Vacuum fluorescent display (VFD)
Light-emitting electrochemical cell (LEC)
Seven-segment display (SSD)
Fourteen-segment display (FSD)
Sixteen-segment display (SISD)
History of display technology
Large-screen television technology
Optimum HDTV viewing distance
High-dynamic-range imaging (HDRI)
Color Light Output
Comparison of display technology
Bipolar junction transistor
Bipolar junction transistor (BJT)
Field-effect transistor (FET)
Constant-current diode (CLD, CRD)
Heterostructure barrier varactor
Insulated-gate bipolar transistor
Insulated-gate bipolar transistor (IGBT)
Integrated circuit (IC)
Light-emitting diode (LED)
Silicon controlled rectifier
Silicon controlled rectifier (SCR)
Unijunction transistor (UJT)
Pentagrid (Hexode, Heptode, Octode)
Vacuum tubes (RF)
Backward-wave oscillator (BWO)
Crossed-field amplifier (CFA)
Inductive output tube
Inductive output tube (IOT)
Traveling-wave tube (TWT)
Cathode ray tubes
Beam deflection tube
Magic eye tube
Video camera tube
audio and video