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48-479: A seven-segment display is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix displays . Seven-segment displays are widely used in digital clocks , electronic meters, basic calculators, and other electronic devices that display numerical information. Seven-segment representation of figures can be found in patents as early as 1903 (in U.S. patent 1,126,641 ), when Carl Kinsley invented

96-415: 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

144-458: 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 derivation from a split-anode magnetron . Trochotrons were used in the UNIVAC 1101 computer, as well as in clocks and frequency counters. The first trochotrons were surrounded by

192-465: 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 semiconductor integrated circuits typically use, 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

240-411: 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.

288-413: A fragile glass envelope. LEDs use less power than VFDs or Nixie tubes with the same function. Citing dissatisfaction with the aesthetics of modern digital displays and a nostalgic fondness for the styling of obsolete technology, significant numbers of electronics enthusiasts have shown interest in reviving Nixies. Unsold tubes that have been sitting in warehouses for decades are being brought out and used,

336-456: A full area (usually a rectangle ) are also called video displays , since it is the main modality of presenting video . Full-area 2-dimensional displays are used in, for example: Underlying technologies for full-area 2-dimensional displays include: The multiplexed display technique is used to drive most display devices. Nixie tube A Nixie tube ( English: / ˈ n ɪ k . s iː / NIK -see ), or cold cathode display ,

384-420: 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

432-593: A limited number of segments in seven-segment displays, a couple of the hexadecimal digits are required to be displayed as lowercase letters, otherwise the uppercase letter "B" would be the same as the digit "8", and the uppercase letter "D" would be the same as the digit "0". The digit "6" must also be displayed with the topmost segment as [REDACTED] to avoid ambiguity with the letter "b". Early decoder IC's often produced random patterns or duplicates of digits for 10-15, as they were designed to use as few gates as possible and only required to produce 0-9. Many letters of

480-440: A method of telegraphically transmitting letters and numbers and having them printed on tape in a segmented format. In 1908, F. W. Wood invented an 8-segment display, which displayed the number 4 using a diagonal bar ( U.S. patent 974,943 ). In 1910, a seven-segment display illuminated by incandescent bulbs was used on a power-plant boiler room signal panel. They were also used to show the dialed telephone number to operators during

528-496: 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 determined by the direction of the magnetic field, and as such was not reversible. A later form of trochotron called a Beam-X Switch replaced the large, heavy external cylindrical magnet with ten small internal metal-alloy rod magnets which also served as electrodes. Glow-transfer counting tubes, similar in essential function to

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576-447: A rectangle, with two vertical segments on each side and one horizontal segment each at the top, middle, and bottom. Often the rectangle is oblique (slanted), which may aid readability. In most applications, the segments are of nearly uniform shape and size (usually elongated hexagons , though trapezoids and rectangles can also be used); though in the case of adding machines , the vertical segments are longer and more oddly shaped at

624-734: A restricted range of letters that look like (upside-down) digits, seven-segment displays are commonly used by school children to form words and phrases using a technique known as " calculator spelling ". Seven-segment displays may use a liquid-crystal display (LCD), a light-emitting diode (LED) for each segment, an electrochromic display , or other light-generating or -controlling techniques such as cold cathode gas discharge (neon) ( Panaplex ), vacuum fluorescent (VFD), incandescent filaments (Numitron), and others. For gasoline price totems and other large signs, electromechanical seven-segment displays made up of electromagnetically flipped light-reflecting segments are still commonly used. A precursor to

672-461: A seven-segment digit template , to compose figures such as product prices or telephone numbers. For many applications, dot-matrix liquid-crystal displays (LCDs) have largely superseded LED displays in general, though even in LCDs, seven-segment displays are common. Unlike LEDs, the shapes of elements in an LCD panel are arbitrary since they are formed on the display by photolithography . In contrast,

720-445: A seven-segment display, including the decimal point. The most popular bit encodings are gfedcba and abcdefg . In the gfedcba representation, a byte value of 0x06 would turn on segments "c" and "b", which would display a "1". The numerical digits 0 to 9 are the most common characters displayed on seven-segment displays. The most common patterns used for each of these are: Alternative patterns: The numeral 1 may be represented with

768-639: A simple LED package, typically all of the cathodes (negative terminals) or all of the anodes (positive terminals) of the segment LEDs are connected and brought out to a common pin; this is referred to as a "common cathode" or "common anode" device. Hence a 7 segment plus decimal point package will only require nine pins, though commercial products typically contain more pins, and/or spaces where pins would go, in order to match standard IC sockets. Integrated displays also exist, with single or multiple digits. Some of these integrated displays incorporate their own internal decoder , though most do not: each individual LED

816-403: A small subset of their total number of states), were trade named Selectron tubes. At least one device that functioned in the same way as Nixie tubes was patented in the 1930s . There were a number of relevant patents filed by Northrop and others around the early 1950s, and the first mass-produced display tubes were introduced in 1954 by National Union Co. under the brand name Inditron. However,

864-452: 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

912-451: Is an electronic device used for displaying numerals or other information using glow discharge . 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 a small amount of argon , in a Penning mixture . In later nixies, in order to extend

960-468: Is brought out to a connecting pin as described. Multiple-digit LED displays as used in pocket calculators and similar devices used multiplexed displays to reduce the number of I/O pins required to control the display. For example, all the anodes of the A segments of each digit position would be connected together and to a driver circuit pin, while the cathodes of all segments for each digit would be connected. To operate any particular segment of any digit,

1008-437: The latin alphabet can be reasonably implemented on a seven-segment display. Though not every letter is available, it is possible to create many useful words. By careful choice of words, one can sometimes work around unavailable letters. Uppercase letters "I", "O", "S", "Z" conflict with the common seven-segment representation of digits "1", "0", 5", "2", and the lowercase letter "g" with digit "9". Upper case I could be put on

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1056-430: 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

1104-437: The 1970s. Many early (c. 1970s) LED seven-segment displays had each digit built on a single die . This made the digits very small. Some included magnifying lenses in the design to try to make the digits more legible. Other designs used 1 or 2 dies for every segment of the display. The seven-segment pattern is sometimes used in posters or tags, where the user either applies color to pre-printed segments, or applies color through

1152-612: The 1980s, so Russian and Eastern European Nixies are still available. Other numeric-display technologies include 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

1200-426: The 5 being an upside down 2. The ИH-12B tubes feature a bottom far left decimal point between the numbers 8 and 3. 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

1248-462: The 7-segment display in the 1950s through the 1970s was the cold-cathode, neon-lamp-like nixie tube . Starting in 1970, RCA sold a display device known as the Numitron that used incandescent filaments arranged into a seven-segment display. In USSR, the first electronic calculator "Vega", which was produced from 1964, contains 20 decimal digits with seven-segment electroluminescent display . In

1296-496: 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 ИH-12A (IN-12A) and ИH-12B (IN-12B) tubes use the number arrangement 3 8 9 4 0 5 7 2 6 1 from front (3) to back (1), with

1344-423: The construction of the first Inditrons was cruder than that of the later Nixies, lacking the common anode grid, so that the unlit numerals were held at anode voltage to function as the effective anode. Their average lifetime was shorter, and they failed to find many applications due to their complex drive needs. The most common form of Nixie tube has ten cathodes in the shapes of the numerals 0 to 9 (and occasionally

1392-463: The controlling integrated circuit would turn on the cathode driver for the selected digit, and the anode drivers for the desired segments; then after a short blanking interval the next digit would be selected and new segments lit, in a sequential fashion. In this manner an eight digit display with seven segments and a decimal point would require only 8 cathode drivers and 8 anode drivers, instead of sixty-four drivers and IC pins. Often in pocket calculators

1440-502: The digit drive lines would be used to scan the keyboard as well, providing further savings; however, pressing multiple keys at once would produce odd results on the multiplexed display. Although to a naked eye all digits of an LED display appear lit, only one digit is lit at any given time in a multiplexed display. The digit changes at a high enough rate that the human eye cannot see the flashing (on earlier devices it could be visible to peripheral vision). The seven segments are arranged as

1488-528: 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 get activated. As testament to their longevity, and that of

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1536-461: The ends, to try to make them more easily readable. The seven elements of the display can be lit in different combinations to represent each of the Arabic numerals . The individual segments are referred to by the letters "a" to "g", and an optional decimal point (an "eighth segment", referred to as DP) is sometimes used for the display of non-integer numbers. A single byte can encode the full state of

1584-456: The equipment which incorporated them, as of 2006 several suppliers still provided common Nixie tube types as replacement parts, new in original packaging. Devices with Nixie-tube displays in excellent working condition are still plentiful, though many have been in use for 30 to 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

1632-536: 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

1680-945: The full ASCII character set were briefly available in the early 1980s but did not prove popular. Display device Common applications for electronic visual displays are television sets or computer monitors . These are the technologies used to create the various displays in use today. Some displays can show only digits or alphanumeric characters. They are called segment displays , because they are composed of several segments that switch on and off to give appearance of desired glyph . The segments are usually single LEDs or liquid crystals . They are mostly used in digital watches and pocket calculators . Common types are seven-segment displays which are used for numerals only, and alphanumeric fourteen-segment displays and sixteen-segment displays which can display numerals and Roman alphabet letters. Cathode-ray tubes were also formerly widely used. 2-dimensional displays that cover

1728-505: 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

1776-517: 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: Driving Nixies outside of their specified electrical parameters will accelerate their demise, especially excess current, which increases sputtering of

1824-439: The left (as lower-case L is shown here) but this is not often done. Lowercase 'b' and 'q' are identical to the alternate numerical digits '6' and '9'. The following are some real world english word examples seen on actual electronic equipment: There are also fourteen- and sixteen-segment displays (for full alphanumerics ); however, these have mostly been replaced by dot matrix displays . 22-segment displays capable of displaying

1872-678: The left segments, the numerals 6 and 9 may be represented without a "tail", and the numeral 7 represented with a 'tail': In Unicode 13.0, 10 codepoints had been given for segmented digits 0–9 in the Symbols for Legacy Computing block, to replicate early computer fonts that included seven-segment versions of the digits. The official reference shows the less-common four-segment "7". The binary-coded decimal (BCD) 0 to 9 digit values require four binary bits to hold their values. Since four bits (2) can hold 16 values, this means hexadecimal (hex) digits can be represented by four bits too. Since there are

1920-411: The most common application being in homemade digital clocks. 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, making small-scale production of new devices again viable. In addition to the tube itself, another important consideration

1968-498: 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. Nixie tubes were invented by David Hagelbarger. The early Nixie displays were made by

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2016-407: 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

2064-639: The shapes of LED segments tend to be simple rectangles , because they have to be physically moulded to shape, which makes it difficult to form more complex shapes than the segments of seven-segment displays. However, the easy recognition of seven-segment displays, and the comparatively high visual contrast obtained by such displays relative to dot-matrix digits, makes seven-segment multiple-digit LCD screens very common on basic calculators . The seven-segment display has inspired type designers to produce typefaces reminiscent of that display (but more legible), such as New Alphabet , "DB LCD Temp", "ION B", etc. Using

2112-401: 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

2160-763: The transition from manual to automatic telephone dialing. They did not achieve widespread use until the advent of LEDs in the 1970s. Some early seven-segment displays used incandescent filaments in an evacuated bulb; they are also known as numitrons. A variation (minitrons) made use of an evacuated potted box. Minitrons are filament segment displays that are housed in DIP ( dual in-line package ) packages like modern LED segment displays. They may have up to 16 segments . There were also segment displays that used small incandescent light bulbs instead of LEDs or incandescent filaments. These worked similarly to modern LED segment displays. Vacuum fluorescent display versions were also used in

2208-410: 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

2256-426: The usable life of the device, a tiny amount of mercury was added to reduce cathode poisoning and sputtering . Although it resembles a vacuum tube in appearance, its operation does not depend on thermionic emission of electrons from a heated cathode. It is hence 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

2304-477: The ИH-14 (IN-14), used an upside-down digit 2 as the digit 5, presumably to save manufacturing costs. 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

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