List of vacuum tubes

This is a list of vacuum tubes or thermionic valves, and low-pressure gas-filled tubes, or discharge tubes. Before the advent of semiconductor devices, thousands of tube types were used in consumer electronics. Many industrial, military or otherwise professional tubes were also produced. Only a few types are still used today, mainly in high-power, high-frequency applications and also in boutique guitar amplifiers.
Receiving tubes have heaters or filaments intended for direct battery operation, parallel operation off a dedicated winding on a supply transformer, or series string operation on transformer-less sets. High-power RF power tubes are directly heated; the heater voltage must be much smaller than the signal voltage on the grid and is therefore in the 5...25 V range, drawing up to hundreds of amperes from a suitable heater transformer. In some valve part number series, the voltage class of the heater is given in the part number, and a similar valve might be available with several different heater voltage ratings.
RETMA is the acronym for the Radio Electronic Television Manufacturers Association formed in 1953 - however the standard itself had already been in use since 1933, when RCA/Cunningham introduced the 1A6, 2A3, 2A5, etc.
Often designations that differed only in their initial numerals would be identical except for heater characteristics.
For examples see below
The system was used in 1942–44 and assigned numbers with the base form "1A21", and is therefore also referred to as the "1A21 system". The first numeric character indicated the filament/heater power rating, the second alphabetic character was a code for the function, and the last 2 digits were sequentially assigned, beginning with 21
For examples see below.
A four-digit system was maintained by JETEC since 1944, then by EIA since 1957 for special industrial, military and professional vacuum and gas-filled tubes, and all sorts of other devices requiring to be sealed off against the external atmosphere.
Some manufacturers preceded the EIA number with a manufacturer's code:
For examples see below.
Eitel/McCullough and other manufacturers of high power RF tubes use the following code since 1945:
Examples:
This system is very descriptive of what type of device (triode, diode, pentode etc.) it is applied to, as well as the heater/filament type and the base type (octal, noval, etc.). Adhering manufacturers include AEG (de), Amperex (us), CdL (1921, French Mazda brand), CIFTE (fr, Mazda-Belvu brand), EdiSwan (uk, British Mazda brand), Radiotechnique (fr, Coprim, Miniwatt-Dario and RTC brands), Lorenz (de), MBLE (be, Adzam brand), Mullard (uk), Philips (nl, Miniwatt brand), RCA (us), RFT (de), Siemens (de), Telefunken (de), Tesla (cz), Toshiba (ja), Tungsram (hu), Unitra (pl, Dolam, Polam and Telam brands) and Valvo (de).
This part dates back to the joint valve code key (German: Röhren-Gemeinschaftsschlüssel) negotiated between Philips and Telefunken in 1933–34. Like the North American system the first symbol describes the heater voltage, in this case, a Roman letter rather than a number. Further Roman letters, up to three, describe the device followed by one to four numerals assigned in a semi-chronological order of type development within number ranges assigned to different base types.
If two devices share the same type designation other than the first letter (e.g. ECL82, PCL82, UCL82) they will usually be identical except for heater specifications; however there are exceptions, particularly with output types (for example, both the PL84 and UL84 differ significantly from the EL84 in certain major characteristics, although they have the same pinout and similar power rating). However, device numbers do not reveal any similarity between different type families; e.g. the triode section of an ECL82 is not related to either triode of an ECC82, whereas the triode section of an ECL86 does happen to be similar to those of an ECC83.
Pro Electron maintained a subset of the M-P system after their establishment in 1966, with only the first letters E, P for the heater, only the second letters A, B, C, D, E, F, H, K, L, M, Y, Z for the type, and issuing only three-digit numbers starting with 1, 2, 3, 5, 8, 9 for the base.
Notes: Tungsram preceded the M-P designation with the letter T, as in TAD1 for AD1; VATEA Rádiótechnikai és Villamossági Rt.-t. (VATEA Radio Technology and Electric Co. Ltd., Budapest, Hungary) preceded the M-P designation with the letter V, as in VEL5 for EL5.
—Special quality:
For examples see below
Vacuum tubes which had special qualities of some sort, very often long-life designs, particularly for computer and telecommunications use, had the numeric part of the designation placed immediately after the first letter. They were usually special-quality versions of standard types. Thus the E82CC was a long-life version of the ECC82 intended for computer and general signal use, and the E88CC a high quality version of the ECC88/6DJ8. While the E80F pentode was a high quality development of the EF80, they were not pin-compatible and could not be interchanged without rewiring the socket (the E80F is commonly sought after as a high quality replacement for the similar EF86 type in guitar amplifiers). The letters "CC" indicated the two triodes and the "F", the single pentode inside these types.
A few special-quality tubes did not have a standard equivalent, e.g. the E55L, a broadband power pentode used as the output stage of oscilloscope amplifiers and the E90CC, a dual triode with a common cathode connection and seven pin base for use in cathode-coupled Flip-flops in early computers. The E91H is a special heptode with a passivated third grid designed to reduce secondary emission; this device was used as a "gate", allowing or blocking pulses applied to the first, (control) grid by changing the voltage on the third grid, in early computer circuits (similar in function to the U.S. 6AS6).
Many of these types had gold-plated base pins and special heater configurations inside the nickel cathode tube designed to reduce hum pickup from the A.C. heater supply, and also had improved oxide insulation between the heater and cathode so the cathode could be elevated to a greater voltage above the heater supply. (Note that elevating the cathode voltage above the average heater voltage, which in well-designed equipment was supplied from a transformer with an earthed center-tapped secondary, was less detrimental to the oxide insulation between heater and cathode than lowering the cathode voltage below the heater voltage, helping to prevent pyrometallurgical electrolytic chemical reactions where the oxide touched the nickel cathode that could form conductive aluminium tungstate and which could ultimately develop into a heater-cathode short circuit.)
Better, often dual, getters were implemented to maintain a better vacuum, and more-rigid electrode supports introduced to reduce microphonics and improve vibration and shock resistance. The mica spacers used in "SQ" and "PQ" types did not possess sharp protrusions which could flake off and become loose inside the bulb, possibly lodging between the grids and thus changing the characteristics of the device. Some types, particularly the E80F, E88CC and E90CC, had a constricted section of bulb to firmly hold specially shaped flakeless mica spacers.
For examples see below, starting at DC
Later special-quality tubes had not base and function swapped but were assigned a 4-digit number, such as ECC2000 or ED8000, the first digit of which again denoting the base:
For examples see below, starting at EC
"Z" Cold-cathode SQ tubes had a different function letter scheme:
For examples, see below under Z
In use since at least 1961, this system was maintained by Pro Electron after their establishment in 1966.
Both letters together indicate the type:
Then follows a 4-digit sequentially assigned number.
Optional suffixes for camera tubes:
Version letter:
Letter for variants derived by selection:
For examples see below
The first letter (or letter pair, in the case of a dual-system device) indicates the general type:
The following letter indicates the filament or cathode type, or the fill gas or other construction detail. The coding for vacuum devices differs between Philips (and other Continental European manufacturers) on the one hand and its Mullard subsidiary on the other.
The next letter indicates the cooling method or other significant characteristic:
The following group of digits indicate:
The following group of digits indicate the power:
An optional following letter indicates the base or connection method:
For examples see below
The first digit indicates the tube base:
The second digit is a sequentially assigned number.
The following letter indicates the photocathode type:
The following letter indicates the filling:
A following letter P indicates a photomultiplier.
Examples:
The first number indicates the burning voltage
The following letter indicates the current range:
The following digit is a sequentially assigned number.
An optional, following letter indicates the base:
Examples:
The first (1888) incarnation of La Compagnie des Lampes produced the TM tube since 1915 and defined one of the first French systems; not to be confused with Compagnie des Lampes (1921, "French Mazda", see below).
First letter: Heater or filament voltage
Second letter: Heater or filament current
Next number: Gain
Next number: Internal resistance in kΩ
Examples:
Note: EdiSwan also used the Mullard–Philips scheme.
First number: Heater or filament rating
Following letter or letter sequence: Type
Final number: Sequentially assigned number
Letter(s): Type
Number: Sequentially assigned number
Examples:
Note: "AC/"-series receiver tubes are listed under other letter tubes - AC/
This system consists of one or more letters followed by a sequentially assigned number
Examples:
The British Ericsson Telephones Limited (ETL), of Beeston, Nottingham (not to be confused with the Swedish TelefonAB Ericsson), original holder of the now-generic trademark Dekatron, used the following system:
Examples:
Note: More Nixie tubes under standard - ZM and professional - ZM
The British GEC–Marconi–Osram designation from the 1920s uses one or two letter(s) followed by two numerals and sometimes by a second letter identifying different versions of a particular type.
The letter(s) generally denote the type or use:
The following numbers are sequentially assigned for each new device.
Examples:
Older Mullard tubes were mostly designated PM, followed by a number containing the filament voltage.
Many later tubes were designated one to three semi-intuitive letters, followed by a number containing the heater voltage. This was phased out after 1934 when Mullard adopted the Mullard–Philips scheme.
Examples:
The system consisted of one letter followed by 3 or 4 digits. It was phased out after 1934 when Philips adopted the Mullard–Philips scheme.
1st letter: Heater current
1 or 2 digit(s): Heater voltage
Last 2 digits: Type
Examples:
First number: Type
Next letter: Heater rating
Number: Sequentially assigned number
Examples:
Valvo was a major German electronic components manufacturer from 1924 to 1989; a Philips subsidiary since 1927, Valvo was one of the predecessors of NXP Semiconductors.
The system consisted of one or two letters followed by 3 or 4 digits. It was phased out after 1934 when Valvo adopted the Mullard–Philips scheme.
First letter(s): Type
Number:
A following letter D indicates more than one grid, not counting a space charge grid
Examples:
Polish Lamina transmitting tube designations consist of one or two letters, a group of digits and an optional letter and/or two digits preceded by a "/" sign.
The first letter indicates the tube type, two equal letters denoting a dual tube:
A group of digits represents the maximum anode power dissipation in kW
An optional letter specifies the cooling method:
The first of the two digits after the "/" sign means:
The second digit after the "/" is sequentially assigned.
Examples:
Rundfunk- und Fernmelde-Technik was the brand of a group of telecommunications manufacturers in the German Democratic Republic. The designation consists of a group of three letters and a group of three or four digits.
The first two letters determine the tube type:
The third letter specifies the cooling method:
The first digit (or the first two digits in double tubes) indicates the number of electrodes:
The last two digits are sequentially assigned.
Examples:
Note: RFT used the Mullard–Philips and RETMA schemes for their low-power tubes.
Besides the genuine Mullard–Philips system, Tesla also used an M-P/RETMA hybrid scheme:
First number: Heater voltage, as in the RETMA system
Next letter(s): Type, subset of the Mullard–Philips system
Next digit: Base
Last digit: Sequentially assigned number
Examples:
First letter:
Next letter(s): Type, subset of the Mullard–Philips scheme
Next number: Anode dissipation in W (if radiation cooled) or kW (otherwise)
The next letter specifies the cooling method:
Examples:
The Tungsram system was composed of a maximum of three letters and three or four digits. It was phased out after 1934 when Tungsram adopted the Mullard–Philips scheme, frequently preceding it with the letter T, as in TAD1 for AD1.
Letter: System type:
Number:
Examples:
Vacuum tubes produced in the former Soviet Union and in present-day Russia are designated in Cyrillic. Some confusion has been created in transliterating these designations to Latin.
The first system was introduced in 1929. It consisted of one or two letters (designating system type and, optionally, type of cathode), a dash, then a sequentially assigned number with up to 3 digits.
In 1937, the Soviet Union purchased a tube assembly line from RCA (who at the time had difficulties raising funds for their basic operations), including production licenses and initial staff training, and installed it on the Svetlana/Светлана plant in St. Petersburg, Russia. US-licensed tubes were produced since then under an adapted RETMA scheme.
Examples:
In the 1950s a 5-element system (Russian: Государственный Стандарт "State standard" ГОСТ/GOST 5461–59, later 13393–76) was adopted in the (then) Soviet Union for designating receiver vacuum tubes.
The first element is a number specifying filament voltage. The second element is a Cyrillic letter specifying the type of device. The third element is a sequentially assigned number that distinguishes between different devices of the same type. The fourth element denotes the type of envelope. An optional fifth element consists of a dash followed by one or more characters to designate special characteristics of the tube. This usually implies construction differences, not just selection from regular quality production.
There is another designation system for professional tubes such as transmitter ones.
The first element designates function. The next elements varies in interpretation. For ignitrons, rectifiers, and thyratrons, there is a digit, then a dash, then the anode current in amperes, a slash, anode voltage in kV. A letter may be attached to designate water cooling (no letter designates a radiation cooled device). For transmitting tubes in this system, the second element starts with a dash, a sequentially assigned number, then an optional letter specifying cooling method. For phototubes and photomultipliers, the second element is a sequential number and then a letter code identifying vacuum or gas fill and the type of cathode.
A letter: Structure and usage
Then a letter: Base and outline
Then a dash, followed by a sequentially assigned number or the designation of the American original
Then an optional dash, followed by a letter: Version
Examples:
JIS C 7001 was published in 1951 and modified in 1965 and 1970
A number: Heater voltage range, as in the RETMA scheme
etc.
Then a letter: Base and Outline
Then a dash, followed by a letter: Structure and usage
Then a sequentially assigned number
Then an optional letter: Version
Examples:
This system prefixes a three- or four-digit number with the letters "CV", meaning "civilian valve" i.e. common to all three armed services. It was introduced during the Second World War to rationalise the previous nomenclatures maintained separately by the War Office/Ministry of Supply, Admiralty and Air Ministry/Ministry of Aircraft Production on behalf of the three armed services (e.g. "ACR~", "AR~", "AT~", etc. for CRTs, receiving and transmitting valves used in army equipments, "NC~", "NR~" and "NT~" similarly for navy equipments and "VCR~", "VR~" and "VT~" etc. for air force equipments), in which three separate designations could in principle apply to the same valve (which often had at least one prototype commercial designation as well). These numbers generally have identical equivalents in both the North American, RETMA, and West European, Mullard–Philips, systems but they bear no resemblance to the assigned "CV" number.
Examples:
The "CV4000" numbers identify special-quality valves though SQ valves CV numbered before that rule came in retain their original CV number:
The "M8" in the part number denotes that it was developed by the military:
The principle behind the CV numbering scheme was also adopted by the US Joint Army-Navy JAN numbering scheme which was later considerably expanded into the US Federal and then NATO Stock Number system used by all NATO countries. This part-identification system ensures that every particular spare part (not merely thermionic valves) receives a unique stock number across the whole of NATO irrespective of the source, and hence is not held inefficiently as separate stores. In the case of CV valves, the stock number is always of the format 5960-99-000-XXXX where XXXX is the CV number (with a leading 0 if the CV number only has 3 digits).
One system prefixes a three-digit number with the letters "VT", presumably meaning "Vacuum Tube". Other systems prefix the number with the letters "JHS" or "JAN". The numbers following these prefixes can be "special" four-digit numbers, or domestic two- or three-digit numbers or simply the domestic North American "RETMA" numbering system. Like the British military system, these have many direct equivalents in the civilian types. Confusingly, the British also had two entirely different "VT" nomenclatures, one used by the Royal Air Force (see the preceding section) and the other used by the General Post Office, responsible for post and telecommunications at the time, where it may have stood for "valve, telephone"; none of these schemes corresponded in any way with each other.
Examples:
Various numeral-only systems exist. These tend to be used for devices used in commercial or industrial equipment. The oldest numbering systems date back to the early 1920s, such as a two-digit numbering system, starting with the UV-201A, which was considered as "type 01", and extended almost continuously up into the 1980s. Three- and four-digit numeral-only systems were maintained by R.C.A., but also adopted by many other manufacturers, and typically encompassed rectifiers and radio transmitter output devices. Devices in the low 800s tend to be transmitter output types, those in the higher 800s are not vacuum tubes, but gas-filled rectifiers and thyratrons, and those in the 900s tend to be special-purpose and high-frequency devices. Use was not rigorously systematic: the 807 had variants 1624, 1625, and 807W.
There are quite a number of these systems from different geographical realms, such as those used on devices from contemporary Russian and Chinese production. Other compound numbering systems were used to mark higher-reliability types used in industrial or commercial applications. Computers and telecommunication equipment also required tubes of greater quality and reliability than for domestic and consumer equipment.
Some letter prefixes are manufacturer's codes:
For examples, see below
Some designations are derived from the behavior of devices considered to be exceptional.
Note: Typecode explained above. See also RETMA tube designation
First character is numeric zero, not letter O.
Function in a similar way to a Zener diode, at higher voltages. Letter order (A-B-C) indicates increasing voltage ratings on octal-based regulators and decreasing voltage ratings on miniature-based regulators.
The following tubes were used in post-World War II walkie-talkies and pocket-sized portable radios. All have 1.25 volt DC filaments and directly heated cathodes. Some specify which end of the filament is to be powered by the positive side of the filament power supply (usually a battery). All have glass bodies that measure from 0.285 to 0.400 inches (7.2 to 10.2 millimetres) wide, and from 1.25 to 2.00 inches (32 to 51 millimetres) in overall length.
These tubes were made for home storage battery receivers manufactured during the early to mid-1930s; all have 2.0 volt DC filaments despite the 1-prefix, intended to distinguish them from the 2.5 volt AC heated tubes listed below
Tubes used in AC-powered radio receivers of the early 1930s
These tubes all have 6.3 volt AC/DC heaters.
These tubes all have 12.6 volt AC/DC heaters
All of the following tubes are designed to operate with their heaters connected directly to the 117 volt (now 120 volt) electrical mains of North America. All of them use indirectly heated cathodes. All of them incorporate at least one rectifier diode.
The tubes in this list are most commonly used in series-wired circuits.
Note: Most of these are special quality versions of the equivalents given. Some manufacturers preceded the EIA number with a manufacturer's code, as explained above.
Note: Typecode explained above.
Note: See also standard M-P tubes under Z
Note: More Nixie tubes under standard - ZM and ETL examples
Note: Typecode explained above.
Not to be confused with Compagnie des Lampes (1888, see above) nor with British Mazda (see above).
The 1921 incarnation of La Compagnie des Lampes (since 1953 as Lampe Mazda) made light bulbs and electronic tubes under the French Mazda brand. Many of their tubes were also available from Compagnie Industrielle Française des Tubes Electroniques (CIFTE) under their Mazda-Belvu brand, which otherwise used mostly EIA, RETMA and Mullard–Philips tube designations.
Examples:
Before 1949:
Since 1949 with a fire pot logo:
Since 1953 as LAMPE MAZDA:
Since 1959 with a Faravahar logo related to Ahura Mazda:
Note: Typecode explained above.
Note: Typecode explained above.
Philips:
RCA:
Standard Telephones and Cables:
Edison and Swan Electric Light Company (British Mazda/EdiSwan):
Mazda/EdiSwan 4-volts AC, indirectly heated receiver tubes:
Marconi-Osram Valve Company
Industrial Electronic Engineers:
Burroughs Neon-filled planar glow-transfer plasma bar graph displays:
British Thomson-Houston (General Electric subsidiary):
Tung-Sol:
Raytheon:
Ferranti:
Philips:
Mullard:
Cerberus:
Ferranti:
Standard Telephones and Cables/Brimar:
Cerberus:
Ferranti:
Cerberus:
Ferranti:
Cerberus:
Ferranti:
Edgerton, Germeshausen, and Grier:
"Tung-Sol":
Philips:
Edison and Swan Electric Light Company (British Mazda/EdiSwan):
Edison and Swan Electric Light Company (British Mazda/EdiSwan):
Philips:
Philips:
Raytheon:
Marconi-Osram Valve Company:
Raytheon:
Radio Corporation of America:
Cossor:
British General Electric Company:
Standard Telephones and Cables/Brimar:
Compagnie Française Thomson-Houston:
E.C.&A. Grammont and Compagnie des Lampes (1888):
Bendix:
Marconi-Osram Valve Company:
Ferranti:
Used with AC, DC or home-based storage battery power supplies (1927–31)
Used in 1920s home radios. Filaments powered by 1.5 volt dry cells, anodes powered by storage batteries.
Used in 1930s home radios powered by storage batteries.
Used in 1920s home radios powered by dry cells (filaments) and storage batteries (B-plus voltage).
Used in 1920s home radios powered by storage batteries.
Powered by an AC transformer
Powered by an AC transformer or a vehicle crank battery
In the early 1930s, the Grigsby-Grunow Company – makers of Majestic brand radios – introduced the first American-made tubes to incorporate metal shields. These tubes had metal particles sprayed onto the glass envelope, copying a design common to European tubes of the time. Early types were shielded versions of tube types already in use. (The shield was connected to the cathode.) The Majestic numbers of these tube types, which are usually etched on the tube's base, have a "G" prefix (for Grigsby-Grunow) and an "S" suffix (for shielded). Later types incorporated an extra pin in the base so that the shield could be connected directly to the chassis.
Replacement versions from other manufacturers, such as Sylvania or General Electric, tend to incorporate the less expensive, form-fitting Goat brand shields that are cemented to the glass envelope.
Grigsby-Grunow did not shield rectifier tubes (except for type 6Y5 listed below) or power output tubes.