This is a list of vacuum tubes or thermionic valves. For every commonly recognizable contemporary type, more than 300 different types existed 50 years ago. |
Numbering SystemsNorth American RETMA System (Receiving Tubes)The first character is always a number, consisting of one to three numerals, and almost always represents the heater voltage to the nearest whole number. These numerals are followed by one or two letters assigned to the devices in some sort of semi-chronological order of development and introduction to the marketplace, and then another single numeral which represents the number of active elements in the tube (including any internal screen plus the heater in indirectly heated tubes - electrodes connected together internally count as one). Sometimes a string of up to three Roman letters can be suffixed to the overall number; these generally delineate various revisions and improvements to the original model or different bulb shapes. "RETMA" is the acronym for the Radio Electronic Television Manufacturers Association, originally the RMA, later RTMA, then EIA (Electronic Industries Association). For a more detailed description of this numbering system see RETMA tube designation. For a detailed description of the RMA numbering system used for transmitting and special-purpose tubes, see RMA tube designation West European SystemThis system is very descriptive of what type of device, (triode, diode, pentode etc.), it is applied to, but it is not as easy to remember specific types. 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 three numerals assigned in a semi chronological order of type development. British Military CV Naming SystemThis system prefixes a three or four digit number with the letters "CV", meaning "civilian valve" (or "common valve"[1]). 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. Note the 4000 numbers identify special quality valves. U.S. Military SystemsOne 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 more domestic two or thee 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. The British also used a "VT" ["valve, transmitting": there was also a "VR" - "valve, receiving" series] system during World War II, but its devices are different to the North American devices assigned the same number. North American Radio Manufacturers Association, (RMA) SystemThis system uses a numeral and letter pair followed by two numerals. It is described in more detail under RMA tube designation. North American Numeral Only SystemsThis includes one of the oldest numbering systems, extending back to the early 1920s. A two digit numbering system starting with the UV-201A, which was considered as "type 01", extending almost continuously up into the 80s. [edit] Marconi-Osram British SystemThe Marconi-Osram designation uses a single letter followed by two numerals and sometimes by a second letter identifying different versions of a particular type. This British system is quite old, extending back to the 1920s. Other Numeral Only SystemsAt least three different four digit numeral only systems exist, possibly one each from each side of the Atlantic and a third suffixed by "60". These tend to be used for devices used in industrial or commercial equipment. Other Letter-Numeral SystemsThere 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 equipment such as medical equipment like E.C.G./E.K.G. and X-Ray machines, industrial control equipment used in factories and power plants like chart recorders and servo equipment and aircraft avionics. Early computers and telecommunication equipment also called for valves and tubes with greater quality and reliabilty than those used in domestic and consumer equipment. Heater or filament voltagesVacuum tubes fall into three main non-interchangeable categories according to their heater or filament voltage:
Heater voltages of 7,8, 9, 10, 11, 16, 17, 20 and many other voltages existed, often with the same characteristics as a 6 or 12 volt heater part, sometimes intended for use in television receivers [2] where the heaters were connected in series across the power line. [3] American designation (with European equivalents)See also RETMA tube designation, RMA tube designation "0 volt" gas-filled cold cathode tubes
1 volt heater/filament tubes
1.25 Volt filament subminiature tubesThe following tubes were used in post-WW2 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 (7.24 mm to 10.16 mm) wide, and from 1.25 to 2.00 inches (31.75 mm to 50.4 mm) in overall length. Those labeled 8 pin have round bodies and bases with 8 stiff pins arranged in a circle. Those marked FL have elliptical bodies and flat bases with long, inline “flying leads” that are soldered into the circuit. Those marked SL are similar to those marked FL, but have short inline leads that can be soldered or can be mated with a special socket. (Flying leads can be cut short to fit into inline sockets.)
1 prefix for home receiversThese tubes were made for home storage battery receivers manufactured during the early-to-mid 1930s. The numbers of the following tubes all start with 1, but these tubes all have 2.0 volt DC filaments. This numbering scheme was intended to differentiate these tubes from the tubes with 2.5 volt AC heaters listed below.
2 volt heater/filament tubes
5 volt heater/filament tubes
6 volt heater/filament tubes
“7” prefix loctal tubesThese tubes all have 6.3 volt AC/DC heaters.
12 volt heater/filament tubes
“14” prefix Loctal TubesThese tubes all have 12.6 volt AC/DC heaters
25 volt heater/filament tubes
35 volt heater/filament tubes
50 volt heater/filament tubes
117 volt heater tubesAll 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.
Shielded tubes for Majestic radiosIn 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.
Lettered loctal tubes used in Philco radios
European designation (with American equivalents)Most of these tubes have names which specified their heater voltage, construction, and base, for details see
"A" in the first position refers to 4v heater use.
"A" in the second position refers to signal level "Diode".
e.g. 30-39 implies an octal base, 80-89 or 180-189 implies a noval base. EA
EAA
EABEABC
EAF
EB
EBF
ECC
ECL
ECF
ECH
EF
EK
EL
EM
EN
EY
EZ
HA, HB, HD, HF, HL, HY
KT
Other Roman Letter TypesA
C
D
E
M
P
Q
R
SA power pentode similar to the beam power tetrode type 807, made by Standard Telephones and Cables Pty. Ltd.. The SY4307A differs from an 807 by being a directly heated pentode rather than an indirectly heated beam power tetrode. Both types are contained in an ST-16 bulb with an Anode Cap and 5 pin "American", UX5 base. This device is historically notable because a pair of them in parallel class C were used as the output stage in a transmitter, built in secret by Australian soldiers in Japanese occupied Portuguese Timor during World-War II in 1942. This transmitter, now reconstructed and on display at the Australian War Memorial in Canberra, was called "Winnie the War Winner".
T
U
X
Y
Z
European designation, special qualityVacuum tubes which had special qualities of some sort, very often long-life designs, particularly for computer and telecommunication 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, the E88CC a high quality version of the ECC88/6DJ8 and the E80F pentode was equivalent to the EF80. The letters "CC" iniicated 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 double 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 the 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 as well as improved oxide insulation between the heater and cathode so the cathode could be elevated a greater voltage above the heater supply. (Note that elevating the cathode a positive voltage above the average heater voltage, which in well designed equipment was supplied from a centre-tapped winding on the power transformer, with the tap earthed to zero volts, was less detrimental to the oxide insulation between the heater and cathode than depressing the cathode a negative voltage below zero volts due to pyrometallurgical electrolytic chemical reactions where the oxide touched the nickel cathode forming conductive aluminium tungstate and developing a heater-cathode short-circuit.) Better, often dual, getters and more rigid support of the grid wires were implemented to maintain a better vacuum, reduce microphonics and improve vibration and shock resistance. The mica spacers use in "SQ" and "PQ" types did not possess any 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 had a constricted section of bulb to firmly hold specially shaped flakeless mica spacers, particularly the E80F, E88CC and E90CC.[7] Numbered tubesTubes used in 1920s and 1930s radio receivers
Other numbered tubes2
4
8 and higher
Russian tubesMain article: Russian tube designations
Classes of vacuum tube
Classes of electronic tube containing gas or vapourReferences
External links
 List of vacuum tubes |