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.
Heater or filament ratings
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.
Tube bases and envelopes
Abbreviations used in this list ST – Shouldered tube GT – Glass tube MT – Miniature tube, such as Noval B9A or Miniature 7-pin B7G FL – Subminiature all-glass elliptical body and flat bases with long, inline "flying leads" (wire-ends) that are soldered into the circuit SL – Subminiature all-glass elliptical body and flat bases with 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.) R8 – Subminiature all-glass round body and base with 8 flying leads or stiff pins arranged in a circle
Numbering systems
North American systems
RETMA receiving tubes system
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.
The first character group is a number representing the heater voltage rounded to the nearest whole number; 0 indicates a cold-cathode tube. One or two letters assigned to the devices in order of development. A single numeral that represents the number of active elements in the tube. Suffix letters distinguish revisions or variants: A, B, C – Improved backward compatible versions E – Export version G – Glass bulb, ST-12 to ST-16 size GT – Glass bulb, T-9 size GT/G – Glass bulb, T-9 size interchangeable with G and GT types L – Loctal LM – Loctal-metal LT – Locking base M – Metal envelope MG – Metal-glass ML – Metal-Loctal S – Spray shielded W – Ruggedised, or military grade WA, WB – Improved, backward compatible military/industrial variants X – Low loss ceramic base for RF use Y – Low loss mica-filled phenolic resin ("Micanol") base for RF use Lastly, manufacturers may decide to combine two type numbers into a single name, which their one device can replace, such as: 6DX8/ECL84 (6DX8 and ECL84 being identical devices under different naming schemes) or 6BC5/6CE5 (sufficiently identical devices within the RETMA naming system) and even 3A3/3B2, or 6AC5-GT/6AC5-G (where the single type number, 6AC5-GT/6AC5-G, supersedes both the 6AC5-G and the 6AC5-GT). Often designations that differed only in their initial numerals would be identical except for heater characteristics. For examples see below
RMA professional tubes system
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.
EIA professional tubes system 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:
CK, RK – Raytheon Company ECG – Philips/Sylvania F – Federal Telephone and Radio (ITT division) GL – General Electric Corp. (not British General Electric Company) ML – Machlett Laboratories, Inc. NL – National Electronics, Inc. (Geneva, Illinois, USA) NU – National Union Electric Corp. (Orange, New Jersey, USA) PL – Philips N.V. SV – Svetlana: formerly only PJSC "Svetlana/ПАО Светлана", St. Petersburg, Russia now also a brand of New Sensor Corp., Long Island City, New York, USA, manufacturing in Saratov, Russia WL – Westinghouse Electric Corp. For examples see below.
Eimac transmitting tubes system Eitel-McCullough and other manufacturers of high power RF tubes use the following code since 1945:
An initial digit denoting the number of electrodes: 2 – Diode 3 – Triode 4 – Tetrode 5 – Pentode Up to 2 letters denoting the construction type and the cooling method: R or a dash ("-") – Glass envelope, radiation cooling C – Ceramic envelope K – (Reflex-)Klystron P – Primarily for pulse applications L – External anode, liquid convection cooling N – External anode, natural convection air cooling S – External anode, conduction cooling V – Vapor cooled (anode is immersed in boiling water, and the steam is collected, condensed and recycled) W – Water cooled (water is pumped through an outer metal jacket thermically connected to the anode) X – Forced-air cooled (air is blown through cooling fins thermally connected to the anode) A number to indicate the maximum anode dissipation in watts. This can be exceeded for a short time, as long as the average is not exceeded over the anode's thermal time constant (typically 0.1 sec). In Class-C applications, the amplifier output power delivered to the load may be higher than the device dissipation One or more manufacturer-proprietary letters denoting the construction variant An optional digit denoting the gain group: 1 – ≤10 2 – 11...20 3 – 21...30 4 – 31...50 5 – 51...100 6 – 101...200 7 – 201...500 8 – 501...1000 Optionally a slash "/" followed by the RMA or EIA equivalent. Examples:
3CW5000A3 – 5 kW Ceramic triode, water cooled, variant 'A', gain group 3 3CX100A5 – 100 W Ceramic UHF triode, forced-air cooled, variant 'A', gain group 5; often used by radio amateurs for 23cm-band microwave amplifiers. 3CX1500A7 (8877) – 1.5 kW Ceramic triode, forced air cooled, variant 'A', gain group 7 3CX2500A3 – 2.5 kW Ceramic triode, forced air cooled, variant 'A', gain group 3 4-65A (8165) – 65 W Glass beam tetrode 4-125A (4D21, 6155) – 125 W Glass beam tetrode 4-250A (5D22, 6156) – 110 MHz, 250 W Glass beam tetrode 4-400A – 400 W Glass beam tetrode 4-1000A (8166) – 1 kW Glass beam tetrode popular in broadcast and amateur transmitters. 4CX250B – 250 W Ceramic tetrode, forced-air cooled, version 'B', favored by radio amateurs as a final amplifier. 4CX250BC – 250 W Ceramic tetrode, forced-air cooled, version 'BC' 4CX35000 – Ceramic tetrode used in numerous 50-kW broadcast transmitters, forced-air cooled, often in a Doherty configuration as in the Continental Electronics 317C series. 5-125B/4E27A – 75 MHz, 125 W Glass power pentode 5-500A – 500 W Glass radial-beam pentode 5CX1500A – 110 MHz, 1.5 kW Ceramic radial-beam pentode, forced air cooled 5CX3000A – 150 MHz, 4.0 kW Ceramic radial-beam pentode, forced air cooled 5K70SH – 30 kW S-band Klystron
West European systems
Mullard–Philips system
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(fr, nl) (be, Adzam brand), Mullard (uk), Philips (nl, Miniwatt brand), RCA (us), RFT(de, sv) (de), Siemens (de), Telefunken (de), Tesla (cz), Toshiba (ja), Tungsram (hu), Unitra (pl, Dolam, Polam and Telam brands) and Valvo(de, it) (de).
Standard tubes 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.
First letter: heater/filament type Heater ratings for series-string, AC/DC tubes are given in milliamperes; heater ratings for parallel-string tubes are given in volts A – 4 V heater for 2-cell lead-acid batteries and for AC mains transformers B – 180 mA DC series heater C – 200 mA AC/DC series heater D – 1.4 V DC filament for Leclanché cells, later low-voltage/low power filament/heater: 0.625 V DC directly heated for NiCd battery, series-heated two-tube designs such as hearing aids. If either filament breaks, further draining of all batteries stops Wide range 0.9 V to 1.55 V DC directly heated for dry cells 1.25 V DC directly heated for NiCd batteries 1.25 V or 1.4 V AC from a separate heater winding on CRT horizontal-output transformers, in half-indirectly heated EHT rectifiers E – 6.3 V parallel heater; for 3-cell lead-acid vehicle crank batteries (mobile equipment) and for AC mains or horizontal-output transformers F – 12.6 V DC parallel heater for 6-cell lead-acid vehicle crank batteries G – Various heaters between 2.5 and 5.0 V AC (except 4 V) from a separate heater winding on a mains or horizontal-output transformer for the anode voltage rectifier H – 150 mA AC/DC series heater Until at least 1938: 4 V battery (as opposed to A for "4 V AC"; no known examples assigned) I – 20 V heater K – 2.0 V filament for 1-cell lead-acid batteries, later for AC transformers L – 450 mA AC/DC series heater; was shifted here from Y M – 1.9 V, directly heated N – 12.6 V, indirectly heated O – Cold cathode by 1955 this also included semiconductors as these had no heater Philips sold a family of 150mA series heater tubes under this letter in South America P – 300 mA AC/DC series heater Q – 2.4 V, indirectly heated R – Not assigned to avoid any confusion with the older Telefunken "R" system S – 1.9 V, indirectly heated T – Custom heater U – 100 mA AC/DC series heater V – 50 mA AC/DC series heater X – 600 mA AC/DC series heater Y – 450 mA AC/DC series heater, shifted to L to avoid conflicts with the professional tubes system Z – Cold cathode tube; was shifted here from O after the advent of semiconductors Second and subsequent letters: system type <none> or R – Resistive element (ballast tube, barretter, photoresistor) A – Small signal diode B – Dual small signal diode C – Small signal triode D – Power output triode E – Small signal tetrode F – Small signal pentode H – Mixer hexode, special purpose heptode K – Mixer heptode or octode L – Power output, beam tetrode or pentode M – Optical tuning/level indicator N – Noble-gas Thyratron P – Secondary emission tube – mostly used as third letter Q – Nonode S – Special tube (German: Sonderröhre) T – Beam deflection tube, or misc. W – Gas-filled half-wave rectifier X – Gas-filled full-wave rectifier Y – Vacuum half-wave rectifier (power diode) Z – Vacuum full-wave rectifier (dual power diode with common cathode) Following digits: model number and base type For signal pentodes, an odd model number most often identified a variable-mu (remote-cutoff) tube, whereas an even number identified a 'high slope' (sharp-cutoff) tube For power pentodes and triode-pentode combinations, even numbers usually indicate linear (audio power amplifier) devices while odd numbers were more suited to video signals or situations where more distortion could be tolerated. 1–9 – Pinch-type construction tubes, mostly P8A side-contact 8-pin bases (P base) or V5A side-contact 5-pin (V base) and various other European pre-octal designs 10–19 – Y8A 8-pin steel tube base, aka "German metal octal" 20–29 – Loctal B8G; some octal; some 8-way side contact (exceptions are DAC21, DBC21, DCH21, DF21, DF22, DL21, DLL21, DM21 which have octal bases) 30–39 – International Octal (IEC 67-I-5a), also known as IO or K8A 40–49 – Rimlok (Rimlock) B8A All-glass miniature tubes 41w – Battery-heated cup tube (German: Pressnapfröhre) 50–59 – "Special construction types fitted with bases applicable to design features used"; mostly locking bases: "9-pin Loctal" (B9G) or 8-pin Loctal (B8G); but also used for Octal and others (3-pin glass; Disk-seal incl. Lighthouse tubes; German 10-pin with spigot; min. 4-pin; B26A; Magnoval B9D) 60–69 – Pencil tubes – sub-miniature all-glass tubes, wire-ended (inline fly-leads in place of pins) —Before the 1950s: 60–64 – All-glass tubes fitted with 9-pin Loctal (B9G) bases 70–79 – Pencil tubes with circular pins or fly-leads —Before the 1950s: 70–79 – 8-pin Loctal (Lorenz) 80–89 – Noval B9A (9-pin; IEC 67-I-12a) 90–99 – "Button" B7G (miniature 7-pin; IEC 67-I-10a) 100–109 – B7G; Wehrmacht base; German PTT base 110–119 – Y8A 8-pin steel tube base; Rimlock B8A 130–139 – Octal 150–159 – German 10-pin with spigot; 10-pin glass with one big pin; Octal 160–169 – Inline wire-ended Pencil tubes; Y8A 8-pin steel tube base 170–179 – RFT 8-pin; RFT 11-pin all-glass gnome tube with one offset pin 180–189 – Noval B9A 190–199 – Miniature 7-pin B7G 200–209 – Decal B10B 230–239 – Octal 270–279 – RFT 11-pin all glass with one offset pin 280–289 – Noval B9A 300–399 – Octal 400–499 – Rimlock B8A 500–529 – Magnoval B9D 600–699 – Inline wire-ended Pencil tubes 700–799 – Circular wire-ended Pencil tubes 800–899 – Noval B9A 900–999 – Miniature 7-pin B7G —Special quality:
1000– Round wire-ended; special Nuvistor base 2000– Decal B10B 3000– Octal 5000– Magnoval B9D 8000– Noval B9A For examples see below
Special quality tubes 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:
1 – Miscellaneous 2 – 10-pin Decal base (JEDEC E10-61) 3 – Octal base (IEC 67-1-5a) 5 – Magnoval base (JEDEC E9-23) 8 – Noval base (IEC 67-1-12a) 9 – Miniature 7-pin base (IEC 67-1-10a) For examples see below, starting at EC
"Z" Cold-cathode SQ tubes had a different function letter scheme:
A – Arc discharge tube B – Binary counter or switching tube C – Common-cathode Counter Dekatron that makes only carry/borrow cathodes separately available for cascading E – Electrometer tube G – Gating tube M – Optical indicator S – Separate-cathode Counter/Selector Dekatron that makes all cathodes available on individual pins for displaying, divide-by-n counter/timer/prescalers, etc. T – Relay triode, a low-power triode thyratron, one starter electrode, may need illumination for proper operation if not radioactively primed U – Low-power tetrode thyratron, may mean: Trigger tetrode, one starter electrode and a primer (keep-alive) electrode for ion availability to keep the ignition voltage constant, for analog RC timers, voltage triggers, etc. Relay tetrode, two starter electrodes to make counters bidirectional or resettable W – Trigger pentode, two starter electrodes and a primer electrode X – Shielded Trigger pentode, two starter electrodes, a primer electrode and a conductive coating of the glass envelope inside connected to a separate pin For examples, see below under Z
Professional tubes In use since at least 1961, this system was maintained by Pro Electron after their establishment in 1966. Both letters together indicate the type:
X – High vacuum electro-optical devices XA – Phototube XG – Miscellaneous XM – Character generating cathode ray tube XP – Photomultiplier XQ – Camera tube XR – Monoscope XS – Cathode ray charge storage tube XT – Memory display tube XV – Infrared detector XW – Infrared imaging device XX – Image intensifier or image converter Y – Vacuum tubes YA – Diode YD – Transmitting or industrial, single or dual triode YG – Electrometer tube, vacuum gauge YH – Traveling-wave tube YJ – Magnetron YK – Klystron YL – Transmitting or industrial, single or dual tetrode or pentode YN – Backward-wave oscillator YP – Electron multiplier YR – Crossed-field amplifier YT – Pulse modulator tube YY – High vacuum rectifier Z – Gas-filled tubes not employing photosensitive materials ZA – Cold cathode indicator tube ZB – Microwave switching tube (TR/ATR cells, etc.) ZC – Trigger tube ZD – Surge arrester ZE – Glow modulator tube, a linear light source for rotating-drum FAX receivers, film soundtrack recording, etc. ZF – Flash tube ZL – Gas laser ZM – Cold cathode character display tube or counter display tube ZP – Radiation counter tube (Geiger-Müller counter tube or proportional counter tube) ZQ – Mixed analogue and digital display ZR – Plasma display panel ZS – Bar graph ZT – Thyratron ZX – Ignitron ZY – Mercury-vapor rectifier ZZ – Voltage stabilizer or corona discharge tube Then follows a 4-digit sequentially assigned number. Optional suffixes for camera tubes: Version letter:
B – Blue G – Green L – Luminance R – Red T – Reticule X – Medical X-ray Letter for variants derived by selection:
D – High resolution M – Blemish standard For examples see below
Transmitting tubes The first letter (or letter pair, in the case of a dual-system device) indicates the general type:
B – Backward-wave amplifier D – Rectifier, including grid-controlled types J – Magnetron K – Klystron L – Traveling-wave tube M – Triode (AF amplifier or modulator) P – Pentode Q – Tetrode R – Rectifier, including grid-controlled types T – Triode (RF, oscillator) X – Large thyratron (including all hydrogen thyratrons and high-current types) 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.
Philips vacuum devices: A Microwave tubes: Output power <1W Other tubes: Directly heated tungsten filament B Microwave tubes: Output power ≥1W Other tubes: Directly heated thoriated tungsten filament C – Directly heated oxide-coated filament E – Indirectly heated oxide-coated cathode Mullard vacuum devices: D – Disk-seal construction N – External magnet required (magnetrons) P – Packaged construction (magnetrons) S – Reflex klystron T – Multiple resonator (klystrons) V – Indirectly heated oxide-coated cathode X – Directly heated tungsten filament Y – Directly heated thoriated tungsten filament Z – Directly heated oxide-coated filament (except mercury-vapor rectifiers) Gas-filled devices: G – Mercury-vapor filling, directly heated oxide-coated filament H – Hydrogen filling R – Rare-gas filling X – Xenon filling The next letter indicates the cooling method or other significant characteristic:
H – Helix or other integral cooler L – Forced-air cooling Q – Shield-grid (tetrode) thyratron (thyratrons only) S – Silica envelope, to allow for a glowing anode T – Tunable microwave device W – Water cooling The following group of digits indicate:
Microwave tubes: Frequency in GHz Rectifying tubes: DC output voltage in kV Thyratrons: Peak inverse voltage in kV Transmitting tubes: Maximum anode voltage in kV The following group of digits indicate the power:
Backward-wave amplifier or Traveling-wave tube: Output power 2nd letter: A – in mW 2nd letter: B – in W Klystrons: Output power in W Reflex Klystrons: Output power in mW Magnetrons: Pulse output power in kW Continuously transmitting tubes: Maximum anode dissipation in W or kW in Class-C amplifier telegraphy Pulsed transmitting tubes: Maximum peak anode current in A (number preceded by "P") Rectifiers: Maximum average anode current in mA Thyratrons: Maximum average anode current: Less than 3 digits: in mA 3 or more digits: 1st digit: =0 – in mA 1st digit: >0 – in A An optional following letter indicates the base or connection method:
B – Cables E – Medium 7-pin U7A base ED – Edison screw E27 lamp base EG – Goliath E40 lamp base F – 12.6V Heater G – Medium 4-pin UX4 base GB – Jumbo 4-pin base GS – Superjumbo 4-pin base N – Medium 5-pin UY5 base P – Side-contact 8-pin base For examples see below
Phototubes and photomultipliers The first digit indicates the tube base:
2 – Loctal 8-pin base 3 – Octal base 5, 6 – Special base or flying leads 8 – Noval base 9 – Miniature 7-pin base The second digit is a sequentially assigned number. The following letter indicates the photocathode type:
A – Caesium-activated antimony cathode. Used for reflective-mode photocathodes. Response range from ultraviolet to visible. Widely used. C – Caesium-on-oxidated-silver cathode, also called S1. Transmission-mode, sensitive from 300...1200 nm. High dark current; used mainly in near-infrared, with the photocathode cooled. T – Trialkali sodium-potassium-antimony-caesium cathode, wide spectral response from ultraviolet to near-infrared; special cathode processing can extend range to 930 nm. Used in broadband spectrophotometers. U – Caesium-antimony cathode with a quartz window The following letter indicates the filling:
G – Gas-filled V – High-vacuum A following letter P indicates a photomultiplier. Examples:
50AVP – 11-stage photomultiplier for scintillation counters, duodecal base 51UVP – 11-stage photomultiplier, duodecal base 52AVP/XP1180 – 10-stage photomultiplier, 13-pin base 53AVP, 153AVP – 10-stage photomultiplier, diheptal 14-pin base 53UVP – 11-stage photomultiplier, diheptal 14-pin base 54AVP – 11-stage photomultiplier, diheptal 14-pin base 55AVP – 15-stage photomultiplier, bidecal 20-pin base 56AVP – 14-stage photomultiplier, bidecal 20-pin base 56UVP – 14-stage photomultiplier, duodecal base 57AVP – 11-stage photomultiplier, bidecal 20-pin base 58AVP – 14-stage photomultiplier, bidecal 20-pin base 150AVP – 10-stage photomultiplier, bidecal 20-pin base 150CVP – 10-stage photomultiplier, bidecal 20-pin base 57CV – Photometric cell 58CG – Gas-filled phototube, Red/IR sensitive, all-glass wire-ended 58CV – Vacuum phototube, Red/IR sensitive, all-glass wire-ended 90AG – Gas-filled phototube, daylight/blue sensitive, miniature 7-pin base 90AV – Vacuum phototube, blue sensitive, miniature 7-pin base 90CG – Gas-filled phototube, Red/IR sensitive, miniature 7-pin base 90CV – Vacuum phototube, Red/IR sensitive, miniature 7-pin base 92AG – Gas-filled phototube, blue sensitive, miniature 7-pin base 92AV – Vacuum phototube, blue sensitive, miniature 7-pin base 61SV/7634 – PbS infrared (300...3500 nm) photoresistor, 2-pin all-glass wire-ended
Voltage stabilizers The first number indicates the burning voltage The following letter indicates the current range:
A – max. 10mA B – max. 22mA C – max. 60mA D – max. 100mA E – max. 200mA The following digit is a sequentially assigned number. An optional, following letter indicates the base:
E – Edison screw lamp base K – Octal base P – Side-contact 8-pin base Examples:
75B1 – Voltage reference tube, miniature 7-pin base 75C1 – Voltage reference tube, miniature 7-pin base 83A1 – Voltage reference tube, miniature 7-pin base 85A1/0E3 – Voltage reference tube, B8G Loctal base 85A2/0G3 – Voltage reference tube, miniature 7-pin base 90C1 – Voltage reference tube, miniature 7-pin base 95A1 – Voltage reference tube, miniature 7-pin base 100E1 – Voltage reference tube, A4A European 4-pin Base 108C1/0B2 – Voltage reference tube, miniature 7-pin base 150A1 – Voltage reference tube, P8A side-contact 8 base 150B2 – Voltage reference tube, miniature 7-pin base 150B3 – Voltage reference tube, miniature 7-pin base 150C1 – Voltage reference tube, P8A side-contact 8 base 150C2/0A2 – Voltage reference tube, miniature 7-pin base 150C4 – Voltage reference tube, miniature 7-pin base
Compagnie des Lampes (1888, "Métal") system 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
A – 1 V B – 2 V D – 4 V E – 5 V F – 6 V G – 7 V Second letter: Heater or filament current
W – ≥200 mA X – 150 mA Y – 100...140 mA Z – <100 mA Next number: Gain Next number: Internal resistance in kΩ Examples:
BW604 – Métal secteur indirectly AC-heated AF power triode BW1010 – Métal secteur indirectly AC-heated AF triode
EdiSwan ("British Mazda") systems
Note: EdiSwan also used the Mullard–Philips scheme.
Signal tubes First number: Heater or filament rating
0 – Misc. higher voltages 1 – 1.4 V 6 – 6.3 V 10 – 100 mA 20 – 200 mA 30 – 300 mA Following letter or letter sequence: Type
C – Frequency changer with special oscillator section D – Signal diode(s) F – Tetrode or pentode FD – Tetrode or pentode and diode(s) FL – Tetrode or pentode, and triode K – Small gas triode or tetrode thyratron L – Single or dual triode, including oscillator triode LD – Triode and diode(s) M – Optical tuning/level indicator P – Power tetrode or pentode PL – Power tetrode or pentode, and signal triode Final number: Sequentially assigned number
Power tubes Letter(s): Type
U – High-vacuum half-wave rectifier UU – High-vacuum full-wave rectifier Number: Sequentially assigned number Examples: Note: "AC/"-series receiver tubes are listed under other letter tubes - AC/
6C10 (6CU7/ECH42) – Triode/hexode frequency converter, Rimlock base 6F22 (6267/EF86) – Low-noise A.F. pentode, noval base 6F33 – Shielded pentode, Miniature 7-pin base 6L12 (6AQ8/ECC85) – Dual triode, noval base 6L19 – Dual triode, Rimlock base 6M2 (6CD7/EM34) – Dual-sensitivity tuning indicator, octal base 6P15 (6BQ5/EL84) – Power pentode, noval base 10PL12 (50BM8/UCL82) – Triode/power pentode, noval base U381 (38A3/UY85) – Half-wave rectifier, noval base UU9 (6BT4/EZ40) – Full-wave rectifier, rimlock base
EEV system This system consists of one or more letters followed by a sequentially assigned number
A – High vacuum rectifier AFX – Rare-gas filled triode thyratron AH – Mercury-vapor rectifier AX – Xenon filled rectifier B – Radiation-cooled triode BD – Mercury vapor rectifier BK – Ignitron BM – Magnetron BR – Forced air cooled triode BS – TR (Transmit/receive) cell, TB cell, Solid-state microwave device BT – Mercury vapor or xenon filled thyratron BW – Water cooled triode BY – Vapor cooled triode C – Radiation-cooled tetrode CR – Forced air cooled tetrode CW – Water cooled tetrode CX – Hydrogen tetrode thyratron E – Storage tube FX – Hydrogen triode thyratron GX – Spark gap K – Klystron M – Magnetron NFT – Nernst filament, a source of mid-infrared radiation P – Video camera tube QS – Voltage-regulator tube QT – Cold-cathode trigger tube T – CRT U – Vacuum capacitor XL – Glow modulator tube, flash tube, gas laser Examples:
B142 – 400 W RF power triode up to 50 MHz similar to 833A B1109 = 3C24 – 25 W VHF power triode up to 60 MHz B1135 = 5867 = CV1350 – VHF power triode up to 100 MHz B1152 – 500W RF power triode up to 50 MHz QT1257 – Touch button tube, an illuminated capacitance touch switch; a cold-cathode DC relay tube, external (capacitive) starter activated by touching; then the cathode glow is visible. 6-pin octal base XL601, XL602, XL603, XL627, XL628, XL631 and XL632 – Cold-cathode, linear light source (glow modulator tube), gas diode with a blue-violet glow, modulation up to 1 MHz, 2-pin Octal base, for rotating-drum FAX receivers, etc.
ETL computing tubes system 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:
An initial letter denoting the filling: G – Noble gas-filled V – Vacuum One letter denoting the type: C – Common-cathode Counter Dekatron that makes only carry/borrow cathodes separately available for cascading D – Diode, voltage reference, etc. R – Register (Readout) – Digital indicator S – Trochotron or Separate-cathode Counter/Selector Dekatron that makes all cathodes available on individual pins for displaying, divide-by-n counter/timer/prescalers, etc. TE – Trigger tetrode, one starter electrode and a keep-alive (primer) electrode for ion availability TR – Trigger triode, one starter electrode only A digit group: Dekatrons: Stage count Digital indicators: Display cathode count Diodes, voltage references: Nominal voltage Trigger tubes: Ignition voltage An optional digit group after a slash: Pin count One letter denoting the type: A – Plastic base B – Plastic base C – Plastic base D – Plastic base E – Plastic base G – 26-pin B26A base H – 27-pin B27A base M – B7G base P – B7G base Q – B7G base W – Wire-ends X – Wire-ends Y – Wire-ends Examples:
GC10/2P – Neon-filled, 1 kHz Miniature decade Counter Dekatron, a gas-filled, bidirecional decade counter tube GC10A – Helium-filled, decade Counter Dekatron GC10B – Neon-filled, 4 kHz Long life, decade Counter Dekatron GC10/4B – 4 kHz Decade Computing Counter Dekatron with carry/borrow cathodes "0" and "9" and intermediate cathodes "3" and "5" wired to separate pins GC10D – 20 kHz Decade Counter Dekatron, for single-pulse operation GC12/4B – 4 kHz Duodecimal Counter Dekatron with carry/borrow cathodes 11 and 12 and intermediate cathodes 6 and 8 wired to separate pins GCA10G – 10 kHz max. Decade Counter Dekatron with routing guides and aux anodes to directly drive Nixie tubes, B27A base without the inner pin ring GD2V – 2 kV, 16 J discharge tube, all-glass studded GD75P – 75 V Voltage reference, miniature 7-pin base GD90M – 90 V Voltage reference, miniature 7-pin base GD340X – 345 V/3...200 μA Corona voltage reference, all-glass wire-ended GD350X, GD350Y – 350 V/3...200 μA Corona voltage reference, all-glass wire-ended GD550W – 550 V, 1.5 J Discharge tube, e.g. for power relaxation oscillators, all-glass wire-ended GDT120M – 9 mA Gas-filled cold-cathode DC triode, one starter and a separate glow diode acting as an optical primer, miniature 7-pin base GR2G – + - Neon-filled digital indicator tube, 18 x 18 mm characters, side-viewing GR2H – + - Neon-filled digital indicator tube, 20 x 20 mm characters, top-viewing GR4G – 1⁄4 1⁄2 3⁄4 1 Neon-filled digital indicator tube, 18 x 30 mm characters, side-viewing GR7M – + - V A Ω % ~ Neon-filled digital indicator tube, 15.5 mm character height, top-viewing GR10A – Gas-filled digital indicator tube with a dekatron-type readout GR10G – 0 1 2 3 4 5 6 7 8 9 Neon-filled digital indicator tube, 16.86 x 30 mm characters, side-viewing GR10H – 0 1 2 3 4 5 6 7 8 9 Neon-filled digital indicator tube, 12 x 19 mm characters, top-viewing GR10J – 0 1 2 3 4 5 6 7 8 9 Neon-filled digital indicator tube, 16.86 x 30 mm characters, side-viewing GR10K – 0 1 2 3 4 5 6 7 8 9 Neon-filled digital indicator tube, 12 x 19 mm characters, top-viewing GR10M – 0 1 2 3 4 5 6 7 8 9 Neon-filled digital indicator tube, 10 x 15.5 mm characters, top-viewing GR10W – 0 1 2 3 4 5 6 7 8 9 Neon-filled digital indicator tube, 8.42 x 15 mm characters, side-viewing, all-glass wire-ended GR12G – A B C D E F G H I J K L Neon-filled digital indicator tube, 16 x 30 mm characters, side-viewing GR12H – E L M N P R S T U V W X Neon-filled digital indicator tube, 16 x 30 mm characters, side-viewing Note: More Nixie tubes under standard - ZM and professional - ZM
GS10C – 4 kHz max. Decade Counter/Selector Dekatron, top-viewing, duodecal base GS10D – Hydrogen-filled, 20 kHz max. Decade Counter/Selector Dekatron, duodecal base GS10H – 4 kHz max. Decade Counter/Selector Dekatron with routing guides, B17A base GS12C – 4 kHz max. Duodecimal Counter/Selector Dekatron, with solder lugs GS12D – Neon-filled, 4 kHz max. duodecimal Counter/Selector Dekatron, duodecal base with two additional wire-ends for the guide electrodes GSA10G – 10 kHz max. Decade Counter/Selector Dekatron with routing guides and aux anodes to directly drive Nixie tubes, B27A base GTE120Y – 5 mA Subminiature DC trigger tetrode, one starter and one primer, all-glass wire-ended GTE130T – 8 mApeak DC trigger tetrode, one starter and one primer, close tolerance, low aging, quadrant I operation only, noval base GTE175M – 3.5 mAavg, 50 mApeak DC Trigger tetrode, one starter and one primer, miniature 7-pin base, for Dekatron coupling circuits GTR120W – 9 mA Subminiature DC trigger triode, 3-pin all-glass wire-ended, for computer applications GTR75M – 75 V Voltage reference, Miniature 7-pin GTR95M/S – 95 V Voltage reference, Miniature 7-pin GTR150 – Subminiature, primed 150 V voltage reference, all-glass wire-ended VS10G – Trochotron, an electron-beam decade counter tube VS10G-M – VS10G with a magnetic shield VS10H – High-current trochotron VS10K – Low-voltage trochotron
Marconi-Osram system 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:
Note: A preceding letter M indicates a 4-volts AC indirectly heated tube A – General professional tube B – Dual triode D – Detector diode GT – Gas-filled triode GU – Gas-filled rectifier H – High-impedance signal triode KT – Kinkless Tetrode - beam power tube L – Low-impedance signal triode N – Power pentode P – Power triode up to 3 W PT – Power pentode PX – 3...25 W Power triode QP – Dual pentode S – Tetrode U – Rectifier VS – Remote-cutoff tetrode W – Remote-cutoff pentode X – Triode/hexode frequency-changer Y – Optical tuning/level indicator Z – Sharp-cutoff RF pentode The following numbers are sequentially assigned for each new device. Examples:
A1834 = 6AS7G/ECC230 = CV2523 – Dual power triode (series regulator), octal base. B309 = 12AT7/ECC81 – High-mu dual triode. Commonly used as R.F. amplifier/mixer in VHF circuits. B719 = 6AQ8/ECC85 – Dual RF triode, RF Amp & Mixer in FM receivers, noval base. D41 = V914 – Indirectly heated, Dual Detector Diode, British 5-pin base. D42 – Indirectly heated, Single Detector Diode, British 4-pin base. GU21 = AH221 = RG4-1250 – Half-wave mercury-vapor rectifier, Edison screw lamp base. H63 = 6F5 – High-mu triode, octal base. H610 – Directly heated, high-mu AF triode, British 4-pin base. KT32 (25L6, 25L6G, 25L6GT and 25W6GT) KT33 (25A6GT) KT41 KT61 (6M6G) in parallel filament circuits KT63 (6F6, 6F6G, 6F6GT) KT66 (6L6GC) KT67 – Small transmitting valve KT71 (50L6GT) KT77 – Similar to EL34, 6CA7 KT81 KT88 = 6550A = CV5220 (12E13, 7D11) – AF beam power tube, two tubes are capable of providing 100W output, Class-AB1, octal base L63 = 6J5 – Low-mu triode, octal base. L610 – Directly heated, Low-mu RF triode, British 4-pin base. MT7A, MT7B – Large radiation-cooled transmitting triodes used in the 1920s and 1930s. MU14 = UU5 = IW4-500 – Indirectly heated full-wave rectifier, British 4-pin base. N77 = 6AM5/EL91 – Power pentode, 7-pin miniature base. P425 = PM254 – Power triode with a 4 V/200 mA battery heater and a British 4-pin base P610 – Directly heated, AF power triode, British 4-pin base. P625 – AF power triode. PX4 – AF power triode designed in the 1930s. Capable of providing about 4.5 W of audio. QP21 – Directly heated, dual AF (push-pull) power pentode, British 7-pin base. QP240 – Directly heated, dual AF (push-pull) power pentode, British 9-pin base. S610 – Directly heated, Sharp-cutoff RF tetrode, British 4-pin base. U52 = 5U4G = 5AS4A/5U4GB – Full-wave rectifier, octal base. VS24 – Directly heated, Remote-cutoff RF tetrode, British 4-pin base. W727 = 6BA6/EF93 = 5749 – Remote-cutoff RF pentode, 7-pin miniature base. X41 – Triode/hexode mixer designed to be a direct plug-in replacement for the MX40 pentagrid converte