List of vacuum tubes

Only a few types are still used today, mainly in high-power, high-frequency applications and also in boutique guitar amplifiers.

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.

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.

Eitel/McCullough and other manufacturers of high power RF tubes use the following code since 1945:[2] Examples: This system is very descriptive of what type of device (triode, diode, pentode etc.)

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.

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.

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.

"Z" Cold-cathode SQ tubes had a different function letter scheme:[11] For examples, see below under Z In use since at least 1961, this system was maintained by Pro Electron after their establishment in 1966.

The coding for vacuum devices differs between Philips (and other Continental European manufacturers) on the one hand and its Mullard subsidiary on the other.

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;[1][14] not to be confused with Compagnie des Lampes (1921, "French Mazda", see below).

Examples: Rundfunk- und Fernmelde-Technik(de, sv) was the brand of a group of telecommunications manufacturers in the German Democratic Republic.

Letter: System type: Number: Examples:[23] Vacuum tubes produced in the former Soviet Union and in present-day Russia are designated in Cyrillic.

[24] 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.

Examples:[26] 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.

An optional fifth element consists of a dash followed by one or more characters to designate special characteristics of the tube.

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.

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.

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.

There are quite a number of these systems from different geographical realms, such as those used on devices from contemporary Russian and Chinese production.

Some letter prefixes are manufacturer's codes: For examples, see below Some designations are derived from the behavior of devices considered to be exceptional.

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: [139] Used with AC, DC or home-based storage battery power supplies (1927–31) Used in 1920s home radios.

Used in 1920s home radios powered by dry cells (filaments) and storage batteries (B-plus voltage).

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.

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.