The Radio Electronics Television Manufacturers' Association was formed in 1953, as a result of mergers with other trade standards organisations, such as the RMA. It was principally responsible for the standardised nomenclature for American vacuum tubes - however the standard itself had already been in use for a long time before 1953; for example, the 6L6 was introduced in July 1936.
American-made tubes bear a RETMA designation to allow for easy cross-referencing. The RETMA tube designation does not incorporate the purpose of each tube in the designation. The Anglo-European Mullard–Philips tube designation does include tube use information in the designation.
First figure group: indicates heater/filament voltage; 0 means a cold-cathode tube.
Letter group: letter(s) indicate the serial order of assignment of the designation; combinations like AB, AC, AD, AE... were used, avoiding same-letter repetitions, after the single letters were exhausted. Wherever possible, the 12V equivalent of a 6V tube had the same letters, just 12 instead of 6.
L as a first letter often indicates a lock-in (Loktal) tube.
P as a second letter from the end indicates a CRT.
Letters U, V, W, X, Y and Z are commonly used for rectifiers
Occasionally the same letter groups were used for differing tubes but only where the last number would be different making the designation unique. For example there is a 12AV5 (beam tetrode), 12AV6 (double diode, triode) and a 12AV7 (double triode).
Second figure group is the number of useful elements (including the heater if this is separate from the cathode); in metal tubes the shell counts as one element. Internal shielding also counts, but base shielding does not. Electrodes connected together internally are counted as one element. There is an inconsistency in the way tapped heaters or filaments are counted. For example, the 12BH7 (double triode with separate cathodes) counts the center tapped heater as one useful element, whereas the 12BY7 (pentode) counts the center tapped heater as two useful elements. There are also inconsistencies in the way internal screens are treated. In the 6BX6 (pentode with g3 brought to its own pin), the screen around the assembly is not counted, whereas the 6BR7 (also a pentode with g3 brought to its own pin) has its similar screen included.[1]
In the case of a CRT, the second figure group indicates the type of phosphor the tube face was coated with.
retma, tube, designation, radio, electronics, television, manufacturers, association, formed, 1953, result, mergers, with, other, trade, standards, organisations, such, principally, responsible, standardised, nomenclature, american, vacuum, tubes, however, sta. The Radio Electronics Television Manufacturers Association was formed in 1953 as a result of mergers with other trade standards organisations such as the RMA It was principally responsible for the standardised nomenclature for American vacuum tubes however the standard itself had already been in use for a long time before 1953 for example the 6L6 was introduced in July 1936 American made tubes bear a RETMA designation to allow for easy cross referencing The RETMA tube designation does not incorporate the purpose of each tube in the designation The Anglo European Mullard Philips tube designation does include tube use information in the designation First figure group indicates heater filament voltage 0 means a cold cathode tube Letter group letter s indicate the serial order of assignment of the designation combinations like AB AC AD AE were used avoiding same letter repetitions after the single letters were exhausted Wherever possible the 12V equivalent of a 6V tube had the same letters just 12 instead of 6 L as a first letter often indicates a lock in Loktal tube P as a second letter from the end indicates a CRT Letters U V W X Y and Z are commonly used for rectifiersOccasionally the same letter groups were used for differing tubes but only where the last number would be different making the designation unique For example there is a 12AV5 beam tetrode 12AV6 double diode triode and a 12AV7 double triode Second figure group is the number of useful elements including the heater if this is separate from the cathode in metal tubes the shell counts as one element Internal shielding also counts but base shielding does not Electrodes connected together internally are counted as one element There is an inconsistency in the way tapped heaters or filaments are counted For example the 12BH7 double triode with separate cathodes counts the center tapped heater as one useful element whereas the 12BY7 pentode counts the center tapped heater as two useful elements There are also inconsistencies in the way internal screens are treated In the 6BX6 pentode with g3 brought to its own pin the screen around the assembly is not counted whereas the 6BR7 also a pentode with g3 brought to its own pin has its similar screen included 1 In the case of a CRT the second figure group indicates the type of phosphor the tube face was coated with Optional letters A B C Improved backward compatible versions E Export version G Glass bulb Shouldered Tube ST 12 to ST 16 size GT Glass bulb T 9 size actually Glass Tubular GT G Glass bulb T 9 size interchangeable with G and GT types L Loktal LM Loktal metal LT Locking base M Metal envelope MG Metal glass ML Metal Loktal 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 2 base for RF useReferences Edit Brimar Radio Valve and Teletube Manual Edition No 7 Tube Bases and the Asbestos Hustle Receiving Tube Manual Technical Series RC 20 PDF RCA Electron Tube Division Harrison NJ USA 1960 See also EditList of vacuum tubes RMA tube designation Mullard Philips tube designation Russian tube designations Electronics portal Retrieved from https en wikipedia org w index php title RETMA tube designation amp oldid 1119012789, wikipedia, wiki, book, books, library,
