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In Europe, the principal method of numbering vacuum tubes ("thermionic valves") was the nomenclature used by the Philips company and its subsidiaries Mullard in the UK, Valvo in Germany, and Dario in France, from 1934. This system allocated meaningful codes to tubes based on their function. This European common code system became the starting point for the Pro Electron naming scheme for active devices (including tubes and transistors). ==Nomenclature systems== The system allowed for cross-referencing with the American RETMA tube designation, the Marconi-Osram tube designation, and with military numbering systems such as civilian valve (CV) numbering in the United Kingdom and the Joint Army–Navy (JAN) tube designation in the US. European tube manufacturers agreed on the system, but in the UK, MOV (Marconi-Osram Valve), STC/Brimar and Mazda/Ediswan maintained their own systems. Most MOV tubes were cross-licensed copies of RCA types, with a British designation. For example an MOV X63 valve was the same as an RCA 6A8 tube. Brimar, which stood for "British Manufactured American Radio" (valves), used all American designations. STC/Brimar was a UK subsidiary of the American giant ITT (International Telephone and Telegraph). Special quality tubes were sometimes identified by placing the numerical part of the designation between the heater rating and the tube type. The special quality could be anything, from rugged designs for military and industrial use, through devices with exceptionally low noise and microphony, to designs primarily optimised for long life without cathode poisoning when used for switching in a digital computer (but not necessarily with exceptional qualities as an amplifier). For example an ECC81 manufactured as a special quality (SQ) tube would usually be designated 'E81CC'. The system was not universal as other special quality designation systems existed. An EF91 in its special quality version was designated 'M8083' (the 'M' meant Military) as in this case the standard EF91 was derived from the M8083 military design. Also, the SQ tube was not always designed for the same tasks or given the same Maximum Ratings (for example the E80F was more suitable for audio and electrometer applications, lacking the RF screening of the EF80, with anode and screen grid power ratings roughly half the EF80.〔http://www.r-type.org/pdfs/e80f.pdf〕 Two or more elements in a single envelope were handled by adding letters after the heater identifier, in alphabetical order, so an ECH35 is a 6.3 volt heated triode plus a hexode with an octal base; a PABC80 is a Noval 300mA series-heater combination of a single low-power diode A, a pair of diodes with common cathode B, and a triode C. There were many ECCnn(n) 6.3V dual triodes. It was the usual practice for power transformers to have a 5 volt insulated winding for rectifier filaments, and a 6.3 volt winding for all the other heaters; virtually all valves with 5V filament are rectifiers with cathode connected to heater, in practice full-wave (usable as half-wave by strapping both anodes together), e.g. GZ34. For lower-voltage lower-power requirements, rectifiers with 6.3V heaters and insulated cathodes such as the EZ80 were used, connected to the common filament supply. There is no special nomenclature for EHT rectifiers for cathode-ray tubes; the EY51 and EY86 were rated at 17kV with an average current of 350 microamps.〔(The National Valve Museum: EY51 )〕 The GY501 is another example (31kV at 1.7mA and used the rare B9D base).〔Mazda Data Book 1968〕 In practice most "xY" half-wave rectifiers are EHT types; but there are plenty of exceptions.〔(【引用サイトリンク】title= Preferred Types of Electron Tubes 1967 )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mullard–Philips tube designation」の詳細全文を読む スポンサード リンク
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