valves |
In the 1950s a 5-element system (GOST 5461-59, later 13393-76) was adopted in the (then) Soviet Union for designating receiver vacuum tubes.
This area, with nearby Brimsdown subsequently developed as a centre for the manufacture of thermionic valves, cathode ray tubes, etc. and nearby parts of Enfield became an important centre of the electronics industry for much of the 20th century.
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.