Introduction

The thermionic valve was invented by Sir john Ambrose Fleming in 1904.

Most of the early valves were manufactured by the Marconi-Osram Valve Company located in Hammersmith which was formed in 1919 by Marconi's Wireless Telegraph Company and the General Electric Company.  The name changed to the M-O Valve Company in 1920. The GEC Wembley laboratories were responsible for research and some development on its behalf. Work on vacuum physics, metallurgy and cathode emission led to a series of successful glass envelope valves for communications and broadcasting. A major breakthrough was the cooled anode valve depending on glass-metal seals. In 1929 a vacuum laboratory was created in New Street by G.M.Wright, then managed by Dr. George Brett who continued working well into the EEV period. By 1930 world leadership had been achieved and the CAT12 transmitting valve was operating the transatlantic telephone link. The even larger CAT14 valves, each weighing about 130kg. were first made in the Laboratories. They made their debut in the BBC Droitwich long-wave transmitter in 1934 and for at least ten years were the most powerful valves in the world.

The English Electric Valve Company was created in 1947 by the English Electric Company from the Marconi valve laboratory.  It was linked with M-O Valve Company in 1969 to form GEC Electronic Tubes. Following the merger with English Electric, GEC therefore had two valve companies. EEV had its own strong research and development teams whereas M-OV relied on a large research laboratory at Wembley, although most of this was not on the main site. It was decided that the time had come for valve research as well as development to be concentrated in the two operating companies so many of the research staff moved to MOV at Hammersmith and valve research at Wembley substantially came to an end in 1971.

In 1988 the name changed to EEV Ltd, in 1999 to Marconi Applied Technologies, and in 2002, following a management buyout, to E2V Technologies, which has now become Teledyne e2v. They have picked up and are continuing work on semiconductors.

Further details can be viewed here.

Captain H.J. Round

Described below is some background to Captain Round who was responsible for much of the valve pioneering work within Marconi.

List of valve types

References

History of GEC and the Marconi Osram Valve by Fin Stewart, and is available for purchase here.  Much of the detail in this Wiki has been extracted from this document.

The National Valve Museum has details of numerous Marconi valves dating to the early 1920s.  There are also many examples of advertisements for Marconi valves on the same website.

The Radiomuseum has an extensive listing.

Marconi Valve data 1928 available here

Marconi Receiving Valves 1938 catalogue available here

Marconi Valves (date ?) available here

Marconi Valves (date ?) available here

Science Museum collection

Quartz Crystals

Quartz Crystal units

Please note that from 1960 Quartz Crystal units will no longer be included in the main catalogues.  Instead they will be included in their own catalogue RY101.

Electronic Tubes

Please note that from 1960 Electron Tubes will no longer be included in the main catalogues.  Instead they will be included in their own catalogue RY102.

Transmitting, Modulating and Power Rectifying valves

Receiving and Rectifier valves

Voltage Stabilisers

Advertisements

Adverts 1962 +

Articles 

Captain H.J. Round - an article from the October 1966 issue of Marconi Companies and Their People click here

Tetrodes in High-power MF Broadcasting Transmitters by D.F. Bowers in 1969 click here

Camera Tubes - The Choice for Monochrome by WE Turk in 1972 click here

An Improved Range of 10kW Klystrons by CN O'Loughlin in 1971 click here

Valve Instructions by the BBC in March 1961 available here

Crystals come of age available here

Still going strong - an "old valve" story  [Editors note - the two transmitters are Marconi B6042]

A relevant book, namely "Marconi" - the man who networked the world, written by Marc Raboy, has a lot of background information on the early days.

This wiki is one of a series recording the history of the Marconi Company from its formation starting from Family

Statement of intent