Edison Swan thermionic triode valve
1932
Marconi Wireless Telegraph thermionic triode valve
1918
Metropolitan-Vickers Cosmos thermionic triode valve
1925
Ediswan thermionic triode valve
1928
Triotron thermionic triode valve
1935
Marconi Osram triode valve
circa 1920
Marconi thermionic triode valve
1927
Marconi Osram thermionic triode valve
1925
Cleartron thermionic triode valve
1927
Neutron thermionic triode valve
1930
Thermionic triode valve
circa 1920s-1930s
Mullard Triode Valve MZ05-60
Mullard thermionic triode valve
1928
Marconi Osram thermionic triode valve
1923
Marconi thermionic triode valve
1923
Marconi thermionic triode valve
1923
Marconi Osram thermionic triode valve
1935
Thermionic triode valve
Cossor triode valve
circa 1930
Metropolitan-Vickers Cosmos thermionic triode valve
1923
Marconi Osram thermionic triode valve
1925
Moorhead thermionic triode valve
1922
Marconi Osram thermionic triode valve
1927
British Thomson-Houston thermionic triode valve
1924
Marconi-Osram LS3 triode, BBC-marked
Wade Bequest: DER triode radio valve
Edison Swan thermionic triode valve
1930
Metropolitan-Vickers Cosmos thermionic triode valve
1925
Fellows thermionic triode valve
1923
Thermionic triode valve
Marconi thermionic triode valve
1923
Marconi Osram thermionic triode valve
1923
Marconi triode valve
1930
Triode valve
Triode valve
Duval triode valve
1928
Clarion triode valve
1928/9
British Thomson-Houston triode valve
1925
Marconi triode valve
1923/4
Marconi triode valve
1930
Western Electric triode valve
1927
Marconi triode valve
1927
Edison Swan triode valve
1923
British Thomson-Houston triode valve
1925
Marconi triode valve
1923/4
Triode valve
Triode valve
1931
Wade Bequest: DE6 triode radio valve with blue tint
Wade Bequest: DE6b triode radio valve with green tint
