Wade Bequest: DE6b triode radio valve with green tint
Wade Bequest: DER triode radio valve
Wade Bequest: ORA triode radio valve
Wade Bequest: DER triode radio valve
Wade Bequest: DE6 triode radio valve with blue tint
Ediswan thermionic triode valve
1923
Marconi Osram thermionic triode valve
1925
Edison Swan thermionic triode valve
1932
Marconi Osram thermionic triode valve
1932
Mullard thermionic triode valve
1928
Moorhead thermionic triode valve
1922
Cossor thermionic triode valve
1932
Thermionic triode valve
1924
Marconi thermionic triode valve
1927
Metropolitan-Vickers thermionic triode valve
1925
Marconi Osram thermionic triode valve
1925
Marconi thermionic triode valve
1923
British Thomson-Houston thermionic triode valve
1928
Marconiphone thermionic triode valve
1942
KTD power amplifier
1918
Marconi thermionic triode valve
1923
Marconi Osram thermionic triode valve
1925
Marconi thermionic triode valve
1943
British Thomson-Houston thermionic triode valve
1924
Neutron thermionic triode valve
1930
Marconi thermionic triode valve
1925
Metropolitan-Vickers thermionic triode valve
1925
Marconi Osram thermionic triode valve
1927
Thermionic triode valve
circa 1920s-1930s
Marconi Osram thermionic triode valve
1923
Thermionic triode valve
Mazda triode valve
Metropolitan-Vickers Cosmos thermionic triode valve
1923
Mullard ORA triode
Marconi-Osram LS3 triode, BBC-marked
Wade Bequest: ONEVOLT ORA triode radio valve
Wade Bequest: DER triode radio valve
Marconi triode valve
1930
Metropolitan-Vickers Cosmos thermionic triode valve
1925
Marconi thermionic triode valve
1940
Ediswan thermionic triode valve
1928
Metropolitan-Vickers Cosmos thermionic triode valve
1925
Thermionic triode valve
Marconi Wireless Telegraph thermionic triode valve
1918
Thermionic triode valve
Marconi Osram thermionic triode valve
1935
Marconi Osram thermionic triode valve
1927
Marconi Osram thermionic triode valve
1923
Cossor triode valve
circa 1930