Marconi Osram thermionic triode valve
1923
Triode valve
Triode valve
Duval triode valve
1928
Mullard D0.6 triode
Wade Bequest: DE6b triode radio valve with green tint
Wade Bequest: DER triode radio valve
Moorhead thermionic triode valve
1922
Neutron thermionic triode valve
1930
Thermionic triode valve
circa 1920s-1930s
KTD power amplifier
1918
Clarion triode valve
1928/9
Wade Bequest: DER triode radio valve
Metropolitan-Vickers Cosmos thermionic triode valve
1923
Cossor thermionic triode valve
1932
Edison Swan thermionic triode valve
1932
Ediswan thermionic triode valve
1923
Marconi Osram thermionic triode valve
1932
Mullard thermionic triode valve
1928
Thermionic triode valve
1924
British Thomson-Houston triode valve
1925
Marconi Osram thermionic triode valve
1925
Marconi thermionic triode valve
1927
Metropolitan-Vickers thermionic triode valve
1925
Marconi triode valve
1923/4
Marconiphone thermionic triode valve
1942
Wade Bequest: ORA triode radio valve
Marconi triode valve
1930
British Thomson-Houston thermionic triode valve
1928
Marconi thermionic triode valve
1923
Marconi Osram thermionic triode valve
1925
Wade Bequest: DE6 triode radio valve with blue tint
Marconi Osram thermionic triode valve
1925
Marconi thermionic triode valve
1923
Western Electric triode valve
1927
Marconi triode valve
1927
British Thomson-Houston thermionic triode valve
1924
Marconi thermionic triode valve
1943
Edison Swan triode valve
1923
British Thomson-Houston triode valve
1925
Marconi triode valve
1923/4
Marconi thermionic triode valve
1925
Marconi Osram thermionic triode valve
1927
Metropolitan-Vickers thermionic triode valve
1925
Triode valve
Triode valve
1931
Siemens triode valve
1930
Loewe triode valve
1928/9
