Edison Swan thermionic triode valve
1932
Marconi Wireless Telegraph thermionic triode valve
1918
Triotron thermionic triode valve
1935
Metropolitan-Vickers Cosmos thermionic triode valve
1925
Ediswan thermionic triode valve
1928
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 thermionic triode valve
1928
Marconi Osram thermionic triode valve
1923
Marconi thermionic triode valve
1923
Marconi thermionic triode valve
1923
Mullard Triode Valve MZ05-60
Marconi Osram thermionic triode valve
1935
Metropolitan-Vickers Cosmos thermionic triode valve
1923
British Thomson-Houston thermionic triode valve
1924
Thermionic triode valve
Cossor triode valve
circa 1930
Wade Bequest: DER triode radio valve
Moorhead thermionic triode valve
1922
Marconi Osram thermionic triode valve
1925
Marconi Osram thermionic triode valve
1927
Marconi-Osram LS3 triode, BBC-marked
Thermionic triode valve
Thermionic triode valve
Wade Bequest: DER triode radio valve
Edison Swan thermionic triode valve
1930
Metropolitan-Vickers Cosmos thermionic triode valve
1925
Fellows thermionic triode valve
1923
Marconi thermionic triode valve
1940
Marconi thermionic triode valve
1923
Marconi Osram thermionic triode valve
1923
Marconi triode valve
1930
Duval triode valve
1928
Wade Bequest: DE6b triode radio valve with green tint
Triode valve
Thermionic triode valve
KTD power amplifier
1918
Triode valve
Triode valve
Triode valve
1931
Wade Bequest: DE6 triode radio valve with blue tint
Wade Bequest: ORA triode radio valve
Thermionic triode valve
1924
Marconiphone thermionic triode valve
1942
British Thomson-Houston thermionic triode valve
1928
Cossor thermionic triode valve
1932