Thermionic triode valve
Mazda triode valve
Neutron thermionic triode valve
1930
KTD power amplifier
1918
Moorhead thermionic triode valve
1922
Thermionic triode valve
circa 1920s-1930s
Mullard D0.6 triode
Wade Bequest: DE6b triode radio valve with green tint
Wade Bequest: DER triode radio valve
Wade Bequest: DER triode radio valve
Wade Bequest: DE6 triode radio valve with blue tint
Wade Bequest: ORA triode radio valve
Thermionic triode valve
1924
Ediswan thermionic triode valve
1923
Marconi thermionic triode valve
1923
Marconi thermionic triode valve
1927
Marconi Osram thermionic triode valve
1932
Marconi Osram thermionic triode valve
1927
Metropolitan-Vickers thermionic triode valve
1925
Marconi thermionic triode valve
1943
Cossor thermionic triode valve
1932
Marconi thermionic triode valve
1923
Edison Swan thermionic triode valve
1932
British Thomson-Houston thermionic triode valve
1928
Metropolitan-Vickers Cosmos thermionic triode valve
1923
Marconi thermionic triode valve
1925
Metropolitan-Vickers thermionic triode valve
1925
Marconi Osram thermionic triode valve
1925
Marconi Osram thermionic triode valve
1925
Marconi Osram thermionic triode valve
1925
Marconiphone thermionic triode valve
1942
Mullard thermionic triode valve
1928
British Thomson-Houston thermionic triode valve
1924
Marconi Osram thermionic triode valve
1923
Marconi-Osram LS3 triode, BBC-marked
Mullard ORA triode
Amrex thermionic triode valve
circa 1923
Triotron thermionic triode valve
1935
Thermionic triode valve
Thermionic triode valve
Thermionic triode valve
Thermionic triode valve
Wade Bequest: DER triode radio valve
Wade Bequest: ONEVOLT ORA triode radio valve
Cleartron thermionic triode valve
1927
Marconi Osram thermionic triode valve
1935
Metropolitan-Vickers Cosmos thermionic triode valve
1925
Cossor triode valve
circa 1930
Marconi triode valve
1931