
One of Fleming's first thermionic diode valves, 1889
1889
1889
1830 (original); 1967 (model)
1890
1888
1892
1872 (original); 1909 (model)
1892
1889
1889
1955; 1830
circa 1890
circa 1890
circa 1890
circa 1890
before 1889
before 1889
About 1890
1893-4
1934
2000-100 BCE
1888
1890
1890
1889
1889
1705-1737
1890
1934
1930 (replica); 1834 (original)
before 1889
1801-1892 (prepared); 1946 (element replaced)
1888
4000-2001 BCE
circa 1890
circa 1890
circa 1890
circa 1890
circa 1890
1839 (original); circa 1988 (replica)
1890
1889
1668; 1924
1990-95
1610; 1923
1925; 1862
1936
1900-1933 (model); 1869 (original)
1889
1889
1890