Battery commutator for Siemens Universal galvanometer
1873-1890
Pohl commutator
1872
Pohl commutator
1872
Line commutator with 12 plugs (G N T Model 758)
Copy of Amperes commutator
1877
Double tongue commutator used by Wheatstone
1861
Bertin commutator
1886
Smith's mercurial commutator
1902
Ruhmkorff commutator
Ruhmkorff commutator
1872
Ruhmkorff commutator
Double wheel commutator
Thomson commutator motor meter
Clarke's commutator
1836-1851
BTM/Hollerith Upper Counter Commutator, c.1939
1939
Circular commutator
Hand commutator
1879
Commutator, Pohl type
1920-1943
Two Pohl commutators (see 2 stroke nos).
1872
Bertin commutator by Townson and Mercer
1897-1918