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- A Manufacturer London, United Kingdom
Telegraph Relay - Theiler & Sons, Polarized, 1861-91 Reg. No: ST 008464
- Relay used at telegraph receiving stations, particularly those operating on long connecting lines. Often signals received over long lines were too weak to operate the receiving instruments directly so the relay served as a very sensitive switch to connect a local battery to the receiving instruments.
A polarized relay incorporated a permanent magnet in its design. Because this type of relay depended completely on magnetic effects, it was faster and more sensitive in operation than a non-polarized relay which incoporated a mechanical return spring.
- Wooden base. Brass vertical cylindrical case with glass top. Brass terminals around base.
|Dimensions:||105 mm (Height), 140 mm (Width), 163 mm (Length)|
|Tagged with:||electrical relays, telegraphy|
|Themes this item is part of:||The Australian telegraph network 1854-1877, Copy of text for label for Polarised Telegraph Relay - Siemens Pattern, 1916, Telegraphy Collection, Information & Communication Collection|
|Inscriptions:||Engraved on brass plate beneath glass top:
"M. THEILER & SONS
|Manufacturer:||M. W. Theiler & Sons, London, England, Great Britain|