Double-current telegraph key, 1830-1900

Made:
1830-1900 in United Kingdom
maker:
General Post Office

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Science Museum Group Collection
© The Board of Trustees of the Science Museum

Science Museum Group Collection
© The Board of Trustees of the Science Museum

Science Museum Group Collection
© The Board of Trustees of the Science Museum

Science Museum Group Collection
© The Board of Trustees of the Science Museum

Double-current telegraph key, probably made and used by the Post Office, British, 1830-1900.

With a single-current telegraph key the position of the relay is restored to the normal position when current ceases by a magnetic bias or by a spring in tension. In other words, signal currents only flow in the line when the key is depressed. In the double-current system a current in the reverse direction is used to restore the relay to the spacing side. This example is similar to those used with the Bright's bell, or acoustic telegraph.

Details

Category:
Telecommunications
Object Number:
1953-111
Materials:
copper (alloy), metal (unknown), mother-of-pearl and wood (unidentified)
type:
telegraph
taxonomy:
  • component - object
credit:
Donated by the Institution of Electrical Engineers