Marconi coherer and Admiralty pattern decoherer, 1900-1910

Made:
1900-1910 in United Kingdom
Marconi coherer and Admiralty pattern decoherer, unknown maker Marconi coherer and Admiralty pattern decoherer, unknown maker Marconi coherer and Admiralty pattern decoherer, unknown maker Marconi coherer and Admiralty pattern decoherer, 1900-1910 (coherer) Marconi coherer and Admiralty pattern decoherer, 1900-1910 (coherer) Marconi coherer and Admiralty pattern decoherer, 1900-1910 (coherer)

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Creative Commons LicenseThis image is released under a CC BY-SA 4.0 Licence

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License this image for commercial use at Science and Society Picture Library

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Creative Commons LicenseThis image is released under a CC BY-SA 4.0 Licence

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License this image for commercial use at Science and Society Picture Library

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Marconi coherer and Admiralty pattern decoherer, unknown maker
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Marconi coherer and Admiralty pattern decoherer, unknown maker
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Marconi coherer and Admiralty pattern decoherer, unknown maker
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

Marconi coherer and Admiralty pattern decoherer, unknown maker, British, 1900-1910

The coherer was the first practical device for detecting Hertzian waves. Its most familiar form was a tube containing metal filings or turnings loosely packed between metal plugs. This presented a high resistance to current but changed to low resistance in the presence of electric waves because the filings 'cohered' or stuck together. In order to restore the high-resistance state the tube needed to be given a mechanical tap or jolt. Filings coherers were fitted with clockwork or other arrangements for driving a 'tapper' to provide continual mechanical agitation. Marconi brought the coherer to its most efficient form and it was used with receiving sets in wireless telegraphy equipment used by the Royal Navy.

Details

Category:
Radio Communication
Object Number:
1923-396
Materials:
ebonite, brass (copper, zinc alloy), plastic (unidentified), wood (unidentified), steel (metal), copper (alloy), glass and paint
Measurements:
overall: 115 mm x 100 mm x 170 mm, 1.07 kg
type:
coherer
credit:
Donated by M Child