Wheel or steel-disc coherer (thin-film detector), 1902

Made:
1902 in Beckenham
Wheel or steel-disc coherer (thin-film detector), 1902, commercial model made by Muirhead and Co for use by the Wheel or steel-disc coherer (thin-film detector), 1902, commercial model made by Muirhead and Co for use by the

Buy this image as a print 

Buy

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

License

Buy this image as a print 

Buy

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

License

Wheel or steel-disc coherer (thin-film detector), 1902, commercial model made by Muirhead and Co for use by the
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Wheel or steel-disc coherer (thin-film detector), 1902, commercial model made by Muirhead and Co for use by the
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Commercial model of a wheel or steel-disc coherer (thin-film detector), made by Muirhead and Company, 1902. For use by the Lodge-Muirhead Wireless and General Telegraphy Syndicate Ltd. Metal cover inscribed ‘Muirhead & Co / Westminster / No 15,959’, together with small fitted wooden box with space for three components (one only present)

Commercial model of a wheel or steel-disc coherer (thin-film detector), made by Muirhead and Company, 1902. For use by the Lodge-Muirhead Wireless and General Telegraphy Syndicate Ltd.

By the time that the wheel, or thin-film detector, was developed in 1902, the term 'coherer' was being applied to all types of detector, whether or not they utilised materials which 'cohered' in the presence of Hertzian waves. Edward Robinson, Oliver Lodge's assistant, was principally responsible for devising this detector. The steel disc, with a sharp edge, rotates continuously and dips into a small pool of mercury covered with a thin film of oil. When Hertzian waves are detected the disc makes contact with the mercury and as the disc rotates a fresh surface is continuously being presented to the mercury. It is therefore described as being self-cohering - that is, not requiring a series of mechanical jolts to reset it. This is the commercial form of the wheel detector, as employed on equipment made and sold by the Lodge-Muirhead Wireless and General Telegraphy Syndicate Ltd, set up by Lodge in conjunction with Alexander Muirhead, who was a successful telegraph instrument maker.

Details

Category:
Radio Communication
Object Number:
1942-39
Materials:
brass (copper, zinc alloy), plastic (unidentified), steel (metal) and wood (unidentified)
type:
coherer
taxonomy:
  • component - object
  • radio receiver
credit:
Donated by E. E. and T. H. Robinson