Spiral spring coherer, 1890-1894

Made:
1890-1894 in England
designer:
Oliver Joseph Lodge
Spiral spring coherer, c Spiral spring coherer, c

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Spiral spring coherer, c
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Spiral spring coherer, c
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Spiral spring coherer, probably made by E E Robinson, England, 1890-1894. Used by Oliver Lodge in his lecture before the Royal Institution on 1 June 1894 on ‘The work of Hertz and his successors’

Spiral spring coherer, probably made by E E Robinson, England, 1890-1894. Used by Oliver Lodge in his lecture before the Royal Institution on 1 June 1894 on ‘The work of Hertz and his successors’.

During his experiments with Hertzian waves, Oliver Lodge found it difficult to adjust the coherers (Hertzian wave detectors) to the sensitivity he required. He therefore devised this spiral wire coherer, which could be much more easily adjusted. Unlike a filings coherer, this type of detector used the imperfect contact of two dissimilar metals. It was used in a number of Lodge's experiments, including in a demonstration to members of the Royal Institution in 1894, where it was used to receive signals over a distance of about twenty yards.

Details

Category:
Radio Communication
Object Number:
1924-33
Materials:
wood (unidentified), copper (alloy) and iron
Measurements:
overall: 30 mm x 80 mm diameter, .043 kg
type:
coherer
credit:
Donated by Mr. Oliver Lodge [Grandson of Sir Oliver Lodge]