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Brass-Tipped Bone Stylus, c. 1902
Inventory Number: 82611
Number of documents: 2
Document Type: Miscellaneous Note
Document Heading: Technical Details
Text:
A coherer (or, sometimes, receiver) was an early form of detector in wireless telegraphy, based around the effect that small particles of metal filings stick together (or 'cohere') when an electric field is present. A coherer consisted of a basic electromagnetic wave detector for various wavelengths and a circuit that obtained signals from modulated radio waves. The coherer then 'decoded' these signals.
Document Type: Miscellaneous Note
Document Heading: Historical Background
Text:
A basic coherer for 'Hertzian waves' (wireless telegraphy) was first developed by a French physicist, Edouard Branly, and was later developed by Oliver Lodge and others. Marconi used a Branly-type coherer is his early wireless telegraphy experiments in Italy.
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