A detector of radio waves used in very early radio receivers(noun)
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Use "coherer" in a sentence
"The name coherer comes from the first practical instrument made for this purpose."
"The tube of filings through which the electric current is made to pass in wireless telegraphy is called a coherer signifying that the filings cohere or cling together under the influence of the electric waves."
"The instrument for this purpose is called a coherer, in which small particles cohere through the action of the electric waves, and are caused to fall apart mechanically, during the electrical impulses."