Hughes microphones and apparatus, c 1880s. From left to right: an experimental microphone consisting of a carbon pencil resting in a carbon cup; a rectangular cell; a clockwork driven spark transmitter (the first radio transmitter in the world); a variable resistor; two experimental microphones consisting of needles suspended in contact with blocks of gas carbon; a microphone detector (the first radio receiver in the world); another cell; and a Bell telephone receiver. David Hughes (1831-1900) was a Welsh inventor who discovered that loose electrical contacts are very sensitive to vibrations, including sound. By placing three nails on a wooden board, Hughes created a transducer more efficient than Bell's.
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