Den diodeensrettende effekt på blyglans blev opdaget af den tyske fysiker [[Karl Ferdinand Braun]] i 1874<ref>[http://www.computerhistory.org/semiconductor/timeline/1874-semiconductor.html computerhistory.org: 1874 – Semiconductor Point-Contact Rectifier Effect is Discovered]</ref> – og videreudviklet af radioforskerne [[Jagadish Chandra Bose]], [[Greenleaf Whittier Pickard|G. W. Pickard]]<ref name="GWP">[https://www.americanradiohistory.com/Archive-Electrical-Experimenter/EE-1919-08.pdf G. W. Pickard, "How I Invented the Crystal Detector". ''Electrical Experimenter'', vol. VII, no. 4, p. 325, Aug. 1919] Citat: "...In 1898, when my work in Radio-communication began, there was but one detector—the [[Kohærer|coherer]]...In the period 1902 to 1906, I tested many different minerals and combinations, including magnetite, pyrite, galena, molybdenite, silicon and zincite. Much development was also required on holders for these minerals...31,250 Crystal Detectors Invented. A list of the several thousand materials I have tested would make dry reading. Suffice it to say that I have found some tzvo hundred and fifty minerals and furnace products which make operative detectors, cither against metallic contacts, or in combination with other minerals. The possible combinations of these two hundred and fifty substances amounting to some 31,250, pairs, have all been tested by me, or by my assistants, and many hundred useful pairs have been found...", [https://web.archive.org/web/20220707212053/https://worldradiohistory.com/Archive-Electrical-Experimenter/EE-1919-08.pdf backup]</ref> og andre.
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