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Description
English: An experimental negative resistance oscillator using a zincite point-contact semiconductor junction, invented in 1923 by Oleg Losev. This technology, discovered by William Henry Eccles and G. W. Pickard around 1908 but independently discovered and developed by Russian radio researcher Oleg Losev in 1923 and dubbed "Crystodyne" by Hugo Gernsback, was the first solid-state oscillator and the first device using negative resistance and amplification in semiconductors. Losev used this technology to build the first semiconductor amplifiers, regenerative radio receivers, and radio transmitters, 25 years before the transistor. However the technology was overlooked because of the success of vacuum tubes, and after 10 years Losev stopped pursuing it and it was forgotten.

The circuit, built in the laboratories of Gernsback's magazine Radio News to Losev's specifications, was a radio frequency oscillator using a negative resistance semiconductor diode (cat whisker detector) (9) made of a crystal of zincite (zinc oxide) with its surface lightly touched by a slender steel wire on an adjustable arm. It required a DC bias voltage of 4 to 30 V, provided by a battery attached to the clips (11). Only certain sites on the crystal surface had negative resistance and the crystal was very sensitive to the pressure of the contact, so a usable contact point had to be found before each use. To adjust the crystal, switch (7) connected a second tuned circuit with a lower resonant frequency, making it oscillate in the audio range. The cat whisker wire was dragged across the crystal surface until the crystal began oscillating, producing a musical tone in the earphones, indicating that a spot with negative resistance had been found. Then the switch was thrown, connecting the crystal to a second tuned circuit which oscillated at radio frequency. The labeled parts are: (1) variometer, (2) variable tuning capacitor, (3) honeycomb tuning coil, (4) 5 pf DC blocking capacitor, (5) choke, (6) 3kΩ potentiometer to adjust crystal bias, (7) switch to connect crystal to adjustment circuit. (8) resistor, (9) zincite-steel point contact crystal diode, (10) earphone connectors, (11) battery connectors.
Date
Source Retrieved August 20, 2014 from Radio News magazine, published by Experimenter Publications, Inc., New York, Vol. 6, No. 3, September 1924, p. 294 archived on American Radio History website
Author Hugo Gernsback
Permission
(Reusing this file)
This 1924 issue of Radio News magazine would have the copyright renewed in 1952. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1951, 1952 and 1953 show no renewal entries for Radio News. Therefore the copyright was not renewed and it is in the public domain.

Licensing

Public domain
This work is in the public domain in the United States because it was published (or registered with the U.S. Copyright Office) before January 1, 1929.

Public domain works must be out of copyright in both the United States and in the source country of the work in order to be hosted on the Commons. If the work is not a U.S. work, the file must have an additional copyright tag indicating the copyright status in the source country.
Note: This tag should not be used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Crystodyne_zincite_oscillator_-_top.png

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