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Forum » Radio- and technical History » Technical history: 1920 and later » Crystodyne
Roy Johnson
GB  Articles: 284
Schem.: 21
Pict.: 132
20.Jul.09 21:09

Count of Thanks: 12
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The Crystodyne discovery was announced in 1924.

It was observed that radio frequency oscillations could be produced when a voltage was applied  to various crystal junctions in a tuned circuit arrangement similar to a crystal set receiver.

See the attached  3 pages for details of the 1924 paper.

The principle would seem to be that of the tunnel diode whereby a negative impedance region is created in the voltage/current characteristics.  

  • Was this principle ever used commercially?
  • Has anyone carried out any recent  experiments? 
  • Is the action the same as the tunnel diode or is it a different mechanism?



Bryce Ringwood
Bryce Ringwood
ZA  Articles: 79
Schem.: 17
Pict.: 106
20.Jul.09 21:52

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I discovered this web site some time ago - it looks as if the Crystodyne is still alive and well. 

I sometimes think its remarkable that transistors weren't invented before vacuum tubes.

Regards - Bryce


Roy Johnson
GB  Articles: 284
Schem.: 21
Pict.: 132
20.Jul.09 22:15

Count of Thanks: 7
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Many thanks, Bryce.

Yes,  research missed a trick, but the advanced tools for crystallography and were not available in the 1920s.  

Even so, it does seem that the observation was not followed through in any depth at that time.  Investment was being made in tube/valve development and the curiosity remained as such.   

If it had not been for the electric light, the chemists investigating gas mantles may very well have moved into crystals!

Regards,  Roy


Georg Beckmann
Georg Beckmann
D  Articles: 438
Schem.: 15
Pict.: 3
26.Jul.09 11:10

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Hi Roy,

here is an interesting article to the subject discussed.

Georg Beckmann


Nikolaus Löwe
Nikolaus Löwe
D  Articles: 213
Schem.: 167
Pict.: 1185
26.Jul.09 21:19

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Der friends,

may I refer you to the paper by Oleg V. Lossev titled "Luminous carborundum detector and detection effect and oscillations with crystals", Philosophical Magazine 5, 1024-1044, from 1928.

I have attached the first few pages of the article that deal explicitly with oscillating crystals. The complete paper as pdf requires about 3 MB, which is too much to attach.

In his paper, Lossev gives credit to Eccles for the discovery of the oscillating property of crystals in 1910.

It is also noteworthy that Lossev studied the luminescence of SiC, which as far as I know is nowadays used for blue LEDs.

Because of his work, Lossev was lately credited with inventing the LED (Nature Photonics, April 2007, Nikolay Zheludev).


Nikolaus Loewe