Semiconductor archeology, or a tribute to an unknown predecessor. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Beginner radio amateur
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At the beginning of the radio era, listeners received transmissions on detector receivers. These receivers contained an antenna, tuner, detector, and headphones (Fig. 1).
Rice. 1. Classic detector receiver
The detector was an anisotropic galenic (lead sulfide) crystal fixed in a small cup. One or more metal wires ("cat's whiskers") were connected to the crystal. These wires were made of gold, brass, copper or steel. Such a detector allowed the electric current to flow better in one direction than in the other, which made it possible to rectify high-frequency signals and extract speech or music from them. This phenomenon was called "one-way conduction".
This discovery of rectifying properties in some crystals was made by F. Brown in 1874.
The practical application of this discovery was found by Greenleaf Witter Picard (1877 - 1956)
In 1938 the nature of these processes was still not clear. there was not enough knowledge in the field of molecular physics and solid state chemistry. It was believed that there was some kind of thermal action, or it was an electrical phenomenon. In 1920-1922, a huge amount of research was done in Russia and in the USA. But the evolution of radio electronics was determined by the rapid development of vacuum tubes. So because of this, the results and knowledge of the early days were almost forgotten.
It wasn't until 1945 that real research began, producing results that were the forerunners of today's semiconductors. Among this:
Invention of the point transistor by scientists Bardeen, Brattain and Shockley (Nobel Prize 1926.)
The discovery of the tunnel effect by the Japanese scientist L. Esaki (Nobel Prize in 1973.)
We will try to create a list of materials used in the years 1920-1938. (This description does not claim to be exhaustive.)
DETECTORS:
Three kinds:
- Contact between crystal and tip.
- A contact (or connection) between two identical crystals.
- A contact (or connection) between two different crystals.
Many crystals have been tested:
- Bornite
- Carborundum (Carbon-Silicon combination)
- Cassiterite
- Cerussite
- Chalcopyrite
- Galena
- Ghana
- Graphite
- Hessit
- Hematite
- Hertzite
- Malachite
- Molybdenite
- Pyrites
- Silicon
- Bismuth sulfide
- Tellurium
- Ulmanit
- Zincite...
Most popular combinations:
Contacts:
- Galena - Copper(Brass, Silver)
- Molybdenite - Silver
- Iron Pyrite - Gold
- Carborundum - steel
- Copper - Silicon
- Zincite - Steel
And transitions:
- Chalcopyrite - Zincite (known as Pericone)
Today we call these devices DIODES.
The electrical and mechanical characteristics of these diodes depend on the contact (or junction) pressure and on the polarization voltage.
An example of prehistoric characteristics is shown in Figure 2.
Rice. 2: I Contact Perikon (Zincite-Chalcopyrite); II Contact Carborundum-Steel; III Contact Zincite-Steel
Zincite was obtained from natural zinc oxide (ZnO) by heating it in an electric arc in the presence of peroxide or manganese dioxide.
In our opinion, the most interesting is the contact between Zincite and Steel (and sometimes carbon). But the old characteristics in Fig. 2 do not show the most exciting aspect.
In 1923, Oleg Losev (1903-1942) managed to create a high-frequency generator using such a detector. But the detector was polarized. This means that there is a zone of negative resistance on the characteristic curve of the diode. And this brings to mind the tunnel diode, invented half a century later.
Figure 3 shows the characteristics of conventional and tunnel diodes, where this zone is visible.
Rice. 3. Tunnel diode
The green curve has a negative resistance zone between 200 and 300 mV.
Unknown predecessors took advantage of this discovery and were able to create some semiconductor devices ahead of time. Here they are :
- heterodynes
- regenerative receivers
- low frequency modulators
- autodynes
- ULF
- UHF (8...12 MHz)
- transceivers...
These schemes were part of the so-called CRYSTADINE system (sometimes called "KRISTADIN"). But in those days, all this was ignored and forgotten due to the rapid development of lamp technology.
Figures 4-7 show four original schematics of the "Crystadyne" system. They were printed before 1938.
Rice. 4. Heterodyne with Zincite
Rice. 5. Cristadyne receiver
Rice. 6. Local oscillator with Zincite for short waves
Rice. 7. Zincite modulator - Low frequency "ticker"
Author: Allen Renee
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