Early crystal rectifiers and diodes

First German old semiconductor related web page, online since 12/12/1997.

Last update: 12/25/2005

You will find here:

• A short semiconductor history

• Part of my semiconductor collection

• Semiconductor advertising

• Early semiconductor list

Crystal rectifiers were employed for demodulation quite early (1905) in radio technology. Crystal radio sets used various semiconductor crystals. In the first years of wireless technology fritters, also called coherers and Schloemilch-cells (1902) were employed to detect radio frequency. The Sirutor-rectifier exists since 1925, Selen power supply rectifiers since 1930. You will find more information about crystal rectifiers and crystal radio sets at: Gollum´s Crystal Receiver World.

Crystal detectors with their different crystal types were quite efficient but were awkward to use. The Sirutor and later germanium point-contact diodes were not quite as sensitive but easy to use. The first germanium point-contact diodes were developed in the U.S. in 1949/50. Schottky diodes were in use since 1963.

In Germany germanium diodes were employed since 1952 (1950). Early suppliers were Intermetall, SAF, Proton, Dr. Rost , Elektro Spezial, Siemens, TeKaDe and Telefunken.

Early Germanium diodes 1950 / Fruehe Germanium Dioden 1950

Part of my "Early Semiconductor" collection.

(Teil meiner Halbleiter-Sammlung)

AA112

AA119

AA132

1950-1954

Who has more information about the above shown semiconductors?

Advertising of Proton, 1952