Selenium rectifier
![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Selenium_Rectifier.jpg/150px-Selenium_Rectifier.jpg)
A selenium rectifier is a type of
The rectifying properties of selenium, amongst other semiconductors, were observed by Braun, Schuster and Siemens between 1874 and 1883.[2] The photoelectric and rectifying properties of selenium were also observed by Adams and Day in 1876[3] and C. E. Fitts around 1886, but practical rectifier devices were not manufactured routinely until the 1930s. Compared with the earlier copper-oxide rectifier, the selenium cell could withstand higher voltage, but at a lower current capacity per unit area.[4]
Construction
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Structure_selenium_rectifier.svg/220px-Structure_selenium_rectifier.svg.png)
Use
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/26/Selenium_rectifier.agr.jpg/220px-Selenium_rectifier.agr.jpg)
Selenium rectifiers are able to withstand repetitive significant overload without the need of special protective measures. It is commonly used in electroplating rectifier under 200,000 A and electrostatic precipitators operating between 30 and 100 kV[5]
Properties
A selenium rectifier is about the same size as a copper-oxide rectifier, but is much larger than a silicon or germanium diode. Selenium rectifiers have a long but not indefinite service life of 60,000 to 100,000 hours, depending on rating and cooling. The rectifier can show some unforming of the rectifier characteristic after long storage.[6] Each cell can withstand a reverse voltage around 25 volts and has a forward voltage drop around 1 volt, which limits the efficiency at low voltages. Selenium rectifiers have an operating temperature limit of 130 °C and are not suitable for high-frequency circuits.[7]
Replacement
Selenium rectifiers had a shorter lifespan than desired. In the early stage of failure they produce a modest amount of sweet-smelling gas, sometimes described as 'sickly sweet'. At that point the rectification properties are almost totally gone, allowing reverse voltage to leak through the rectifier. During catastrophic failure they produce significant quantities of malodorous and highly toxic
Selenium diode computer logic
In 1961 IBM started developing a low-speed computer logic family
Further reading
- F.T. Selenium Rectifier Handbook; 2nd Ed; Federal Telephone and Radio; 80 pages; 1953. (archive)
- S.T. Selenium Rectifier Handbook; 1st Ed; Sarkes Tarzian; 80 pages; 1950. (archive)
References
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- ISBN 978-1-135-45551-4.
selenium rectifiers, which were invented by Charles E. Fitts in 1933
- ^ books.google.co.uk
- ^ books.google.co.uk
- ISBN 0-86341-227-0, pages 13, 18.
- ISBN 978-1-136-37644-3.
- ISBN 0-12-475902-5, pages 206–207.
- ^ H. P. Westman (ed), Reference Data for Radio Engineers Fifth Edition, Howard W. Sams & Co., Inc. 1968, chapter 13.
- S2CID 93164294.
- ^ "Occupational Health Guideline for Hydrogen Selenide" (PDF). cdc.gov. 1978. Retrieved 2022-10-01.
- ^ PubChem. "Hydrogen selenide". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-10-01.
- ^ Selenium, U.S. Department of the Interior.
- ^ US Patent 3218472: Transistor switch with noise rejection provided by variable capacitance feedback diode.
- ^ a b The 1060 Data Communications System (PDF). IBM. p. 2.