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An 8-plate 160 V 450 mA Federal brand selenium rectifier. A selenium rectifier is a type of metal rectifier, invented in 1933. [1] They were used in power supplies for electronic equipment and in high-current battery-charger applications until they were superseded by silicon diode rectifiers in the late 1960s.
Selenium Rectifier. 8-plate 160V 450mA Federal-brand. A metal rectifier is an early type of semiconductor rectifier in which the semiconductor is copper oxide, germanium or selenium. They were used in power applications to convert alternating current to direct current in devices such as radios and battery chargers.
reactive power causes heating in the generators and the transmission lines, thermal limits will require restricting the production and the flow of real power; injection of reactive power into transmission lines causes losses that waste power, forcing an increase in power supplied by the prime mover.
While selenium rectifiers were lighter in weight and used less power than comparable vacuum tube rectifiers, they had the disadvantage of finite life expectancy, increasing resistance with age, and were only suitable to use at low frequencies. Both selenium and copper oxide rectifiers have somewhat better tolerance of momentary voltage ...
A mechanical rectifier is a device for converting alternating current (AC) to direct current (DC) by means of mechanically operated switches. The best-known type is the commutator , which is an integral part of a DC dynamo , but before solid-state devices became available, independent mechanical rectifiers were used for certain applications.
The first electronic device used in power circuits was the electrolytic rectifier - an early version was described by a French experimenter, A. Nodon, in 1904. These were briefly popular with early radio experimenters as they could be improvised from aluminum sheets, and household chemicals.
These selenium rectifiers were used (and are still used) to convert alternating current to direct current in electrical power applications. During 1925–1940, diodes consisting of a pointed tungsten metal wire in contact with a silicon crystal base, were fabricated in laboratories to detect microwaves in the UHF range.
Selenium is found in metal sulfide ores, where it substitutes for sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores. Minerals that are pure selenide or selenate compounds are rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells.