Copper oxide and selenium rectifiers were developed for power applications in the 1930s.

The Harvard was a fixed bias amplifier using a selenium rectifier.

It was once widely used in selenium rectifiers.

But the check I gave him for it was hotter than a selenium rectifier on a shorted circuit.

A selenium rectifier is a type of metal rectifier, invented in 1933.

Selenium rectifiers have no warm-up time unlike high vacuum rectifiers.

Selenium rectifiers have an operating temperature limit of 130 C, and are not suitable for high-frequency circuits.

Selenium rectifiers had a shorter lifespan than desired.

Selenium rectifiers were generally more efficient than metal-oxide types, and could handle higher voltages.

Solid-state technology was in its infancy, represented by copper oxide and selenium rectifiers.

In 1933 selenium rectifiers were invented.

Selenium rectifiers were also cheaper and simpler to specify and install than vacuum tubes.

Zenith used a selenium rectifier in the T/O.

The effects of semiconductor doping were long known empirically in such devices as crystal radio detectors and selenium rectifiers.

Early sets tended to use selenium rectifiers in place of a tube; later sets used silicon diodes.

A selenium rectifier is about the same size as copper oxide rectifiers, but much larger than a silicon or germanium diode.

The development of selenium rectifiers began during the early 1930s, and these replaced copper oxide rectifiers because of their superior efficiencies.

Before the development of silicon semiconductor rectifiers, vacuum tube diodes and copper(I) oxide or selenium rectifier stacks were used.

Selenium rectifiers are made from stacks of aluminum or steel plates coated with about 1 μm of bismuth or nickel.

Specially designed selenium rectifiers were once widely used as EHT rectifiers in television sets and photocopiers.

Doping selenium semiconductors with thallium improves their performance, and therefore it is used in trace amounts in selenium rectifiers.

Selenium rectifiers were once widely used as high-tension rectifiers in transformerless radio and TV sets, before cheaper silicon diodes became available.

Selenium rectifiers had the capability to act as current limiters which can temporarily protect the rectifier during a short circuit and provide stable current for charging batteries.

Vacuum tube rectifiers had efficiencies of only 60% compared to the 85% of selenium rectifiers, partially because vacuum tube rectifiers required heating.

There were even a few "AA4" designs, usually midget sets, only usable in strong-signal metropolitan areas, because most had no IF amplifier (although some replaced the rectifier tube with a selenium rectifier).