Rectifiers

Power rectifiers, using copper oxide and selenium, were developed in the 1920s and became commercially important as an alternative to vacuum tube rectifiers.

A power supply using a transformer with several windings, one or more rectifiers (which may themselves be vacuum tubes), and large filter capacitors provided the required direct current voltages from the alternating current source.

As trains began to be powered by transformers and rectifiers more sophisticated throttles appeared, and soon trains powered by AC contained mechanisms to change direction or go into neutral gear when the operator cycled the power.

Detector and power rectifiers could not amplify a signal.

High-power rectifiers use mercury vapor to achieve a lower forward voltage drop than high-vacuum tubes.

Loads such as rectifiers distort the waveforms from the sinusoidal shape.

One of the earliest suitable rectifiers was the copper oxide rectifier developed and manufactured by Union Switch & Signal Company, Swissvale, Pennsylvania, later part of Westinghouse Brake and Signal Company, from 1927.

Power conversion main Schematic of basic AC-to-DC power supply Rectifiers are constructed from diodes, where they are used to convert alternating current (AC) electricity into direct current (DC).

Such rectifiers may be used for battery charging, electrolysis processes such as aluminium production or for operation of DC motors.

The most aggressive contributor to corrosion of underground plant is dc stray current from electrified rail transportation systems, cathodic protection rectifiers, or welding and mining operations.

Though once widely used, selenium rectifiers have mostly been replaced (or are being replaced) by silicon-based devices.

Throughout the vacuum tube era, valve diodes were used in analog signal applications and as rectifiers in DC power supplies in consumer electronics such as radios, televisions, and sound systems.

To automatically match source polarity to LED devices, rectifiers can be used.

Westinghouse Electric (1886) was a major manufacturer of these rectifiers.