Rectifier
A rectifiers contains sets of diodes that change AC power into DC power, allowing current to flow in one direction but not in the other. This process is known as rectification. Rectifiers are made using mercury arc valves, solid state diodes, vacuum tube diodes, and other technologies. They are components of many power supplies and also used as detectors of radio signals. Almost all rectifiers are comprised of many diodes, which are specifically arranged in order to convert AC to DC more efficiently than if only using one diode.
Several varieties of rectifiers are available on the market. For instance, vacuum-tube rectifiers efficiently provide moderate, constant power. They have essentially infinite resistance to current flow in the reverse direction because their tube does not conduct when the plate is negative. A semiconductor rectifier, on the other hand, has constant forward and reverse resistances and has the advantage of not needing a filament or heater supply.
Rectifiers are used in virtually all electronic equipment. They are often used within various power supplies when the electronics need a DC supply but the main power comes from an AC supply. Rectifiers are also usually involved in converting DC voltage from one level to another or in the detection of amplitude modulated radio signals.