Editing Rectifier (section)

{{short description|Electrical device that converts AC to DC}}
{{Other uses}}
{{Redirect-distinguish|AC/DC converter|AC adapter}}
{{Use dmy dates|date=September 2020}}
[[File:Rectifier.jpg|thumb|right|250px|A thyristor ([[silicon controlled rectifier]]) and associated mounting hardware. The heavy threaded stud attaches the device to a [[heatsink]] to dissipate heat.]]
{{Power engineering}}

A '''rectifier''' is an electrical device that converts [[alternating current]] (AC), which periodically reverses direction, to [[direct current]] (DC), which flows in only one direction.

The process is known as ''rectification'', since it "straightens" the direction of current. Physically, rectifiers take a number of forms, including [[Vacuum tube#Diodes|vacuum tube diodes]], wet chemical cells, [[mercury-arc valve]]s, stacks of copper and [[selenium rectifier|selenium oxide plates]], [[Diode#Semiconductor diodes|semiconductor diodes]], [[silicon-controlled rectifier]]s and other silicon-based semiconductor switches. Historically, even synchronous electromechanical switches and [[motor-generator set]]s have been used. Early radio receivers, called [[crystal radio]]s, used a "[[Crystal detector#Cat whisker detector|cat's whisker]]" of fine wire pressing on a crystal of [[galena]] (lead sulfide) to serve as a point-contact rectifier or "crystal detector".

Rectifiers have many uses, but are often found serving as components of DC [[power supplies]] and [[high-voltage direct current]] power transmission systems. Rectification may serve in roles other than to generate direct current for use as a source of power. As noted, rectifiers can serve as [[detector (radio)|detectors]] of [[radio]] signals. In gas heating systems [[flame rectification]] is used to detect the presence of a flame.

Depending on the type of alternating current supply and the arrangement of the rectifier circuit, the output voltage may require additional smoothing to produce a uniform steady voltage. Many applications of rectifiers, such as power supplies for radio, television and computer equipment, require a ''steady'' constant DC voltage (as would be produced by a [[Electric battery|battery]]).  In these applications the output of the rectifier is smoothed by an [[electronic filter]], which may be a [[capacitor]], [[Choke (electronics)|choke]], or set of capacitors, chokes and [[resistor]]s, possibly followed by a [[voltage regulator]] to produce a steady voltage.

A device that performs the opposite function, that is converting DC to AC, is called an [[inverter]].