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Contents

1 Rectifier devices

2 Rectifier circuits

3 Rectifier losses

4 Rectifier output smoothing

5 Applications

6 Rectification technologies

7 Current research

http://en.wikipedia.org/wiki/Rectifier#Rectifier_deviceshttp://en.wikipedia.org/wiki/Rectifier#Rectifier_circuitshttp://en.wikipedia.org/wiki/Rectifier#Rectifier_losseshttp://en.wikipedia.org/wiki/Rectifier#Rectifier_output_smoothinghttp://en.wikipedia.org/wiki/Rectifier#Applicationshttp://en.wikipedia.org/wiki/Rectifier#Rectification_technologieshttp://en.wikipedia.org/wiki/Rectifier#Current_researchhttp://en.wikipedia.org/wiki/Rectifier#Rectifier_circuitshttp://en.wikipedia.org/wiki/Rectifier#Rectifier_losseshttp://en.wikipedia.org/wiki/Rectifier#Rectifier_output_smoothinghttp://en.wikipedia.org/wiki/Rectifier#Applicationshttp://en.wikipedia.org/wiki/Rectifier#Rectification_technologieshttp://en.wikipedia.org/wiki/Rectifier#Current_researchhttp://en.wikipedia.org/wiki/Rectifier#Rectifier_devices

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Rectifier

A rectifier diode (silicon controlled rectifier) and associated mounting hardare! "he heav#

threaded stud attaches the device to a heatsin$to dissipate heat!

A rectifieris an electrical device that convertsalternating current(AC)% hichperiodicall# reverses direction% to direct current(&C)% hich flos in onl# one direction!"he process is $non as rectification! 'h#sicall#% rectifiers ta$e a numer of forms%including vacuum tuediodes%mercur#arc valves% copper and selenium o*iderectifiers%semiconductor diodes% siliconcontrolled rectifiersand other siliconasedsemiconductor sitches! +istoricall#% even s#nchronous electromechanical sitchesand motors have een used! ,arl# radio receivers% called cr#stal radios% used a -cat.shis$er- of fine ire pressing on a cr#stal of galena(lead sulfide) to serve as a pointcontact rectifier or -cr#stal detector-!

Rectifiers have man# uses% ut are often found serving as components of &C poer

suppliesand highvoltage direct currentpoer transmission s#stems! Rectification ma#serve in roles other than to generate direct current for use as a source of poer! Asnoted% detectorsof radiosignals serve as rectifiers! /n gas heating s#stems flamerectificationis used to detect presence of a flame!

0ecause of the alternating nature of the input AC sine ave% the process of rectificationalone produces a &C current that% though unidirectional% consists of pulses of current!an# applications of rectifiers% such as poer supplies for radio% television andcomputer euipment% reuire a steadyconstant &C current (as ould e produced #a atter#)! /n these applications the output of the rectifier is smoothed # an electronicfilter(usuall# a capacitor) to produce a stead# current!

A more comple* circuitr# device that performs the opposite function% converting &C toAC% is called an inverter!

Rectifier devices0efore the development of silicon semiconductor rectifiers% vacuum tue thermionicdiodesand copper o*ide or seleniumased metal rectifierstac$s ere used! 1ith theintroduction of semiconductor electronics% vacuum tue rectifiers ecame osolete%e*cept for some enthusiasts of vacuum tue audio euipment! or poer rectification

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from ver# lo to ver# high current% semiconductor diodes of various t#pes (unctiondiodes% 8chott$# diodes% etc!) are idel# used!

9ther devices that have control electrodes as ell as acting as unidirectional currentvalves are used here more than simple rectification is reuired:e!g!% here varialeoutput voltage is needed! +ighpoer rectifiers% such as those used in highvoltage

direct currentpoer transmission% emplo# silicon semiconductor devices of varioust#pes! "hese are th#ristorsor other controlled sitching solidstate sitches% hicheffectivel# function as diodes to pass current in onl# one direction!

Rectifier circuitsRectifier circuits ma# e singlephase or multiphase (three eing the most commonnumer of phases)! ost lo poer rectifiers for domestic euipment are singlephase%ut threephase rectification is ver# important for industrial applications and for thetransmission of energ# as &C (+;&C)!

Single-phase rectifiersHalf-wave rectification/n half ave rectification of a singlephase suppl#% either the positive or negative half ofthe AC ave is passed% hile the other half is loc$ed! 0ecause onl# one half of theinput aveform reaches the output% mean voltage is loer! +alfave rectificationreuires a single diode in a singlephase suppl#% or three in a threephase suppl#!Rectifiers #ield a unidirectional ut pulsating direct current< halfave rectifiers producefar more ripple than fullave rectifiers% and much more filtering is needed to eliminateharmonics of the AC freuenc# from the output!

+alfave rectifier

"he noload output &C voltage of an ideal half ave rectifier for a sinusoidal inputvoltage is=2

here=

Vdc% Vav the &C or average output voltage%

Vpea$% the pea$ value of the phase input voltages%

Vrms% the rootmeansuare value of output voltage!

Full-wave rectification

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A fullave rectifier converts the hole of the input aveform to one ofconstant polarit# (positive or negative) at its output! ullave rectificationconverts oth polarities of the input aveform to pulsating &C (directcurrent)% and #ields a higher average output voltage! "o diodes anda center tappedtransformer% or four diodes in a ridge configurationand an#

AC source (including a transformer ithout center tap)% are needed!8inglesemiconductor diodes% doule diodes ith common cathode or commonanode% and fourdiode ridges% are manufactured as single components!

>raet? ridge rectifier= a fullave rectifier using 4 diodes!

or singlephase AC% if the transformer is centertapped% then to diodes

ac$toac$ (cathodetocathode or anodetoanode% depending uponoutput polarit# reuired) can form a fullave rectifier! "ice as man# turnsare reuired on the transformer secondar# to otain the same output voltagethan for a ridge rectifier% ut the poer rating is unchanged!

ullave rectifier using acenter taptransformer and 2 diodes!

ullave rectifier% ith vacuum tue having to anodes!

"he averageand rootmeansuarenoload output voltages of an idealsinglephase fullave rectifier are=

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;er# common doulediode rectifier vacuum tuescontained a singlecommon cathodeand to anodesinside a single envelope% achieving fullave rectification ith positive output! "he 5@4 and 53 ere populare*amples of this configuration!

Three-phase rectifiers

3phase AC input% half and fullave rectified &C output aveforms

8inglephase rectifiers are commonl# used for poer supplies for domesticeuipment! +oever% for most industrial and highpoer applications% threephaserectifier circuits are the norm! As ith singlephase rectifiers% threephase rectifiers can ta$e the form of a halfave circuit% a fullave circuitusing a centertapped transformer% or a fullave ridge circuit!

"h#ristorsare commonl# used in place of diodes to create a circuit that canregulate the output voltage! an# devices that provide direct currentactuall# generatethreephase AC! or e*ample% an automoile

alternatorcontains si* diodes% hich function as a fullave rectifier foratter# charging!

Three-phase, half-wave circuit

An uncontrolled threephase% halfave circuit reuires three diodes% oneconnected to each phase! "his is the simplest t#pe of threephase rectifierut suffers from relativel# high harmonicdistortion on oth the AC and &Cconnections! "his t#pe of rectifier is said to have a pulse-numberof three%

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since the output voltage on the &C side contains three distinct pulses perc#cle of the grid freuenc#!

Three-phase, full-wave circuit using center-tapped transformer

/f the AC suppl# is fed via a transformer ith a center tap% a rectifier circuitith improved harmonic performance can e otained! "his rectifier no

reuires si* diodes% one connected to each end of each transformersecondar# inding! "his circuit has a pulsenumer of si*% and in effect% cane thought of as a si*phase% halfave circuit!

0efore solid statedevices ecame availale% the halfave circuit% and thefullave circuit using a centertapped transformer% ere ver# commonl#used in industrial rectifiers using mercur#arc valves!"his as ecause thethree or si* AC suppl# inputs could e fed to a corresponding numer ofanode electrodes on a single tan$% sharing a common cathode!

ith the advent of diodes and th#ristors% these circuits have ecome lesspopular and the threephase ridge circuit has ecome the most common

circuit!

Three-phase half-wave rectifier circuit usingthyristorsas the switching elements,

ignoring supply inductance

Three-phase full-wave rectifier circuit usingthyristorsas the switching elements

center-tapped transformer, ignoring supply inductance

Three-phase bridge rectifier

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&isassemled automoilealternator%shoing the si* diodes that comprise a fullave threephase ridge rectifier!

or an uncontrolled threephase ridge rectifier% si* diodes are used% and thecircuit again has a pulse numer of si*! or this reason% it is also commonl#referred to as a six-pulse bridge!

or lopoer applications% doule diodes in series% ith the anode of thefirst diode connected to the cathode of the second% are manufactured as asingle component for this purpose! 8ome commerciall# availale doulediodes have all four terminals availale so the user can configure them forsinglephase split suppl# use% half a ridge% or threephase rectifier!

or higherpoer applications% a single discrete device is usuall# used foreach of the si* arms of the ridge! or the ver# highest poers% each arm ofthe ridge ma# consist of tens or hundreds of separate devices in parallel(here ver# high current is needed% for e*ample in aluminium smelting) or inseries (here ver# high voltages are needed% for e*ample in highvoltagedirect currentpoer transmission)!

"hreephase fullave ridge rectifier circuit usingth#ristorsas the sitching elements% ignoring suppl# inductance

or a threephase fullave diode rectifier% the ideal% noload average outputvoltage is

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/f th#ristors are used in place of diodes% the output voltage is reduced # afactor cos(B)=

9r% e*pressed in terms of the line to line input voltage=5

here=

Vpea$% the pea$ value of the line to line input voltages%

Vpea$% the pea$ value of the phase (line to neutral) input voltages%

B% firing angle of the th#ristor (D if diodes are used to perform rectification)

"he aove euations are onl# valid hen no current is dran fromthe AC suppl# or in the theoretical case hen the AC suppl#

connections have no inductance! /n practice% the suppl#inductance causes a reduction of &C output voltage ithincreasing load% t#picall# in the range 1DE2DF at full load!

"he effect of suppl# inductance is to slo don the transferprocess (called commutation) from one phase to the ne*t! Asresult of this is that at each transition eteen a pair of devices%there is a period of overlapduring hich three (rather than to)devices in the ridge are conducting simultaneousl#! "he overlapangleis usuall# referred to # the s#mol G (or u)% and ma# e2D 3DH at full load!

ith suppl# inductance ta$en into account% the output voltage ofthe rectifier is reduced to=

"he overlap angle G is directl# related to the &C current% and theaove euation ma# e ree*pressed as=

here=

Lc% the commutating inductance per phase

Id% the direct current

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Three-phase Graet z br idge rec ti fi er at alpha=0 wi thout overl ap Three-phase Graet z b ridge rec ti fi er at a

Three-phase controlled Graetz bridge rectifier at alpha=20 with overlap angle of 20 Three-phase controlled Graetz bridge re

Twelve-pulse bridge

"elve pulse ridge rectifier usingth#ristorsas the sitching elements

Although etter than singlephase rectifiers or threephasehalfave rectifiers% si*pulse rectifier circuits still produceconsiderale harmonic distortion on oth the AC and &Cconnections! or ver# highpoer rectifiers the twelve-

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pulse bridgeconnection is usuall# used! A telvepulseridge consists of to si*pulse ridge circuits connectedin series% ith their AC connections fed from a suppl#transformer that produces a 3DH phase shift eteen theto ridges! "his cancels man# of the characteristic

harmonics the si*pulse ridges produce!"he 3D degree phase shift is usuall# achieved # using atransformer ith to sets of secondar# indings% one instar (#e) connection and one in delta connection!

Voltage-multiplying rectifiers

8itchale full ridgeIvoltage douler!

"he simple half ave rectifier can e uilt in to electricalconfigurations ith the diode pointing in oppositedirections% one version connects the negative terminal ofthe output direct to the AC suppl# and the other connectsthe positive terminal of the output direct to the AC suppl#!0# comining oth of these ith separate outputsmoothing it is possile to get an output voltage of nearl#doule the pea$ AC input voltage! "his also provides a tapin the middle% hich allos use of such a circuit as a splitrail poer suppl#!

A variant of this is to use to capacitors in series for the

output smoothing on a ridge rectifier then place a sitcheteen the midpoint of those capacitors and one of the

AC input terminals! ith the sitch open% this circuit actsli$e a normal ridge rectifier! ith the sitch closed% it actli$e a voltage douling rectifier! /n other ords% this ma$esit eas# to derive a voltage of roughl# 32D ; (J15F%appro*!) &C from an# 12D ; or 23D ; mains suppl# in theorld% this can then e fed into a relativel#

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simple sitchedmode poer suppl#! +oever% for a givendesired ripple% the value of oth capacitors must e ticethe value of the single one reuired for a normal ridgerectifier< hen the sitch is closed each one must filter theoutput of a halfave rectifier% and hen the sitch is open

the to capacitors are connected in series ith an euivalent value of half one of them!

Coc$croft alton ;oltage multiplier

Cascaded diode and capacitor stages can e added to ma$e a voltage multiplier (Coc$roftaltoncircuit)! "hese circuits are capale of producing a &C output voltage potential tens of times that of thepea$ AC input voltage% ut are limited in current capacit# and regulation! &iode voltage multipliers%freuentl# used as a trailing oost stage or primar# high voltage (+;) source% are used in +; laser

poer supplies% poering devices such ascathode ra# tues(CR") (li$e those used in CR" asedtelevision% radar and sonar displa#s)% photon amplif#ing devices found in image intensif#ing and photomultiplier tues ('")% and magnetron ased radio f reuenc# (R) devices used in radar transmittersand microave ovens! 0efore the introduction of semiconductor electronics%transformerless poeredvacuum tue receiverspoered directl# from AC poer sometimes used voltage doulers togenerate aout 17D ;&C from a 1DDE12D ; poer line!

Rectifier losses

A real rectifier characteristicall# drops part of the input voltage (a voltage drop% for silicon devices% oft#picall# D!7 volts plus an euivalent resistance% in general nonlinear):and at high freuencies%distorts aveforms in other a#s! @nli$e an ideal rectifier% it dissipates some poer!

An aspect of most rectification is a loss from the pea$ input voltage to the pea$ output voltage%caused # the uiltin voltage drop across the diodes (around D!7 ; for ordinar# siliconpEnunctiondiodes and D!3 ; for8chott$# diodes)! +alfave rectification and fullave rectification usinga centertapped secondar# produces a pea$ voltage loss of one diode drop! 0ridge rectification has aloss of to diode drops! "his reduces output voltage% and limits the availale output voltage if a ver#

lo alternating voltage must e rectified! As the diodes do not conduct elo this voltage% the circuitonl# passes current through for a portion of each halfc#cle% causing short segments of ?ero voltage(here instantaneous input voltage is elo one or to diode drops) to appear eteen each-hump-!

'ea$ loss is ver# important for lo voltage rectifiers (for e*ample% 12 ; or less) ut is insignificant inhighvoltage applications such as +;&C!

Rectifier output smoothing

"he ACinput (#ello)and&C output (green) ofa halfave rectifierith a smoothing capacitor! Kote the ripple in the &C signal!

hile halfave and fullave rectification can deliver unidirectional current% neither produces aconstant voltage! 'roducing stead# &C from a rectified AC suppl# reuires a smoothing circuitor filter!6/n its simplest form this can e ust a reservoir capacitoror smoothing capacitor% placed atthe &C output of the rectifier! "here is still an AC ripplevoltage component at the poer suppl#freuenc# for a halfave rectifier% tice that for fullave% here the voltage is not completel#smoothed!

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RCilterRectifier= "hiscircuit asdesigned andsimulated us ingultisimL softare!

8i?ing of the capacitor represents atradeoff!or a given load% a larger capacitor reduces ripple utcosts more and creates higher pea$ currents in the transformer secondar# and in the suppl# thatfeeds it! "he pea$ current is set in principle # the rate of rise of the suppl# voltage on the rising edgeof the incoming sineave% ut in practice it is reduced # the resistance of the transformer indings!/n e*treme cases here man# rectifiers are loaded onto a poer distriution circuit% pea$ currentsma# cause difficult# in maintaining a correctl# shaped sinusoidal voltage on the ac suppl#!

"o limit ripple to a specified value the reuired capacitor si?e is proportional to the load current and

inversel# proportional to the suppl# freuenc# and the numer of output pea$s of the rectifier perinput c#cle! "he load current and the suppl# freuenc# are generall# outside the control of thedesigner of the rectifier s#stem ut the numer of pea$s per input c#cle can e affected # the choiceof rectifier design!

A halfave rectifier onl# gives one pea$ per c#cle% and for this and other reasons is onl# used in ver#small poer supplies! A full ave rectifier achieves to pea$s per c#cle% the est possile ith asinglephase input! or threephase inputs a threephase ridge gives si* pea$s per c#cle! +ighernumers of pea$s can e achieved # using transformer netor$s placed efore the rectifier toconvert to a higher phase order!

"o further reduce ripple% acapacitorinput filtercan e used! "his complements the reservoircapacitor ith acho$e(inductor) and a secondfilter capacitor%so that a steadier &C output can eotained across the terminals of the filter capacitor! "he cho$e presents a high impedanceto theripple current!6or use at poerline freuencies inductors reuire coresof iron or other magneticmaterials% and add eight and si?e! "heir use in poer supplies for electronic euipment hastherefore dindled in favour of semiconductor circuits such as voltage regulators!

A more usual alternative to a filter% and essential if the &C load reuires ver# lo ripple voltage% is tofollo the reservoir capacitor ith an active voltage regulatorcircuit! "he reservoir capacitor must e

large enough to prevent the troughs of the ripple dropping elo the minimum voltage reuired # theregulator to produce the reuired output voltage! "he regulator serves oth to significantl# reduce theripple and to deal ith variations in suppl# and load characteristics! /t ould e possile to use asmaller reservoir capacitor (these can e large on highcurrent poer supplies) and then appl# somefiltering as ell as the regulator% ut this is not a common strateg#! "he e*treme of this approach is todispense ith the reservoir capacitor altogether and put the rectified aveform straight into a cho$einput filter! "he advantage of this circuit is that the current aveform is smoother and conseuentl#the rectifier no longer has to deal ith the current as a large current pulse% ut instead the currentdeliver# is spread over the entire c#cle! "he disadvantage% apart from e*tra si?e and eight% is thatthe voltage output is much loer E appro*imatel# the average of an AC halfc#cle rather than thepea$!

Applications

"he primar# application of rectifiers is to derive &C poer from an AC suppl# (AC to &C converter)!;irtuall# all electronic devices reuire &C% so rectifiers are used inside the poer supplies of virtuall#all electronic euipment!

Converting &C poer from one voltage to another is much more complicated! 9ne method of &Cto&C conversion first converts poer to AC (using a device called aninverter)% then uses a transformerto change the voltage% and finall# rectifies poer ac$ to &C! A freuenc# of t#picall# several tens of$ilohert? is used% as this reuires much smaller inductance than at loer freuencies and oviates theuse of heav#% ul$#% and e*pensive ironcored units!

http://en.wikipedia.org/wiki/Multisimhttp://en.wikipedia.org/wiki/Multisimhttp://en.wikipedia.org/wiki/Multisimhttp://en.wikipedia.org/wiki/Tradeoffhttp://en.wikipedia.org/wiki/Tradeoffhttp://en.wikipedia.org/wiki/Tradeoffhttp://en.wikipedia.org/wiki/Capacitor-input_filterhttp://en.wikipedia.org/wiki/Capacitor-input_filterhttp://en.wikipedia.org/wiki/Capacitor-input_filterhttp://en.wikipedia.org/wiki/Choke_(electronics)http://en.wikipedia.org/wiki/Choke_(electronics)http://en.wikipedia.org/wiki/Choke_(electronics)http://en.wikipedia.org/wiki/Filter_capacitorhttp://en.wikipedia.org/wiki/Filter_capacitorhttp://en.wikipedia.org/wiki/Filter_capacitorhttp://en.wikipedia.org/wiki/Electrical_impedancehttp://en.wikipedia.org/wiki/Rectifier#cite_note-dcp-6http://en.wikipedia.org/wiki/Rectifier#cite_note-dcp-6http://en.wikipedia.org/wiki/Magnetic_corehttp://en.wikipedia.org/wiki/Voltage_regulatorhttp://en.wikipedia.org/wiki/Voltage_regulatorhttp://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Inverter_(electrical)http://en.wikipedia.org/wiki/Multisimhttp://en.wikipedia.org/wiki/Tradeoffhttp://en.wikipedia.org/wiki/Capacitor-input_filterhttp://en.wikipedia.org/wiki/Choke_(electronics)http://en.wikipedia.org/wiki/Filter_capacitorhttp://en.wikipedia.org/wiki/Electrical_impedancehttp://en.wikipedia.org/wiki/Rectifier#cite_note-dcp-6http://en.wikipedia.org/wiki/Magnetic_corehttp://en.wikipedia.org/wiki/Voltage_regulatorhttp://en.wikipedia.org/wiki/Inverter_(electrical)

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A small motorgeneratorset

A motor-generator set% or the similar rotary converter% is not strictl# a rectifier as it does notactuall# rectifycurrent% ut rathergenerates&C from an AC source! /n an -> set-% the shaft of anAC motor is mechanicall# coupled to that of a &Cgenerator! "he &C generator produces multiphasealternating currents in its armatureindings% hich acommutatoron the armature shaft converts intoa direct current output< or ahomopolar generatorproduces a direct current ithout the need for acommutator! > sets are useful for producing &C for raila# traction motors% industrial motors andother highcurrent applications% and ere common in man# highpoer &!C! uses (for e*ample%caronarc lamp proectors for outdoor theaters) efore highpoer semiconductors ecame idel#availale!

lectrolytic

"heelectrol#ticrectifierLas a device from the earl# tentieth centur# that is no longer used! A homemade version is illustrated in the 1M13 oo$ The Boy MechanicMut it ould onl# e suitale for useat ver# lo voltages ecause of the lorea$don voltageand the ris$ ofelectric shoc$!A more

comple* device of this $ind as patented # >! ! Carpenter in 1M2L (@8 'atent 1671M7D)!1D

hen to different metals are suspended in an electrol#te solution% direct current floing one a#through the solution sees less resistance than in the other direction! ,lectrol#tic rectifiers mostcommonl# used an aluminum anode and a lead or steel cathode% suspended in a solution of triammonium orthophosphate!

"he rectification action is due to a thin coating of aluminum h#dro*ide on the aluminum electrode%formed # first appl#ing a strong current to the cell to uild up the coating! "he rectification process istemperaturesensitive% and for est efficienc# should not operate aove L6 H (3D HC)! "here is alsoarea$don voltagehere the coating is penetrated and the cell is shortcircuited! ,lectrochemicalmethods are often more fragile than mechanical methods% and can e sensitive to usage variations%hich can drasticall# change or completel# disrupt the rectification processes!

8imilar electrol#tic devices ere used as lightning arresters around the same era # suspendingman# aluminium cones in a tan$ of triammonium orthophosphate solution! @nli$e the rectifier aove%onl# aluminium electrodes ere used% and used on A!C!% there as no polari?ation and thus norectifier action% ut the chemistr# as similar!11

"he modern electrol#tic capacitor% an essential component of most rectifier circuit configurations asalso developed from the electrol#tic rectifier!

!lasma type

A rectifier used inhighvoltage direct current(+;&C) poer transmission s#stems and industrialprocessing eteen aout 1MDM to 1M75 is a mercury-arc rectifieror mercury-arc valve! "he device isenclosed in a ulous glass vessel or large metal tu! 9ne electrode% the cathode% is sumerged in apool of liuid mercur# at the ottom of the vessel and one or more high purit# graphite electrodes%

http://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Homopolar_generatorhttp://en.wikipedia.org/wiki/Homopolar_generatorhttp://en.wikipedia.org/wiki/Homopolar_generatorhttp://en.wikipedia.org/wiki/Electrolytichttp://en.wikipedia.org/wiki/Electrolytichttp://en.wikipedia.org/wiki/Electrolytichttp://en.wikipedia.org/wiki/Rectifier#cite_note-Hawkins1914-8http://en.wikipedia.org/wiki/Rectifier#cite_note-Hawkins1914-8http://en.wikipedia.org/wiki/Rectifier#cite_note-Hawkins1914-8http://en.wikipedia.org/wiki/Rectifier#cite_note-9http://en.wikipedia.org/wiki/Rectifier#cite_note-9http://en.wikipedia.org/wiki/Rectifier#cite_note-9http://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Rectifier#cite_note-10http://en.wikipedia.org/wiki/Rectifier#cite_note-10http://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Rectifier#cite_note-Society1920-11http://en.wikipedia.org/wiki/High-voltage_direct_currenthttp://en.wikipedia.org/wiki/High-voltage_direct_currenthttp://en.wikipedia.org/wiki/High-voltage_direct_currenthttp://en.wikipedia.org/wiki/Cathodehttp://en.wikipedia.org/wiki/Cathodehttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Homopolar_generatorhttp://en.wikipedia.org/wiki/Electrolytichttp://en.wikipedia.org/wiki/Rectifier#cite_note-Hawkins1914-8http://en.wikipedia.org/wiki/Rectifier#cite_note-9http://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Electric_shockhttp://en.wikipedia.org/wiki/Rectifier#cite_note-10http://en.wikipedia.org/wiki/Breakdown_voltagehttp://en.wikipedia.org/wiki/Rectifier#cite_note-Society1920-11http://en.wikipedia.org/wiki/High-voltage_direct_currenthttp://en.wikipedia.org/wiki/Cathode

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called anodes%are suspended aove the pool! "here ma# e several au*iliar# electrodes to aid instarting and maintaining the arc! hen an electric arc is estalished eteen the cathode pool andsuspended anodes% a stream of electrons flos from the cathode to the anodes through the ioni?edmercur#% ut not the other a# (in principle% this is a higherpoer counterpart to flame rectification%hich uses the same onea# current transmission properties of the plasma naturall# present in aflame)!

"hese devices can e used at poer levels of hundreds of $iloatts% and ma# e uilt to handle oneto si* phases of AC current! ercur#arc rectifiers have een replaced # silicon semiconductorrectifiers and highpoerth#ristorcircuits in the mid 1M7Ds! "he most poerful mercur#arc rectifiers

ever uilt ere installed in theanitoa +#droKelson River 0ipole+;&C proect% ith a cominedrating of more than 1 > and 45D $;!1213

"he>eneral ,lectric"ungar rectifier as anargongasfilled electron tuedevice ith a tungstenfilament cathode and a caron utton anode! /t operated similarl# to the thermionic vacuum tuediode% ut the gas in the tue ioni?ed during forard conduction% giving it a much loer forardvoltage drop so it could rectif# loer voltages! /t as used for atter# chargers and similarapplications from the 1M2Ds until loercost metal rectifiers%and later semiconductor diodes%supplanted it! "hese ere made up to a fe hundred volts and a fe amperes rating% and in somesi?es strongl# resemled anincandescent lampith an additional electrode!

"he DN4 as a gasfilled rectifier tue commonl# used in vacuum tuecar radios in the 1M4Ds and1M5Ds! /t as a conventional fullave rectifier tue ith to anodes and one cathode% ut asuniue in that it had no filament (thus the -D- in its t#pe numer)! "he electrodes ere shaped suchthat the reverse rea$don voltage as much higher than the forard rea$don voltage! 9nce therea$don voltage as e*ceeded% the DN4 sitched to a loresistance state ith a forard voltagedrop of aout 24 ;!

Vacuum tube "valve#

"hethermionicvacuum tuediode% originall# called theleming valve%as invented # OohnAmrose leming in 1MD4 as a detector for radio aves in radio receivers% and evolved into a generalrectifier! /t consisted of an evacuated glass ul ith afilamentheated # a separate current% and ametal plate anode!"he filament emittedelectrons#thermionic emission(the ,dison effect)%discovered # "homas ,disonin 1LL4% and a positive voltage on the plate caused a current ofelectrons through the tue from filament to plate! 8ince onl# the filament produced electrons% the tueould onl# conduct current in one direction% alloing the tue to rectif# an alternating current!

;acuum diode rectifiers ere idel# used in poer supplies in vacuum tue consumer electronicproducts% such as phonographs% radios% and televisions% for e*ample theAll American iveradioreceiver% to provide the high &C plate voltage needed # other vacuum tues! -ullave- versionsith to separate plates ere popular ecause the# could e used ith a centertapped transformerto ma$e a fullave rectifier! ;acuum rectifiers ere made for ver# high voltages% such as the highvoltage poer suppl# for thecathode ra# tueoftelevisionreceivers% and the $enotron used forpoer suppl# inPra#euipment! +oever% compared to modern semiconductor diodes% vacuumrectifiers have high internal resistance due tospace chargeand therefore high voltage drops% causinghigh poer dissipation and lo efficienc#! "he# are rarel# ale to handle currents e*ceeding 25D mAoing to the limits of plate poer dissipation% and cannot e used for lo voltage applications% suchas atter# chargers! Another limitation of the vacuum tue rectifier is that the heater poer suppl#often reuires special arrangements to insulate it from the high voltages of the rectifier circuit!

http://en.wikipedia.org/wiki/Anodehttp://en.wikipedia.org/wiki/Anodehttp://en.wikipedia.org/wiki/Flame_rectificationhttp://en.wikipedia.org/wiki/Flame_rectificationhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Manitoba_Hydrohttp://en.wikipedia.org/wiki/Manitoba_Hydrohttp://en.wikipedia.org/wiki/Nelson_River_Bipolehttp://en.wikipedia.org/wiki/Nelson_River_Bipolehttp://en.wikipedia.org/wiki/Rectifier#cite_note-12http://en.wikipedia.org/wiki/Rectifier#cite_note-12http://en.wikipedia.org/wiki/General_Electrichttp://en.wikipedia.org/wiki/General_Electrichttp://en.wikipedia.org/wiki/General_Electrichttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Gas-filled_tubehttp://en.wikipedia.org/wiki/Gas-filled_tubehttp://en.wikipedia.org/wiki/Metal_rectifierhttp://en.wikipedia.org/wiki/Metal_rectifierhttp://en.wikipedia.org/wiki/Incandescent_lamphttp://en.wikipedia.org/wiki/Incandescent_lamphttp://en.wikipedia.org/wiki/Incandescent_lamphttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Thermionic_emissionhttp://en.wikipedia.org/wiki/Thermionic_emissionhttp://en.wikipedia.org/wiki/Thermionic_emissionhttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Fleming_valvehttp://en.wikipedia.org/wiki/Fleming_valvehttp://en.wikipedia.org/wiki/Fleming_valvehttp://en.wikipedia.org/wiki/Electrical_filamenthttp://en.wikipedia.org/wiki/Electrical_filamenthttp://en.wikipedia.org/wiki/Anodehttp://en.wikipedia.org/wiki/Anodehttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Thermionic_emissionhttp://en.wikipedia.org/wiki/Thermionic_emissionhttp://en.wikipedia.org/wiki/Thomas_Edisonhttp://en.wikipedia.org/wiki/Thomas_Edisonhttp://en.wikipedia.org/wiki/All_American_Fivehttp://en.wikipedia.org/wiki/All_American_Fivehttp://en.wikipedia.org/wiki/All_American_Fivehttp://en.wikipedia.org/wiki/Cathode_ray_tubehttp://en.wikipedia.org/wiki/Cathode_ray_tubehttp://en.wikipedia.org/wiki/Cathode_ray_tubehttp://en.wikipedia.org/wiki/Televisionhttp://en.wikipedia.org/wiki/Televisionhttp://en.wikipedia.org/wiki/Televisionhttp://en.wikipedia.org/wiki/X-rayhttp://en.wikipedia.org/wiki/X-rayhttp://en.wikipedia.org/wiki/Space_chargehttp://en.wikipedia.org/wiki/Space_chargehttp://en.wikipedia.org/wiki/Space_chargehttp://en.wikipedia.org/wiki/Anodehttp://en.wikipedia.org/wiki/Flame_rectificationhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Manitoba_Hydrohttp://en.wikipedia.org/wiki/Nelson_River_Bipolehttp://en.wikipedia.org/wiki/Rectifier#cite_note-12http://en.wikipedia.org/wiki/Rectifier#cite_note-sood1-13http://en.wikipedia.org/wiki/General_Electrichttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Gas-filled_tubehttp://en.wikipedia.org/wiki/Metal_rectifierhttp://en.wikipedia.org/wiki/Incandescent_lamphttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Thermionic_emissionhttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Fleming_valvehttp://en.wikipedia.org/wiki/Electrical_filamenthttp://en.wikipedia.org/wiki/Anodehttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Thermionic_emissionhttp://en.wikipedia.org/wiki/Thomas_Edisonhttp://en.wikipedia.org/wiki/All_American_Fivehttp://en.wikipedia.org/wiki/Cathode_ray_tubehttp://en.wikipedia.org/wiki/Televisionhttp://en.wikipedia.org/wiki/X-rayhttp://en.wikipedia.org/wiki/Space_charge

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/nmusical instrument amplification(especiall# for electric guitars)% the slight dela# or -sag- eteen asignal increase (for instance% hen a guitar chord is struc$ hard and fast) and the correspondingincrease in output voltage is a notale effect of tue rectification% and results incompression!"hechoice eteen tue rectification and diode rectification is a matter of taste< some amplifiers haveoth and allo the pla#er to choose!14

Solid state

"he cat.shis$er detector as the earliest t#pe of semiconductor diode! /t consisted of a cr#stal ofsome semiconductingmineral% usuall#galena(lead sulfide)% ith a light spring# ire touching itssurface! /nvented #Oagadish Chandra 0oseand developed #>! ! 'ic$ardaround 1MD6% it servedas the radio ave rectifier in the first idel# used radio receivers% calledcr#stal radios!/ts fragilit# andlimited current capailit# made it unsuitale for poer suppl# applications! /t ecame osolete around1M2D% ut later versions served as microave detectors and mi*ers inradarreceivers during orld

ar 2!

9nce common until replaced # more compact and less costl# silicon solidstate rectifiers in the1M7Ds% these units used stac$s of metal plates and too$ advantage of thesemiconductorpropertiesofseleniumor copper o*ide! 15hile selenium rectifiersere lighter in eight and used less poerthan comparale vacuum tue rectifiers% the# had the disadvantage of finite life e*pectanc#%increasing resistance ith age% and ere onl# suitale to use at lo freuencies! 0oth selenium andcopper o*ide rectifiers have somehat etter tolerance of momentar# voltage transients than siliconrectifiers!

"#picall# these rectifiers ere made up of stac$s of metal plates or ashers% held together # acentral olt% ith the numer of stac$s determined # voltage< each cell as rated for aout 2D ;! Anautomotive atter# charger rectifier might have onl# one cell= the highvoltage poer suppl# foravacuum tuemight have do?ens of stac$ed plates! Current densit# in an aircooled selenium stac$as aout 6DD mA per suare inch of active area (aout MD mA per suare centimeter)!

/n the modern orld%silicondiodes are the most idel# used rectifiers for loer voltages and poers%

and have largel# replaced earliergermaniumdiodes! or ver# high voltages and poers% the addedneed for controllailit# has in practice led to replacing simple silicon diodes ith highpoer th#ristors(see elo) and their neer activel# gatecontrolled cousins!

http://en.wikipedia.org/wiki/Instrument_amplifierhttp://en.wikipedia.org/wiki/Instrument_amplifierhttp://en.wikipedia.org/wiki/Instrument_amplifierhttp://en.wikipedia.org/wiki/Dynamic_range_compressionhttp://en.wikipedia.org/wiki/Dynamic_range_compressionhttp://en.wikipedia.org/wiki/Dynamic_range_compressionhttp://en.wikipedia.org/wiki/Rectifier#cite_note-14http://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Jagadish_Chandra_Bosehttp://en.wikipedia.org/wiki/Jagadish_Chandra_Bosehttp://en.wikipedia.org/wiki/Jagadish_Chandra_Bosehttp://en.wikipedia.org/wiki/Greenleaf_Whittier_Pickardhttp://en.wikipedia.org/wiki/Greenleaf_Whittier_Pickardhttp://en.wikipedia.org/wiki/Crystal_radiohttp://en.wikipedia.org/wiki/Crystal_radiohttp://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Seleniumhttp://en.wikipedia.org/wiki/Seleniumhttp://en.wikipedia.org/wiki/Seleniumhttp://en.wikipedia.org/wiki/Rectifier#cite_note-15http://en.wikipedia.org/wiki/Rectifier#cite_note-15http://en.wikipedia.org/wiki/Rectifier#cite_note-15http://en.wikipedia.org/wiki/Selenium_rectifierhttp://en.wikipedia.org/wiki/Selenium_rectifierhttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Instrument_amplifierhttp://en.wikipedia.org/wiki/Dynamic_range_compressionhttp://en.wikipedia.org/wiki/Rectifier#cite_note-14http://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Galenahttp://en.wikipedia.org/wiki/Jagadish_Chandra_Bosehttp://en.wikipedia.org/wiki/Greenleaf_Whittier_Pickardhttp://en.wikipedia.org/wiki/Crystal_radiohttp://en.wikipedia.org/wiki/Radarhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Seleniumhttp://en.wikipedia.org/wiki/Rectifier#cite_note-15http://en.wikipedia.org/wiki/Selenium_rectifierhttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Thyristor

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/n highpoer applications% from 1M75 to 2DDD% most mercur# valve arcrectifiers ere replaced #stac$s of ver# high poerth#ristors% silicon devices ith to e*tra la#ers of semiconductor% incomparison to a simple diode!

/n mediumpoer transmission applications% even more comple* and sophisticatedvoltage sourced

converter(;8C) silicon semiconductor rectifier s#stems% such asinsulated gate ipolar transistors(/>0")andgate turnoff th#ristors (>"9)%have made smaller high voltage &C poer transmissions#stems economical! All of these devices function as rectifiers!

As of 2DDM it as e*pected that these highpoer silicon -selfcommutating sitches%- in particular/>0"s and a variant th#ristor (related to the >"9) called theintegrated gatecommutatedth#ristor(/>C")% ould e scaledup in poer rating to the point that the# ould eventuall# replacesimple th#ristorased AC rectification s#stems for the highest poertransmission &C applications! 16

http://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Voltage_sourced_converterhttp://en.wikipedia.org/wiki/Voltage_sourced_converterhttp://en.wikipedia.org/wiki/Voltage_sourced_converterhttp://en.wikipedia.org/wiki/Voltage_sourced_converterhttp://en.wikipedia.org/wiki/IGBT_transistorhttp://en.wikipedia.org/wiki/IGBT_transistorhttp://en.wikipedia.org/wiki/IGBT_transistorhttp://en.wikipedia.org/wiki/IGBT_transistorhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Integrated_gate-commutated_thyristorhttp://en.wikipedia.org/wiki/Integrated_gate-commutated_thyristorhttp://en.wikipedia.org/wiki/Integrated_gate-commutated_thyristorhttp://en.wikipedia.org/wiki/Integrated_gate-commutated_thyristorhttp://en.wikipedia.org/wiki/Rectifier#cite_note-16http://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Voltage_sourced_converterhttp://en.wikipedia.org/wiki/Voltage_sourced_converterhttp://en.wikipedia.org/wiki/IGBT_transistorhttp://en.wikipedia.org/wiki/IGBT_transistorhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Integrated_gate-commutated_thyristorhttp://en.wikipedia.org/wiki/Integrated_gate-commutated_thyristorhttp://en.wikipedia.org/wiki/Rectifier#cite_note-16