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I-Capacitors yenye yezona zinto zisetyenziswa ngokuqhelekileyo kwiibhodi zesekethe.Njengoko inani lezixhobo zombane (ukusuka kwiifowuni eziphathwayo ukuya kwiimoto) liqhubeka nokukhula, ngokunjalo imfuno ye-capacitors. ukuya kumacandelo okwenziwa, kunye nee-capacitors bezinqongophele1.
Iingxoxo ngesihloko se-capacitors ziyakwazi ukuguqulwa ngokulula zibe yincwadi okanye isichazi-magama.Okokuqala, kukho iintlobo ezahlukeneyo ze-capacitors, ezifana ne-electrolytic capacitors, i-film capacitors, i-ceramic capacitors kunye nokunye.Emva koko, kuhlobo olufanayo, kukho ezahlukeneyo ezahlukeneyo. izixhobo ze-dielectric.Kukho kwakhona iiklasi ezahlukeneyo.Ngokubhekiselele kwisakhiwo somzimba, kukho iindidi ezimbini ze-terminal kunye ne-terminal ye-terminal capacitor.Kukho kwakhona uhlobo lwe-X2Y uhlobo lwe-capacitor, eyona nto i-Y capacitors efakwe kwelinye.Kuthekani malunga ne-supercapacitors ?Inyani yile, ukuba uhlala phantsi kwaye uqale ukufunda izikhokelo zokukhetha i-capacitor ezivela kubavelisi abakhulu, unokuchitha imini ngokulula!
Ekubeni eli nqaku limalunga neziseko ezisisiseko, ndiya kusebenzisa indlela eyahlukileyo njengesiqhelo.Njengoko kukhankanywe ngaphambili, izikhokelo zokukhetha i-capacitor zinokufumaneka ngokulula kwiiwebhusayithi zababoneleli be-3 kunye ne-4, kwaye iinjineli zentsimi zidla ngokuphendula imibuzo emininzi malunga ne-capacitors.Kweli nqaku, Andiyi kuphinda into ongayifumana kwi-Intanethi, kodwa iya kubonisa indlela yokukhetha nokusebenzisa i-capacitors ngokusebenzisa imizekelo ebonakalayo.Eminye imiba engaziwayo yokukhethwa kwe-capacitor, njengokuthotywa kwe-capacitance, nayo iya kugutyungelwa.Emva kokufunda eli nqaku, wena kufuneka ube nokuqonda kakuhle kokusetyenziswa kwee-capacitors.
Kwiminyaka eyadlulayo, xa ndandisebenza kwinkampani eyenza izixhobo ze-elektroniki, sasinombuzo wodliwano-ndlebe kwinjineli ye-elektroniki yamandla. capacitor?” kwaye "Yintoni umsebenzi we-ceramic capacitor ecaleni kwetshiphu?" Siyathemba ukuba impendulo echanekileyo yi-DC bus capacitor Isetyenziselwa ukugcina amandla, i-ceramic capacitors isetyenziselwa ukucoca.
Impendulo "echanekileyo" esiyifunayo ngokwenene ibonisa ukuba wonke umntu okwiqela loyilo ujonga i-capacitors ukusuka kumbono wesekethe olula, kungekhona kwimbono ye-theory yentsimi.Imbono ye-circuit theory ayiphosakanga.Kwi-frequencies ephantsi (ukusuka kwi-kHz embalwa ukuya kwi-MHz embalwa), ithiyori yesekethe idla ngokuchaza ingxaki kakuhle.Oku kungenxa yokuba kwiifrikhwensi ezisezantsi, umqondiso ikakhulu ukwimowudi yokwahluka.Usebenzisa ithiyori yesekethe, sinokubona i-capacitor eboniswe kuMfanekiso 1, apho ukuxhathisa okulinganayo kochungechunge ( I-ESR) kunye ne-series series inductance (ESL) yenza i-impedance ye-capacitor itshintshe ngokuphindaphindiweyo.
Lo mzekelo uchaza ngokupheleleyo ukusebenza kwesekethe xa isiphaluka sitshintshelwa kancinci.Nangona kunjalo, njengoko isantya sinyuka, izinto ziba nzima ngakumbi.Ngexesha elithile, icandelo liqala ukubonisa ukungahambelani.Xa i-frequency inyuka, imodeli ye-LCR elula inemida yayo.
Namhlanje, ukuba ndibuzwa umbuzo ofanayo wodliwano-ndlebe, ndiza kunxiba iiglasi zam iiglasi zokujonga i-theory yentsimi kwaye ndithi zombini iintlobo ze-capacitor ziyizixhobo zokugcina amandla.Ukwahlukana kukuba i-electrolytic capacitors inokugcina amandla angaphezu kwe-ceramic capacitors.Kodwa ngokubhekiselele kumbane wokuhambisa amandla. , i-ceramic capacitors inokuhambisa amandla ngokukhawuleza.Oku kuchaza ukuba kutheni i-ceramic capacitors kufuneka ibekwe ecaleni kwe-chip, kuba i-chip ine-frequency ephezulu yokutshintsha kunye nesantya sokutshintsha xa kuthelekiswa nombane omkhulu wesiphaluka.
Ukusuka kulo mbono, sinokuchaza nje imigangatho emibini yokusebenza kwee-capacitors.Enye kukuba amandla angakanani i-capacitor enokuyigcina, kwaye enye yindlela ekhawuleza ngayo ukudluliselwa kwamandla.Zombini zixhomekeke kwindlela yokuvelisa i-capacitor, i-dielectric material, uxhulumaniso kunye ne-capacitor, njalo njalo.
Xa ukutshintshwa kwisekethe kuvaliwe (jonga uMzobo 2), kubonisa ukuba umthwalo ufuna amandla avela kumthombo wamandla.Isantya apho olu tshintsho luvala khona ukukhawuleza kwemfuno yamandla.Njengoko amandla ahamba ngesantya sokukhanya (isiqingatha). isantya sokukhanya kwizinto ze-FR4), kuthatha ixesha lokudlulisa amandla.Ngaphezu koko, kukho ukungahambelani kwe-impedance phakathi komthombo kunye nomgca wokuhambisa kunye nomthwalo.Oku kuthetha ukuba amandla angeke adluliselwe kwelinye uhambo, kodwa kwiindawo ezininzi. uhambo olujikelezayo5, yiyo loo nto xa utshintsho lutshintsha ngokukhawuleza, sibona ukulibaziseka kunye nokukhala kwi-wave wave wave.
Umfanekiso 2: Kuthatha ixesha ukuze amandla asasazeke esithubeni; ukungahambelani kwe-impedance kubangela iihambo ezininzi ezijikelezayo zokudluliselwa kwamandla.
Inyaniso yokuba ukuhanjiswa kwamandla kuthatha ixesha kunye neehambo ezininzi ezijikelezayo zisixelela ukuba kufuneka sibeke umthombo wamandla ngokusondeleyo kumthwalo ngokusemandleni, kwaye kufuneka sifumane indlela yokudlulisa amandla ngokukhawuleza.Eyokuqala idla ngokufezekiswa ngokunciphisa umzimba. umgama phakathi komthwalo, utshintshe kunye ne-capacitor.Okugqibela kufezekiswa ngokuqokelela iqela le-capacitors kunye neyona impedance encinci.
Ithiyori yendawo iphinda ichaze oko kubangela ingxolo yemowudi eqhelekileyo.Ngokufutshane, ingxolo yemowudi eqhelekileyo yenziwa xa imfuno yamandla yomthwalo ingafezekiswanga ngexesha lokutshintsha.Ngoko ke, amandla agcinwe kwindawo phakathi komthwalo kunye nabaqhubi abasondeleyo baya kunikwa ukuxhasa. imfuno yesinyathelo.Isithuba phakathi komthwalo kunye nabaqhubi abasondeleyo yinto esiyibiza ngokuba yi-parasitic / mutual capacitance (jonga uMzobo 2).
Sisebenzisa le mizekelo ilandelayo ukubonisa indlela yokusebenzisa i-electrolytic capacitors, i-multilayer ceramic capacitors (MLCC), kunye nefilimu capacitors.Zombini i-circuit kunye ne-field theory zisetyenziselwa ukuchaza ukusebenza kwee-capacitors ezikhethiweyo.
Ii-electrolytic capacitors zisetyenziswa ikakhulu kwi-DC link njengowona mthombo wamandla.Ukhetho lwe-electrolytic capacitor luhlala luxhomekeke kwi:
Ukusebenza kwe-EMC, iimpawu ezibaluleke kakhulu ze-capacitors ziyi-impedance kunye neempawu ze-frequency.Ukukhutshwa kwe-low-frequency eyenziwa rhoqo kuxhomekeke ekusebenzeni kwe-DC link capacitor.
I-impedance ye-DC link ayixhomekanga kuphela kwi-ESR kunye ne-ESL ye-capacitor, kodwa nakwindawo ye-thermal loop, njengoko kubonisiwe kuMfanekiso 3. Indawo enkulu ye-thermal loop ithetha ukuba ukuhanjiswa kwamandla kuthatha ixesha elide, ngoko ukusebenza iya kuchaphazeleka.
Isiguquli se-DC-DC esisezantsi sakhiwe ukubonisa oku.Ukusetwa kovavanyo lwe-EMC kwangaphambili oluboniswe kuMzobo 4 lwenza iscan ephumayo eqhutywayo phakathi kwe-150kHz kunye ne-108MHz.
Kubalulekile ukuqinisekisa ukuba i-capacitors esetyenziswe kulo mzekelo wesifundo zonke zivela kumvelisi ofanayo ukuphepha ukungafani kweempawu ze-impedance.Xa uthengisa i-capacitor kwi-PCB, qiniseka ukuba akukho zikhokelo ezide, njengoko oku kuya kwandisa i-ESL i-capacitor.Umfanekiso 5 ubonisa ulungelelwaniso oluthathu.
Iziphumo ezikhutshwayo eziqhutywayo zolu lungelelwaniso zintathu zibonisiwe kuMfanekiso 6.Kungabonwa ukuba, xa kuthelekiswa ne-680 µF capacitor enye, ii-capacitor ezimbini ze-330 µF zifezekisa ukusebenza kokunciphisa ingxolo ye-6 dB kuluhlu lwamaza obuninzi obubanzi.
Ukususela kwi-theory yesekethe, kunokuthiwa ngokudibanisa i-capacitors ezimbini ngokufanayo, zombini i-ESL kunye ne-ESR ziyi-halved.Kusuka kwimbono ye-theory yentsimi, akukho mthombo wamandla omnye kuphela, kodwa imithombo emibini yamandla inikezelwa kumthwalo ofanayo. , ngokufanelekileyo ukunciphisa ixesha lokuhanjiswa kwamandla.Nangona kunjalo, kwiifrikhwensi eziphezulu, umahluko phakathi kwee-capacitor ezimbini ze-330 µF kunye ne-680 µF capacitor enye iya kucutheka. Oku kungenxa yokuba ingxolo ephezulu ibonisa ukungonelanga kwempendulo yamandla.Xa uhambisa i-330 µF capacitor kufutshane ne umtshintshi, sinciphisa ixesha lokudlulisa amandla, okwandisa ngokufanelekileyo impendulo yesinyathelo se-capacitor.
Isiphumo sisixelela isifundo esibaluleke kakhulu.Ukunyusa umthamo we-capacitor eyodwa ngokuqhelekileyo akuyi kuxhasa imfuno yesinyathelo samandla amaninzi.Ukuba kunokwenzeka, sebenzisa ezinye iinqununu ezincinci ze-capacitive.Kukho izizathu ezininzi ezifanelekileyo zoku.Eyokuqala yindleko.Ngokubanzi ukuthetha, ubungakanani bepakethe efanayo, ixabiso le-capacitor linyuka ngokukhawuleza kunye nexabiso le-capacitance.Ukusebenzisa i-capacitor enye ingaba yindleko kunokusebenzisa i-capacitor encinci. yamacandelo.Ii-capacitors zomthamo omkhulu, ukuphakama kudla ngokuba kukhulu kakhulu kuyilo lwemveliso.Isizathu sesithathu yintsebenzo ye-EMC esiyibonile kwimeko yokufunda.
Enye into ekufuneka uyiqwalasele xa usebenzisa i-electrolytic capacitor kukuba xa uqhagamshela ii-capacitors ezimbini kuthotho ukwabelana nge-voltage, uya kufuna i-bancing resistor 6.
Njengoko kukhankanyiwe ngaphambili, i-ceramic capacitors zixhobo ezincinci ezinokunika amandla ngokukhawuleza.Ndihlala ndibuzwa umbuzo othi "Ndiyidinga kangakanani i-capacitor?"Impendulo yalo mbuzo kukuba i-ceramic capacitors, ixabiso le-capacitance akufanele libe libaluleke kangako. Ingqwalasela ebalulekileyo apha kukufumanisa ukuba yeyiphi isantya sogqithiso lwamandla esaneleyo kwisicelo sakho.Ukuba ukukhutshwa okuqhutywayo akuphumeleli kwi-100 MHz, ngoko ke i-capacitor ene-impedance encinci kwi-100 MHz iya kuba yinto efanelekileyo.
Le yenye ukungaqondi kakuhle kwe-MLCC. Ndibone iinjineli zichitha amandla amaninzi zikhetha i-ceramic capacitors ene-ESR ephantsi kunye ne-ESL ngaphambi kokuqhagamshela i-capacitors kwindawo yesalathiso ye-RF ngokusebenzisa imikhondo emide.Kufanelekile ukukhankanya ukuba i-ESL ye-MLCC ihlala ininzi. ngaphantsi kwe-inductance yokudibanisa ebhodini.I-inductance yokudibanisa iseyona parameter ibaluleke kakhulu echaphazela i-impedance ephezulu ye-ceramic capacitors7.
Umzobo we-7 ubonisa umzekelo ombi.Umkhondo omde (i-0.5 intshi ubude) ukwazisa ubuncinci be-10nH inductance.Isiphumo sokulinganisa sibonisa ukuba i-impedance ye-capacitor iba phezulu kakhulu kunokuba ilindeleke kwi-frequency point (50 MHz).
Enye yeengxaki ngee-MLCCs kukuba zikholisa ukunxulumana nolwakhiwo lwe-inductive ebhodini. Oku kunokubonwa kumzekelo oboniswe kuMfanekiso 8, apho ukusetyenziswa kwe-10 µF MLCC kwazisa iresonance malunga ne-300 kHz.
Unokunciphisa i-resonance ngokukhetha icandelo nge-ESR enkulu okanye ukubeka nje i-resistor encinci yexabiso (njenge-1 ohm) kwichungechunge kunye ne-capacitor.Olu hlobo lwendlela lusebenzisa amacandelo alahlekileyo ukucinezela inkqubo.Enye indlela kukusebenzisa enye i-capacitance ixabiso lokuhambisa i-resonance kwindawo esezantsi okanye ephezulu ye-resonance.
I-Film capacitors isetyenziswa kwii-applications ezininzi.Ziyi-capacitors ezikhethiweyo zamandla aphezulu e-DC-DC converters kwaye zisetyenziswa njengezihluzo zokunciphisa i-EMI kuzo zonke iintambo zamandla (AC kunye ne-DC) kunye nokucwangciswa kwemodi eqhelekileyo.Sithatha i-X capacitor njenge umzekelo wokubonisa ezinye zeengongoma eziphambili zokusebenzisa i-filimi capacitors.
Ukuba isiganeko sotyando senzeka, kunceda ukunciphisa uxinzelelo lombane oluphezulu kumgca, ngoko ke ngokuqhelekileyo lusetyenziswa kunye ne-transient voltage suppressor (TVS) okanye i-metal oxide varistor (MOV).
Usenokuba uyazi konke oku, kodwa ngaba uyazi ukuba ixabiso le-capacitance ye-X capacitor lingancitshiswa kakhulu ngeminyaka yokusetyenziswa? Oku kuyinyani ngokukodwa ukuba i-capacitor isetyenziswe kwindawo emanzi.Ndiyibonile ixabiso le-capacitance i-X capacitor yehla kuphela kwipesenti ezimbalwa zexabiso layo elilinganisiweyo phakathi konyaka okanye emibini, ngoko inkqubo eyilwe ekuqaleni kunye ne-X capacitor ilahlekelwe lukhuseleko olunokuthi lube nalo ngaphambili.
Ke, kwenzeke ntoni?Umoya wokufuma unokuvuza kwi-capacitor, phezulu ucingo naphakathi kwebhokisi kunye ne-epoxy potting compound.I-aluminium metallization ingaba yi-oxidized.I-Alumina yinto efanelekileyo yombane, ngaloo ndlela inciphisa amandla.Le yingxaki yokuba zonke ii-capacitors zefilimu ziya kuhlangabezana.Umba endithetha ngawo bubunzima befilimu.Iimpawu ze-capacitor ezihloniphekileyo zisebenzisa iifilimu ezityebileyo, ezibangela ukuba i-capacitor enkulu kunezinye iimpawu.Ifilimu encinci yenza i-capacitor ingabi namandla okugqithisa (i-voltage, yangoku, okanye iqondo lokushisa), kwaye akunakwenzeka ukuba iziphilise ngokwayo.
Ukuba i-X capacitor ayixhunyiwe ngokusisigxina kunikezelo lwamandla, ngoko akudingeki ukuba ukhathazeke.Ngokomzekelo, kwimveliso enokutshintsha okunzima phakathi kombane kunye ne-capacitor, ubukhulu bunokubaluleka kunobomi, kwaye emva koko unokukhetha i-capacitor encinci.
Nangona kunjalo, ukuba i-capacitor ixhunywe ngokusisigxina kumthombo wamandla, kufuneka ithembeke kakhulu.I-oxidation ye-capacitors ayinakuphepheka.Ukuba i-capacitor epoxy material inomgangatho omhle kwaye i-capacitor ayisoloko ibonakaliswe kumaqondo okushisa aphezulu, ukuhla ixabiso kufuneka libencinci.
Kule nqaku, kuqala ukwazisa imbono ye-theory ye-field of capacitors.Imizekelo esebenzayo kunye neziphumo zokulinganisa zibonisa indlela yokukhetha nokusebenzisa iintlobo ze-capacitor eziqhelekileyo.Ithemba ukuba olu lwazi lunokukunceda uqonde indima ye-capacitors kwi-electronic and EMC design ngokubanzi.
UGqr. Min Zhang ungumseki kunye nomcebisi oyintloko we-EMC ye-Mach One Design Ltd, inkampani yobunjineli yase-UK egxile kwi-EMC Consulting, ukulungisa iingxaki kunye noqeqesho.Ulwazi lwakhe olunzulu kumbane we-elektroniki, i-elektroniki yedijithali, iimoto kunye noyilo lwemveliso luye lwazuza. iinkampani kwihlabathi jikelele.
Ukuthobela ngowona mthombo weendaba, ulwazi, imfundo kunye nenkuthazo yeengcali zobunjineli bombane kunye ne-elektroniki.
I-Aerospace Automotive Communications Consumer Electronics Education Amandla kunye ne-Power Industry Information Technology Technology kwi-Meditary Medical and National Defense