labarai

Capacitors na ɗaya daga cikin abubuwan da aka fi amfani da su akan allon kewayawa. Yayin da adadin na'urorin lantarki (daga wayar hannu zuwa motoci) ke ci gaba da karuwa, haka ma bukatar capacitors ke karuwa. Cutar sankarau ta Covid 19 ta tarwatsa sarkar samar da kayan aikin duniya daga semiconductor zuwa abubuwan da ba a iya amfani da su ba, kuma capacitors sun kasance a takaice.
Tattaunawa kan batun capacitors ana iya juyar da su cikin sauƙi zuwa littafi ko ƙamus. Na farko, akwai nau'o'in capacitors daban-daban, irin su electrolytic capacitors, film capacitors, yumbu capacitors da sauransu. Sa'an nan, a cikin nau'i ɗaya, akwai nau'in dielectric daban-daban. Akwai kuma ajujuwa daban-daban. Dangane da tsarin jiki, akwai nau'ikan capacitor biyu na tasha da uku. Akwai kuma nau'in capacitor nau'in X2Y, wanda shine ainihin nau'in capacitors na Y wanda aka lullube cikin daya. Me game da supercapacitors? Gaskiyar ita ce, idan kun zauna kuma ku fara karanta jagororin zaɓin capacitor daga manyan masana'antun, zaku iya ciyar da ranar cikin sauƙi!
Tun da wannan labarin yana game da abubuwan yau da kullun, zan yi amfani da wata hanya dabam kamar yadda aka saba. Kamar yadda aka ambata a baya, ana iya samun jagororin zaɓin capacitor a cikin sauƙi a kan gidajen yanar gizon masu kaya 3 da 4, kuma injiniyoyin filin galibi suna iya amsa yawancin tambayoyi game da masu iya aiki. A cikin wannan labarin, ba zan sake maimaita abin da za ku iya samu akan Intanet ba, amma zan nuna yadda ake zaɓar da amfani da capacitors ta hanyar misalai masu amfani. Wasu abubuwan da ba a san su ba na zaɓin capacitor, kamar lalata ƙarfin ƙarfin, za a kuma rufe su. Bayan karanta wannan labarin, ya kamata ka sami kyakkyawar fahimtar amfani da capacitors.
Shekaru da suka gabata, lokacin da nake aiki a wani kamfani da ke kera kayan aikin lantarki, mun yi hira da injiniyan lantarki. A kan zane-zane na samfurin da ke akwai, za mu tambayi masu neman takara "Mene ne aikin haɗin wutar lantarki na DC?" da "Menene aikin yumbu capacitor dake kusa da guntu?" Muna fatan cewa madaidaicin amsar ita ce capacitor bas na DC Ana amfani dashi don ajiyar makamashi, ana amfani da capacitors na yumbu don tacewa.
Amsar "daidai" da muke nema tana nuna a zahiri cewa kowa da kowa a cikin ƙungiyar ƙira yana kallon capacitors daga hangen nesa mai sauƙi, ba daga yanayin ka'idar filin ba. Ma'anar ka'idar da'ira ba kuskure ba ce. A ƙananan mitoci (daga ƴan kHz zuwa ƴan MHz), ka'idar kewayawa na iya bayyana matsalar da kyau. Wannan saboda a ƙananan mitoci, siginar yana yawanci cikin yanayin banbantacce. Yin amfani da ka'idar kewayawa, za mu iya ganin capacitor da aka nuna a cikin Hoto 1, inda daidaitattun juriya na juriya (ESR) da kuma daidaitattun jerin inductance (ESL) suna yin canjin capacitor tare da mita.
Wannan samfurin yana bayyana cikakken aikin da'irar lokacin da aka kunna kewayawa a hankali. Duk da haka, yayin da mita ke ƙaruwa, abubuwa suna ƙara rikitarwa. A wani lokaci, ɓangaren yana fara nuna rashin daidaituwa. Lokacin da mitar ta karu, ƙirar LCR mai sauƙi tana da iyakokinta.
A yau, idan aka yi mani wannan tambayar ta hira, zan sa gilashin lura da ka'idar filina in ce duka nau'ikan capacitor na'urorin adana makamashi ne. Bambanci shi ne cewa masu amfani da wutar lantarki na iya adana makamashi fiye da capacitors na yumbu. Amma dangane da watsa makamashi, yumbu capacitors na iya watsa makamashi cikin sauri. Wannan ya bayyana dalilin da ya sa ake buƙatar sanya masu ƙarfin yumbura kusa da guntu, saboda guntu yana da mafi girma na sauyawa da saurin sauyawa idan aka kwatanta da babban wutar lantarki.
Daga wannan hangen nesa, za mu iya kawai ayyana matakan aiki guda biyu don capacitors. Daya shine yawan kuzarin da capacitor zai iya adanawa, na biyu kuma shine yadda ake saurin tura wannan makamashin. Dukansu sun dogara ne akan hanyar masana'anta na capacitor, dielectric abu, haɗi tare da capacitor, da sauransu.
Lokacin da aka rufe maɓalli a cikin kewayawa (duba hoto 2), yana nuna cewa nauyin yana buƙatar makamashi daga tushen wutar lantarki. Gudun da wannan canji ke rufewa yana ƙayyade gaggawar buƙatar makamashi. Tunda makamashi yana tafiya a saurin haske (rabin saurin haske a cikin kayan FR4), yana ɗaukar lokaci don canja wurin makamashi. Bugu da ƙari, akwai rashin daidaituwa tsakanin tushen da layin watsawa da kaya. Wannan yana nufin cewa ba za a taɓa canja wurin makamashi a cikin tafiya ɗaya ba, amma a cikin tafiye-tafiye da yawa5, wanda shine dalilin da ya sa lokacin da aka kunna sauyawa da sauri, za mu ga jinkiri da ƙara a cikin yanayin sauyawa.
Hoto 2: Yana ɗaukar lokaci kafin makamashi ya yadu a sararin samaniya; rashin daidaituwa na impedance yana haifar da tafiye-tafiye da yawa na canja wurin makamashi.
Gaskiyar cewa isar da makamashi yana ɗaukar lokaci da tafiye-tafiye da yawa yana gaya mana cewa muna buƙatar matsar da makamashin kusa da kaya, kuma muna buƙatar nemo hanyar isar da shi cikin sauri. Ana samun na farko ta hanyar rage nisa ta jiki tsakanin kaya, sauyawa da capacitor. Ana samun na ƙarshe ta hanyar tara ƙungiyar capacitors tare da mafi ƙarancin impedance.
Ka'idar filin kuma ta bayyana abin da ke haifar da hayaniyar yanayin gama gari. A taƙaice, ana haifar da hayaniyar yanayin gama gari lokacin da ba a cika buƙatun makamashin kaya yayin sauyawa ba. Sabili da haka, za a samar da makamashin da aka adana a cikin sarari tsakanin kaya da masu gudanarwa na kusa don tallafawa buƙatar mataki. Wurin da ke tsakanin kaya da masu gudanarwa na kusa shine abin da muke kira karfin karfin juna (duba hoto 2).
Muna amfani da misalan masu zuwa don nuna yadda ake amfani da masu ƙarfin lantarki, masu ƙarfin yumbura da yawa (MLCC), da masu ƙarfin fim. Ana amfani da ka'idar kewayawa da ka'idar filin don bayyana ayyukan da aka zaɓa na capacitors.
Ana amfani da capacitors na lantarki a cikin hanyar haɗin DC a matsayin babban tushen makamashi. Zaɓin capacitor electrolytic sau da yawa ya dogara da:
Don aikin EMC, mafi mahimmancin halayen capacitors sune impedance da halayen mita. Ƙarƙashin mitar da ake gudanarwa koyaushe yana dogara ne akan aikin ma'aunin mahaɗin DC.
Rashin haɗin haɗin DC ya dogara ba kawai akan ESR da ESL na capacitor ba, har ma a kan yanki na madauki na thermal, kamar yadda aka nuna a cikin Hoto 3. Babban yanki na madauki na thermal yana nufin cewa canja wurin makamashi yana ɗaukar lokaci mai tsawo, don haka aiki za a shafa.
An gina na'ura mai canzawa ta DC-DC don tabbatar da hakan. Saitin gwajin EMC na farko da aka nuna a Hoto 4 yana yin sikanin fitar da iska tsakanin 150kHz da 108MHz.
Yana da mahimmanci don tabbatar da cewa capacitors da aka yi amfani da su a cikin wannan binciken duk sun fito ne daga masana'anta guda ɗaya don kauce wa bambance-bambance a cikin halayen impedance. Lokacin sayar da capacitor akan PCB, tabbatar cewa babu dogayen jagorori, saboda wannan zai ƙara ESL na capacitor. Hoto na 5 yana nuna saitunan guda uku.
Sakamakon watsi da aka gudanar na waɗannan saiti guda uku ana nuna su a cikin Hoto na 6. Ana iya ganin cewa, idan aka kwatanta da guda ɗaya na 680 µF capacitor, 330 µF capacitors guda biyu sun cimma aikin rage amo na 6 dB a kan kewayon mitar da ya fi girma.
Daga ka'idar kewayawa, ana iya cewa ta hanyar haɗa capacitors guda biyu a layi daya, duka ESL da ESR sun ragu. Daga mahangar ka'idar filin, ba tushen makamashi ɗaya kaɗai ba ne, amma ana samar da hanyoyin makamashi guda biyu zuwa kaya iri ɗaya, yadda ya kamata yana rage lokacin watsa makamashi gabaɗaya. Koyaya, a mafi girman mitoci, bambanci tsakanin masu ƙarfin 330 µF guda biyu da capacitor 680 µF ɗaya zai ragu. Wannan saboda hayaniyar mita mai girma yana nuna rashin isassun ƙarfin amsawar mataki. Lokacin matsar da capacitor na 330 µF kusa da sauyawa, muna rage lokacin canja wurin makamashi, wanda hakan yana ƙaruwa da amsa matakin capacitor yadda ya kamata.
Sakamakon ya gaya mana darasi mai mahimmanci. Ƙara ƙarfin capacitor guda ɗaya ba zai goyi bayan matakin buƙatar ƙarin makamashi ba. Idan za ta yiwu, yi amfani da wasu ƙananan abubuwan haɗin gwiwa. Akwai kyawawan dalilai da yawa akan hakan. Na farko shine farashi. Gabaɗaya magana, don girman fakiti ɗaya, farashin capacitor yana ƙaruwa sosai tare da ƙimar ƙarfin aiki. Yin amfani da capacitor guda ɗaya na iya zama mafi tsada fiye da amfani da ƙananan capacitors da yawa. Dalili na biyu shine girman. Maƙasudin ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙirar samfur yawanci tsayin abubuwan abubuwan. Don manyan masu iya aiki, tsayin daka sau da yawa yana da girma, wanda bai dace da ƙirar samfurin ba. Dalili na uku shine aikin EMC da muka gani a cikin binciken binciken.
Wani abin da za a yi la'akari da shi lokacin amfani da capacitor na electrolytic shine cewa lokacin da kuka haɗa capacitors guda biyu a jere don raba wutar lantarki, kuna buƙatar madaidaicin resistor 6.
Kamar yadda aka ambata a baya, yumbu capacitors ƙananan na'urori ne waɗanda zasu iya samar da makamashi da sauri. Sau da yawa ana yi mani tambayar "Nawa capacitor nake buƙata?" Amsar wannan tambayar ita ce, ga yumbu capacitors, ƙimar ƙarfin ƙarfin kada ta kasance mai mahimmanci. Muhimmin abin la'akari anan shine sanin wane mitar saurin canja wurin makamashi ya ishe aikace-aikacen ku. Idan watsin da aka gudanar ya kasa a 100 MHz, to, capacitor tare da ƙaramin impedance a 100 MHz zai zama kyakkyawan zaɓi.
Wannan wani rashin fahimta ne na MLCC. Na ga injiniyoyi suna ciyar da makamashi mai yawa suna zaɓar capacitors yumbu tare da mafi ƙanƙanta ESR da ESL kafin haɗa capacitors zuwa ma'anar RF ta hanyar dogayen burbushi. Yana da kyau a ambata cewa ESL na MLCC yawanci ya fi ƙasa da inductance haɗi a kan allo. Inductance haɗin haɗin kai har yanzu shine mafi mahimmancin ma'aunin da ke shafar babban ƙarfin mitar yumbura capacitors7.
Hoto na 7 yana nuna misali mara kyau. Dogayen burbushi (tsawon inci 0.5) suna gabatar da aƙalla inductance 10nH. Sakamakon simintin ya nuna cewa impedance na capacitor ya zama mafi girma fiye da yadda ake tsammani a mitar mita (50 MHz).
Ɗaya daga cikin matsalolin da MLCCs shine cewa suna da alaƙa da tsarin inductive akan allon. Ana iya ganin wannan a misalin da aka nuna a Hoto na 8, inda amfani da 10 µF MLCC ke gabatar da sauti a kusan 300 kHz.
Kuna iya rage sauti ta hanyar zaɓar wani sashi tare da babban ESR ko kawai sanya ƙaramin ƙima (kamar 1 ohm) a cikin jerin tare da capacitor. Wannan nau'in hanyar yana amfani da abubuwan da ba su da yawa don murkushe tsarin. Wata hanya ita ce a yi amfani da wata ƙimar ƙarfin ƙarfi don matsar da resonance zuwa ƙarami ko mafi girma wurin resonance.
Ana amfani da capacitors na fim a aikace-aikace da yawa. Su ne capacitors na zaɓi don masu canza DC-DC masu ƙarfi kuma ana amfani da su azaman masu tacewa na EMI a cikin layukan wuta (AC da DC) da kuma daidaita yanayin tacewa na gama gari. Mun dauki X capacitor a matsayin misali don kwatanta wasu mahimman abubuwan amfani da capacitors na fim.
Idan abin da ya faru na karuwa ya faru, yana taimakawa wajen iyakance ƙarancin wutar lantarki akan layi, don haka yawanci ana amfani da shi tare da mai hana wutar lantarki mai wucewa (TVS) ko varistor oxide (MOV).
Wataƙila kun riga kun san duk waɗannan, amma kun san cewa ƙimar ƙarfin ƙarfin ƙarfin X capacitor na iya raguwa sosai tare da shekaru masu amfani? Wannan gaskiya ne musamman idan ana amfani da capacitor a cikin yanayi mai laushi. Na ga darajar capacitor na X capacitor kawai ya ragu zuwa kashi kaɗan na ƙimar darajarsa a cikin shekara ɗaya ko biyu, don haka tsarin da aka tsara shi da farko tare da capacitor X ya rasa duk kariyar da capacitor na gaba zai iya samu.
To, me ya faru? Iska mai danshi na iya zubowa cikin capacitor, sama da waya da tsakanin akwatin da mahallin tukunyar epoxy. Aluminum metallization na iya zama oxidized. Alumina ne mai kyau lantarki insulator, don haka rage capacitance. Wannan matsala ce da duk masu karfin fim za su ci karo da su. Batun da nake magana akai shine kaurin fim. Mashahuran samfuran capacitor suna amfani da fina-finai masu kauri, wanda ke haifar da manyan capacitors fiye da sauran samfuran. Fim ɗin da ya fi ƙanƙanta yana sa capacitor ya yi ƙasa da ƙarfi don yin lodi (voltage, halin yanzu, ko zafin jiki), kuma da wuya ya warke da kansa.
Idan X capacitor ba a haɗa shi ta dindindin zuwa wutar lantarki ba, to ba kwa buƙatar damuwa. Alal misali, don samfurin da ke da matsananciyar sauyawa tsakanin wutar lantarki da capacitor, girman yana iya zama mafi mahimmanci fiye da rayuwa, sa'an nan kuma zaka iya zaɓar capacitor na bakin ciki.
Koyaya, idan capacitor yana da alaƙa na dindindin zuwa tushen wutar lantarki, dole ne ya zama abin dogaro sosai. A oxidation na capacitors ba makawa. Idan capacitor epoxy abu yana da inganci mai kyau kuma capacitor ba sau da yawa yana fallasa zuwa matsanancin yanayin zafi, raguwar darajar ya kamata ya zama kaɗan.
A cikin wannan labarin, da farko gabatar da filin ka'idar view of capacitors. Misalai masu aiki da sakamakon kwaikwaiyo suna nuna yadda ake zaɓar da amfani da mafi yawan nau'ikan capacitor. Da fatan wannan bayanin zai iya taimaka muku fahimtar rawar capacitors a cikin ƙirar lantarki da EMC sosai.
Dokta Min Zhang shi ne wanda ya kafa kuma babban mai ba da shawara na EMC na Mach One Design Ltd, wani kamfanin injiniya na Birtaniya wanda ya ƙware a cikin tuntuɓar EMC, warware matsala da horarwa. Ilminsa mai zurfi a cikin na'urorin lantarki, na'urorin lantarki na dijital, injina da ƙirar samfura sun amfana da kamfanoni a duniya.
In Compliance shine babban tushen labarai, bayanai, ilimi da kwarjini ga ƙwararrun injiniyan lantarki da na lantarki.
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