Izintambo zebhodi lesifunda eliphrintiwe (PCB) zidlala indima ebalulekile kumasekhethi anesivinini esikhulu, kodwa ngokuvamile kuba ngesinye sezinyathelo zokugcina enqubweni yokuklama isifunda. Kunezinkinga eziningi ngezintambo ze-PCB ezinesivinini esikhulu, futhi kubhalwe izincwadi eziningi ngalesi sihloko. Lesi sihloko sidingida ngokuyinhloko izintambo zamasekhethi anesivinini esikhulu ngokombono ongokoqobo. Inhloso enkulu ukusiza abasebenzisi abasha ukuthi banake izindaba eziningi ezahlukene ezidinga ukucatshangelwa lapho kwakhiwa izakhiwo zesekethe ye-PCB enesivinini esikhulu. Enye inhloso ukuhlinzeka ngezinto zokubuyekeza kumakhasimende angazange azithinti izintambo ze-PCB isikhathi eside. Ngenxa yesakhiwo esilinganiselwe, lesi sihloko asikwazi ukuxoxa ngazo zonke izinkinga ngokuningiliziwe, kodwa sizoxoxa ngezingxenye ezibalulekile ezinomthelela omkhulu ekuthuthukiseni ukusebenza kwesifunda, ukunciphisa isikhathi sokuklama, nokulondoloza isikhathi sokuguqulwa.
Nakuba okugxilwe kakhulu lapha kumasekhethi ahlobene nama-amplifiers asebenza ngesivinini esiphezulu, izinkinga nezindlela okuxoxwe ngazo lapha ngokuvamile zisebenza kuzintambo ezisetshenziswa kwezinye izifunda ze-analog ezinesivinini esikhulu. Uma i-amplifier yokusebenza isebenza kubhendi yefrikhwensi yomsakazo (RF) ephezulu kakhulu, ukusebenza kwesekhethi kuncike kakhulu ekuhlelweni kwe-PCB. Imiklamo yesekethe esebenza kahle kakhulu ebukeka kahle "emidwebeni" ingathola ukusebenza okuvamile kuphela uma ithinteka ngokunganaki ngesikhathi sezintambo. Ukucabangela kusengaphambili nokunaka imininingwane ebalulekile kuyo yonke inqubo yezintambo kuzosiza ukuqinisekisa ukusebenza kwesifunda okulindelekile.
Umdwebo wohlelo
Nakuba isikimu esihle singeke siqinisekise izintambo ezinhle, izintambo ezinhle ziqala ngohlelo oluhle. Cabanga ngokucophelela lapho udweba i-schematic, futhi kufanele ucabangele ukugeleza kwesiginali yesifunda sonke. Uma kunokugeleza kwesiginali evamile futhi ezinzile ukusuka kwesokunxele kuye kwesokudla kuhlelo, kufanele kube nokugeleza kwesignali okuhle okufanayo ku-PCB. Nikeza ulwazi oluwusizo oluningi ngangokunokwenzeka kuhlelo. Ngenxa yokuthi ngezinye izikhathi unjiniyela womklamo wesifunda akekho, amakhasimende azosicela ukuthi sisize ukuxazulula inkinga yesifunda, abaklami, ochwepheshe kanye nonjiniyela abenza lo msebenzi bazobonga kakhulu, kuhlanganise nathi.
Ngokungeziwe kuzihlonzi ezijwayelekile zereferensi, ukusetshenziswa kwamandla, nokubekezelela iphutha, yiluphi ulwazi okufanele lunikezwe kuhlelo? Nazi ezinye iziphakamiso zokuguqula ama-schematics ajwayelekile abe ama-schematics ekilasi lokuqala. Engeza ama-waveforms, ulwazi lwemishini mayelana negobolondo, ubude bemigqa ephrintiwe, izindawo ezingenalutho; khombisa ukuthi yiziphi izingxenye ezidinga ukubekwa ku-PCB; nikeza imininingwane yokulungisa, izilinganiso zenani lengxenye, ulwazi lokunqanyulwa kokushisa, lawula imigqa ephrintiwe ye-impedance, amazwana, namasekhethi amafushane Incazelo yesenzo... (kanye nokunye).
Ungakholwa muntu
Uma ungaklami izintambo ngokwakho, qiniseka ukuthi uvumela isikhathi esanele sokuhlola ngokucophelela umklamo womuntu ofaka izintambo. Ukuvimbela okuncane kuwufanele izikhathi eziyikhulu ikhambi kuleli phuzu. Ungalindeli ukuthi umuntu ofaka izintambo aqonde imibono yakho. Umbono wakho nesiqondiso yikona okubaluleke kakhulu ezigabeni zokuqala zenqubo yokuklama izintambo. Ulwazi olwengeziwe ongalunikeza, futhi uma ungenelela kakhulu kuyo yonke inqubo yokufaka izintambo, kuzoba ngcono i-PCB ewumphumela. Setha iphoyinti lokuphothula okuvivinyayo lokuhlola okusheshayo konjiniyela wezintambo ngokuya ngombiko wokuqhubeka kwezintambo owufunayo. Le ndlela “yeluphu evaliwe” ivimbela izintambo ukuthi zingaduki, ngaleyo ndlela kunciphisa amathuba okusetshenzwa kabusha.
Imiyalo okufanele inikezwe unjiniyela wokufaka izintambo ihlanganisa: incazelo emfushane yomsebenzi wesekethe, umdwebo wohlelo lwe-PCB okhombisa indawo yokufaka nokuphumayo, imininingwane yokupakishwa kwe-PCB (isibonelo, ukuthi ibhodi liwugqinsi kangakanani, zingaki izendlalelo kukhona, kanye nolwazi oluningiliziwe mayelana nongqimba lwesignali ngayinye kanye nomsebenzi wendiza yaphansi Ukusetshenziswa kwamandla, ucingo oluphansi, isignali ye-analog, isignali yedijithali nesiginali ye-RF); yiziphi izimpawu ezidingekayo kungqimba ngalunye; zidinga ukubekwa kwezingxenye ezibalulekile; indawo eqondile yezingxenye ze-bypass; yimiphi imigqa ephrintiwe ebalulekile; imiphi imigqa edinga ukulawula imigqa ephrintiwe ye-impedance; Imiphi imigqa edinga ukufanisa ubude; ubukhulu bezingxenye; yimiphi imigqa ephrintiwe edinga ukuba kude (noma isondelene) nenye; yimiphi imigqa edinga ukuba kude (noma isondele) komunye nomunye; yiziphi izingxenye ezidinga ukuba kude (noma zisondele) komunye nomunye; yiziphi izingxenye ezidinga ukubekwa Phezu kwe-PCB, yiziphi ezibekwe ngezansi. Ungalokothi ukhononde ngokuthi kunolwazi oluningi kwabanye—luncane kakhulu? Ingabe kuningi kakhulu? Ungenzi.
Okuhlangenwe nakho kokufunda: Cishe eminyakeni eyi-10 edlule, ngaklama ibhodi lesifunda le-multilayer surface Mount-kunezingxenye ezinhlangothini zombili zebhodi. Sebenzisa izikulufu eziningi ukuze ulungise ibhodi egobolondweni le-aluminium ehlanganiswe ngegolide (ngoba kunezinkomba eziqinile zokulwa nokudlidliza). Izikhonkwane ezihlinzeka ngokudla okuchema zidlula ebhodini. Le phinikhodi ixhunywe ku-PCB ngezintambo zokusoda. Lena idivayisi eyinkimbinkimbi kakhulu. Ezinye izingxenye ebhodini zisetshenziselwa ukusetha ukuhlolwa (SAT). Kodwa ngiyichaze ngokucacile indawo yalezi zingxenye. Ungaqagela ukuthi lezi zingxenye zifakwe kuphi? Ngendlela, ngaphansi kwebhodi. Lapho onjiniyela bomkhiqizo kanye nochwepheshe kufanele bahlukanise yonke idivayisi futhi baphinde bayihlanganise ngemva kokuqeda izilungiselelo, babonakala bengajabule neze. Angiphindanga ngilenze leli phutha kusukela lapho.
Isikhundla
Njengaku-PCB, indawo iyikho konke. Lapho ungabeka khona isekethe ku-PCB, lapho ungafaka khona izingxenye zayo ezithile zesifunda, futhi yiziphi ezinye izifunda eziseduze, zonke ezibaluleke kakhulu.
Imvamisa, izindawo zokufakwayo, okukhiphayo, kanye nokuphakelwa kwamandla zinqunywa kusengaphambili, kodwa isifunda esiphakathi kwakho sidinga “ukudlala ubuhlakani bazo.” Yingakho ukunaka imininingwane yezintambo kuzoletha izinzuzo ezinkulu. Qala ngendawo yezingxenye ezibalulekile futhi ucabangele isekethe ethile nayo yonke i-PCB. Ukucacisa indawo yezingxenye ezibalulekile nezindlela zesignali kusukela ekuqaleni kusiza ukuqinisekisa ukuthi umklamo uhlangabezana nemigomo yomsebenzi olindelekile. Ukuthola idizayini efanele okokuqala kunganciphisa izindleko nengcindezi-futhi kunciphise umjikelezo wokuthuthukiswa.
Amandla okudlula
Ukweqa ukunikezwa kwamandla ohlangothini lwamandla we-amplifier ukuze kwehliswe umsindo kuyisici esibaluleke kakhulu enqubweni yokuklama ye-PCB-okuhlanganisa ama-amplifiers asebenza ngesivinini esiphezulu noma amanye amasekhethi anesivinini esikhulu. Kunezindlela ezimbili zokucushwa ezijwayelekile zokudlula ama-amplifiers asebenza ngesivinini esikhulu.
Ukugxilisa indawo yokugcina amandla: Le ndlela iphumelela kakhulu ezimweni eziningi, isebenzisa ama-capacitor amaningi ahambisanayo ukuze igxilise iphinikhodi yokuphakela amandla yeamplifier yokusebenza. Ngokuvamile, ama-capacitor amabili ahambisanayo anele-kodwa ukwengeza ama-parallel capacitor kungase kuzuze amanye amasekhethi.
Ukuxhumeka okuhambisanayo kwama-capacitor anamanani ahlukene e-capacitance kusiza ekuqinisekiseni ukuthi ukuncishiswa okuphansi okushintshayo kwamanje (AC) kungabonwa kuphinikhodi yokunikezela amandla phezu kwebhendi yefrikhwensi ebanzi. Lokhu kubaluleke kakhulu emazingeni okunciphisa amandla e-operational amplifier power rejection ratio (PSR). Le capacitor isiza ukunxephezela i-PSR encishisiwe ye-amplifier. Ukugcina indlela ephansi ye-impedance ephansi kububanzi be-octave eyishumi kuzosiza ukuqinisekisa ukuthi umsindo oyingozi awukwazi ukungena ku-op amp. Umfanekiso we-1 ubonisa izinzuzo zokusebenzisa ama-capacitor amaningi ngokuhambisana. Emaza aphansi, ama-capacitor amakhulu ahlinzeka ngendlela ephansi ye-impedance. Kodwa uma imvamisa ifinyelela imvamisa yabo ye-resonant, i-capacitance ye-capacitor izoba buthaka futhi kancane kancane ibonakale i-inductive. Yingakho kubalulekile ukusebenzisa ama-capacitor amaningi: lapho impendulo yemvamisa ye-capacitor eyodwa iqala ukwehla, impendulo yemvamisa yenye i-capacitor iqala ukusebenza, ngakho-ke ingagcina i-AC impedance ephansi kakhulu ezindaweni eziningi ze-octave eziyishumi.
Qala ngokuqondile ngezikhonkwane zokuhlinzeka amandla we-op amp; i-capacitor enamandla amancane kakhulu kanye nobukhulu obuncane bomzimba kufanele bubekwe ohlangothini olufanayo lwe-PCB njenge-op amp-futhi eduze ngangokunokwenzeka ku-amplifier. Itheminali yaphansi ye-capacitor kufanele ixhunywe ngokuqondile endizeni yaphansi ngephini elifushane kakhulu noma intambo ephrintiwe. Ukuxhumana okungenhla komhlaba kufanele kusondele ngangokunokwenzeka kutheminali yokulayisha ye-amplifier ukuze kuncishiswe ukuphazamiseka phakathi kwetheminali yamandla kanye netheminali yaphansi.
Le nqubo kufanele iphindwe kuma-capacitor anevelu enkulu elandelayo ye-capacitance. Kungcono kakhulu ukuqala ngenani elincane le-capacitance elingu-0.01 µF bese ubeka i-electrolytic capacitor engu-2.2 µF (noma enkulu) enochungechunge olulinganayo ukumelana (ESR) eduze nayo. I-capacitor engu-0.01 µF enosayizi wekesi elingu-0508 inokufakwa kochungechunge oluphansi kakhulu nokusebenza okuhle kakhulu kwefrikhwensi ephezulu.
Ukunikezwa kwamandla ekunikezeni amandla: Enye indlela yokumisa isebenzisa i-bypass capacitor eyodwa noma ngaphezulu exhunywe kuwo wonke amatheminali okuphakela amandla okuhle nokubi we-amplifier yokusebenza. Le ndlela ivame ukusetshenziswa uma kunzima ukumisa ama-capacitor amane kumjikelezo. Ububi bayo ukuthi usayizi wecala le-capacitor ungakhuphuka ngenxa yokuthi i-voltage kuyo yonke i-capacitor iphindwe kabili inani le-voltage endleleni yokuphambuka okukodwa. Ukwandisa i-voltage kudinga ukukhulisa i-voltage elinganiselwe yokuwohloka kwedivayisi, okungukuthi, ukwandisa usayizi wezindlu. Kodwa-ke, le ndlela ingathuthukisa i-PSR nokusebenza okuhlanekezela.
Ngenxa yokuthi isifunda ngasinye kanye nezintambo zihlukile, ukucushwa, inombolo kanye nenani le-capacitance yama-capacitors kufanele kunqunywe ngokuvumelana nezidingo zesifunda sangempela.