Lub input Circuit Court ntawm tawm fais fab mov yog ib qho tseem ceeb ntawm Circuit Court ntawm switching fais fab mov. Yuav ua li cas xam thiab xaiv qhov tsis kam thiab capacitance? Cov ntsiab lus ntsig txog yuav muab qhia hauv qab no. Feem ntau cov khoom siv hluav taws xob hloov hluav taws xob zoo thiab cov resistors yog qhov zoo sib xws thiab haum.
I. Discharge kuj
Qhov tso tawm resistor R1 yuav tsum raug xaiv me me li sai tau thiaj li tawm qhov chaw txaus rau kev xaiv lub peev xwm ntawm X capacitor. Kev xaiv ntawm R1 kuj tseem yuav tsum xav txog qhov kev tiv thaiv hluav taws xob (feem ntau cov hlau oxide zaj duab xis resistors raug xaiv, nrog rau qhov txo qis ntawm 0.75) thiab kev siv hluav taws xob (txo qis ntawm 0.6 lub zog ntsuas). Piv txwv tias qhov ntsuas lub zog ntawm cov resistor xaiv yog PR thiab qhov siab tshaj plaws ntawm cov khoom siv hluav taws xob yog VINmax, ces R1" (Vinmax) 2 / (0.6 × PR)
1. Piv txwv li, PR=2W, vinmax=300V, R1> 75 K, R1=100 K. Lwm qhov kev txwv ntawm R1 yog qhov kev siv hluav taws xob tam sim tsis tuaj yeem tshaj plaub npaug ntawm lub zog ntsuas. Qhov siab tshaj plaws tam sim no lub zog noj ntawm R1 yog cuam tshuam nrog qhov seem voltage tom qab surge los yog xob laim tawm tsam los ntawm kev tiv thaiv Circuit Court. Thaum qhov hluav taws xob seem yog 1200V, R1 yuav tsum tau ua raws li cov cai hauv qab no: R1 12002 / (4 × Pr)
2.Los hloov Pr=2W rau hauv qhov sib npaug saum toj no, R1> 180K tau txais. Yog li ntawd, R1=100k tsis txaus siab rau qhov xwm txheej no. Yog li, R1=200K yog qhov tsim nyog. Nws yuav tsum tau muab sau tseg ntawm no hais tias txoj hauj lwm ntawm R1 tseem yog ib qho tseem ceeb xav txog lub instantaneous hwj chim noj ntawm tus tawm resistor R1. Muab R1 nyob rau hauv pem hauv ntej yog pom tseeb tsis tsim nyog, tab sis nws' qhov zoo tshaj plaws yog muab tso rau hauv nruab nrab lossis rov qab.
Txhawm rau txo qis R1 ntxiv, siv ob lossis ntau qhov sib npaug sib npaug tuaj yeem siv, nyob ntawm qhov xwm txheej. Thaum ob lub resistors ntawm 50A roj teeb nyob rau hauv parallel, qhov paug tawm yog R1=100K.
II.X thiab Y capacitor
1. X capacitance
1) Kev xaiv ntawm X capacitor
Kev xaiv ntawm X capacitor yog txwv los ntawm lub sijhawm tso tawm. Raws li qhov yuav tsum tau ua los ntawm kev ruaj ntseg cov cai, lub sij hawm los ntawm kev tso tawm ntawm cov input voltage mus rau qhov siab tshaj plaws kev nyab xeeb voltage ntawm 42.4 V yog tsawg tshaj li 1s, uas yuav tsum tau kwv yees los ntawm cov nram qab no empirical mis: CX yog tag nrho cov X capacitors. Cx" 1 / (2.2 × R1)
2) R1=100K yog hloov mus rau qhov sib npaug saum toj no kom tau txais: Cx< 4.5uf,="" coj="" cx="4.4uF," muaj="" ob="" lub="" capacitor="" nyob="" rau="" hauv="" tag="" nrho,="" thiab="" lub="" peev="" xwm="" ntawm="" txhua="" x="" capacitor="" yog="">
3) Cov yam ntxwv zaus ntawm Hom X capacitors (tsis tshua muaj ESR thiab ESL)
Rau cov capacitors ntawm tib cov khoom, lub peev xwm me dua, qhov zoo dua cov yam ntxwv zaus. Tus yam ntxwv zaus ntawm lub capacitor yog tias tag nrho qhov sib npaug capacitance reactance txo qis raws li qhov zaus nce, tab sis lub capacitance reactance nce ntawm qee zaus. Yog hais tias qhov zaus no txhais tau tias yog qhov zaus tig ntawm lub capacitance reactance, qhov me dua qhov capacitance, qhov ntau dua qhov zaus. Yog li ntawd, txhawm rau kom tau txais tib lub peev xwm, ntau lub peev xwm me me tuaj yeem txuas nrog rau tib lub sijhawm, uas tuaj yeem txhim kho cov yam ntxwv ntawm lub tshuab hluav taws xob ntau zaus.
4) Voltage kuj yuav tsum tau rau X capacitors
Kev xaiv ntawm X capacitors yuav tsum tau xav txog qhov voltage kuj (derated raws li 0.6 ntawm qhov ntsuas voltage): txij li thaum X capacitor nyob ze ntawm cov tswv yim ntawm cov kab hluav taws xob, nws yuav tsum muaj peev xwm tiv taus qhov hluav taws xob hloov pauv siab (txog 1200V).
Hauv cov ntsiab lus, 2.2uF capacitor tuaj yeem xaiv rau txhua X capacitor hauv Circuit Court. Nws ntsuas voltage yog 275VAC thiab instantaneous voltage yog 1500VAC / 1s thiab 2500VAC / 0.1s.
2. Y capacitor
1) Kev xaiv ntawm Y capacitor
Qhov kev xaiv ntawm Y capacitor muaj peev xwm raug txwv los ntawm cov xau tam sim no. Raws li cov cai tswj kev nyab xeeb, cov xau tam sim no los ntawm theem kab lossis kab nruab nrab mus rau hauv av yuav tsum tsis pub tshaj 3.5 mA ntawm qhov ntsuas hluav taws xob. Piv txwv tias qhov capacitance ntawm theem kab lossis kab nruab nrab rau hauv av yog Cy, ces 220 × 2πfo × Cy<>
2) Fo = 50Hz yog lub zog zaus. Hloov cov qauv saum toj no, peb tau CY = (cy1 + Cy3) = (Cy2 + CY4)< 0,056f="" ua.="" xav="" tias="" cov="" khoom="" siv="" nws="" tus="" kheej="" muaj="" qee="" yam="" xau="" tam="" sim="" no,="" cy="0.02uF." yog="" li="" txhua="" tus="" y="" capacitor="" yog="">
3) Rau qhov yuav tsum tau muaj tus yam ntxwv zaus rau Y capacitors, saib kev xaiv ntawm X capacitor.
Thaum xaiv X thiab Y capacitors, nws yog ib qho tseem ceeb kom tau txais cov capacitance me me los ntawm kev sib txuas sib txuas, uas yuav txhim kho cov yam ntxwv siab zaus ntawm cov capacitors. Lwm qhov tseem ceeb ntawm cov yam ntxwv zaus ntawm cov capacitors yog tias thaum lub zaus qis dua qhov zaus ntawm lub kauj, kev sib raug zoo ntawm cov capacitance reactance thiab zaus yog: ZC=1 / (2? FC), uas yog, qhov loj dua lub peev xwm ntawm ib leeg. capacitor, qhov tsawg dua qhov capacitance. Reactance Txawm li cas los xij, thaum lub zaus ntau tshaj qhov kev sib hloov zaus ntawm qhov sib txawv ntawm cov capacitors, tag nrho cov capacitance reactance yuav zoo ib yam li cov zaus nce. Hauv lwm lo lus, rau UHF (frequencies ntau dua 50MHz), capacitors ntawm qhov sib txawv (rau microcontrollers) muaj cov nyhuv tib yam, xws li 0.1uf sib npaug 0.001uf.
Hauv cov ntsiab lus, ob 4700pF lossis peb 3300pF capacitors tuaj yeem siv ua ke rau y capacitors hauv Circuit Court. Rated voltage 275VAC, instantaneous voltage 2500VAC / 1s, 5000Vac / 0.1s. Kab lus no tsuas yog muab rau koj nkag siab ua ntej ntawm kev hloov hluav taws xob. Qhov no yuav pab koj pib. Nyob rau tib lub sijhawm, nws yuav tsum tau sau cov ntsiab lus tas liized kom koj tuaj yeem txhim kho koj tus kheej kev txawj ntse.
