Dielectric - dab tsi yog nws? Cov khoom ntawm dielectrics

Lub dielectric yog ib yam khoom los yog cov khoom uas ua suab tsis siv hluav taws xob tam sim no. Xws li kev sib txuas lus tau los ntawm vim muaj tsawg tus electrons thiab ions. Cov khoom no yog tsim hauv cov khoom siv uas tsis yog siv hluav taws xob thaum tsuas kub kub. Hais txog dab tsi yog ib qho dielectric thiab yuav tsum tau sib tham nyob rau hauv no tsab xov xwm.

Kev piav qhia

Txhua tus tshuab hluav taws xob lossis hluav taws xob ua hluav taws xob, hluav taws xob hluav taws xob los yog nqi hluav taws xob tawm ntawm nws tus kheej los ntawm nws tus kheej tam sim no, tiam sis lub cuab yeej siv yog tias qhov tam sim no me me ntawm qhov siab yuav khiav hauv nws txawm tias muaj kev kub siab tshaj 550 V. Qhov hluav taws xob tam sim no hauv lub dielectric yog cov lus taw kev ntawm cov nqi uas tau hais hauv ib qho kev coj ua (ua tau zoo thiab tsis pom zoo).

Hom currents

Qhov hluav taws xob hluav taws xob ntawm dielectrics yog ua raws li:

• Kev nqhis dej yog qhov tam sim no uas muaj nyob hauv lub dielectric ntawm ib qho tam sim no mus txog thaum nws ncav cuag ib qho chaw nruab nrab, hloov cov kev taw qhia thaum qhov hluav taws xob raug qhib thiab siv rau nws thiab thaum nws raug kaw. Nrog alternating tam sim no, lub zog nyob rau hauv lub dielectric yuav tam sim no nyob rau hauv nws tag nrho cov sij hawm thaum nws yog nyob rau hauv qhov kev txiav txim ntawm lub teb hluav taws xob.
• Kev hluav taws xob hluav taws xob - kev txav ntawm cov electrons nyob rau hauv qhov kev txiav txim ntawm ib cheeb tsam.
• Ionic conductivity yog txoj lus taw kev ntawm ions. Nws pom muaj nyob rau hauv cov ntsiab lus ntawm electrolytes - cov ntsev, cov acids, alkali, thiab lwm yam nyob rau hauv ntau lub dielectrics.
• Txoj kev siv hluav taws xob los ntawm kev siv hluav taws xob (Molyon electric conductivity) yog qhov kev txiav txim ntawm cov nqi uas hu ua cov molyons. Nws pom muaj nyob rau hauv kev kaw lus, kev rho tawm thiab kev ncua. Lub phenomenon ntawm tsab ntawv tsa suab ntawm molyons nyob rau hauv ib qho hluav taws xob yog hu ua electrophoresis.

Insulating ntaub ntawv cov dej num los ntawm lub xeev ntawm aggregation thiab tshuaj xwm. Cov qub raug faib ua cov khoom, kua, gaseous thiab solidifying. Los ntawm cov tshuaj muaj peev xwm raug muab faib ua cov organic, cov ntaub ntawv cog lus thiab cov ntaub ntawv organoelemental.

Hluav taws xob ua kom muaj zog ntawm dielectrics raws li xeev xwm txheej:

• Hluav taws xob ua kom muaj roj. Gaseous cov khoom muaj ib qho kev tsis tshua muaj neeg muaj peev xwm tsawg. Nws tuaj yeem tshwm sim thaum tsis muaj cov khoom pub dawb, uas tshwm ntawm lub zog ntawm sab nrauv thiab sab hauv, hluav taws xob thiab cov yam ntxwv: hluav taws xob xoo hluav taws xob thiab hom kab mob, cov sib tsoo ntawm molecules thiab cov khoom ua txhaum, thermal yam.
• Hluav taws xob ua hluav taws xob ntawm lub cev dielectric. Txaus siab rau: tus qauv ntawm molecule, kub, impurities, muaj cov nqi loj ntawm electrons thiab ions. Qhov hluav taws xob ua kom muaj hluav taws xob nyob ntawm lub cev dielectrics yog nyob ntawm seb muaj dej ntau npaum li cas thiab cov khoom tsis haum. Lub conductivity ntawm qhov hluav taws xob ntawm cov paib ncov qaumteb yog tsim los ntawm cov kua uas muaj cov kua xoos tawm. Thaum muab piv rau cov roj ntsha thiab cov kua qaub tsis paug, kev pom zoo kom zoo dua hauv kev ua haujlwm yog thawj. Yog tias cov kua ntxuav cov impurities, qhov no yuav pab txo nws cov khoom siv hluav taws xob. Raws li cov conductivity ntawm cov kua tshuaj thiab nws cov kub nce, ib tug thawj hauv nws viscosity tshwm sim, ua rau kom qhov nce ntawm lub mobility ntawm ions.
• Khoom dielectrics. Lawv cov hluav taws xob ua hluav taws xob yog tshwm sim los ntawm kev txav ntawm cov khoom siv ntawm lub dielectric thiab impurities. Hauv kev khov kho ntawm cov hluav taws xob tam sim no, hluav taws xob conductivity yog qhia.

Lub cev ntawm dielectrics

Nrog lub cev nqaij daim tawv ntawm cov khoom sib npaug zos tsawg dua 10-5 Ohm *, lawv tuaj yeem raug ntaus nqi rau cov neeg sib tw. Yog tias ntau tshaj 108 Ohm * m - mus rau dielectrics. Muaj qee zaum thaum lub cev tiv thaiv yuav muaj ntau zaus ntau dua li tus neeg xyuas pib. Nyob rau hauv lub luv 10-5-108 Ω * m yog ib qho khoom siv rau semiconductor. Cov khoom siv hlau yog ib qho zoo ntawm tus neeg siv hluav taws xob tam sim no.

Ntawm tag nrho Mendeleyev rooj, tsuas yog 25 ntawm cov ntsiab lus xa mus rau non-hlau, thiab 12 ntawm lawv, tejzaum nws, yuav nrog cov khoom ntawm lub semiconductor. Tab sis, tsis tas li ntawd, dhau li ntawm cov khoom hauv lub rooj, muaj ntau ntau cov phom sij, cov dej los yog cov tshuaj chem nrog cov khoom ntawm tus neeg xyuas pib, semiconductor los yog dielectric. Tawm los ntawm qhov no, nws yog qhov nyuaj rau kos ib lub ntsej muag tseeb ntawm qhov tseem ceeb ntawm ntau yam tshuaj nrog lawv cov resistances. Piv txwv li, nrog rau qhov txo qhov kub thiab txias, lub semiconductor yuav coj zoo li lub dielectric.

Daim ntawv thov

Kev siv cov ntaub ntawv tsis yog cov khoom siv yog cov uas muaj ntau heev, vim tias nws yog ib qho ntawm cov qauv nrov tshaj plaws ntawm cov khoom hluav taws xob. Nws tau paub meej heev tias lawv tuaj yeem siv ua tsaug rau cov khoom nyob rau hauv daim ntawv ua ub no thiab cov ntawv tsis muaj tseeb.

Nyob rau hauv daim ntawv passive, cov khoom ntawm dielectrics yog siv rau hauv cov khoom siv insulating.

Nyob rau hauv kev ua ub no lawv siv nyob rau hauv ferroelectrics, raws li tau zoo raws li nyob rau hauv cov ntaub ntawv rau radiators ntawm laser technology.

Qhov pib dielectrics

Cov ntau hom xws li:

• Iav.
• Roj Hmab.
• Roj.
• Asphalt.
• Porcelain.
• Quartz.
• Cov huab cua.
• Lub pob zeb diamond.
• Ntshiab dej.
• Yas.

Dab tsi yog dielectric kua?

Polarization ntawm no hom tshwm sim nyob rau hauv lub tshav pob ntawm hluav taws xob tam sim no. Cov neeg tawm cov kua tau siv nyob rau hauv cov txheej txheem rau cov khoom ntim los yog cov khoom siv rau cov khoom siv. Muaj 3 hom kawm dielectrics kua:

Cov roj roj yog cov tsis muaj zog thiab feem ntau tsis-ncov qaumteb qabteb. Feem ntau lawv siv cov khoom siv hluav taws xob: cov tshuab hluav taws xob, cov dej muaj hluav taws xob. Transformer roj - ib tug uas tsis yog-polar dielectric. Cable roj tau pom daim ntawv thov nyob rau hauv lub impregnation ntawm insulating thiab cov ntawv xov hlau nrog voltage txog li 40 kV, raws li tau zoo raws li coatings raws li hlau nrog ib tug tam sim no ntawm ntau tshaj 120 kV. Cov roj transformer muaj ib txoj dej huv dua li cov roj condenser. Qhov hom ntawm dielectric tau ua nyob rau hauv ntau lawm, txawm tias tus nqi siab ntawm kev tsim khoom ntau nrog cov analog tshuaj thiab cov khoom.

Dab tsi yog qhov hluav taws xob dielectric? Niaj hnub no, nws yog txwv tsis pub txhua qhov chaw vim muaj kev toxicity, vim nws yog ua los ntawm cov roj chlorinated. Lub cev dielectric, raws li cov yeeb-tshuaj uas muaj roj, muaj kev nyab xeeb thiab muaj kev noj nyob zoo. Cov tsiaj no tsis ua rau xeb hlau thiab muaj cov khoom uas tsis muaj hygroscopicity. Muaj ib lub dielectric dilute uas muaj ib lub koom haum organofluorine, uas yog tshwj xeeb tshaj yog nrov vim tias nws cov kev tsis sib haum xeeb, cov khoom txig thiab oxidative stability.

Thiab lub xeem hom yog zaub roj. Lawv yog cov mob qia dub, nrog rau linen, castor, tung, thiab hemp. Cov roj hmab hluav taws xob yog rhuab heev thiab siv nyob rau hauv ntawv condensers. Cov seem uas yog cov roj yog cov evaporable. Evaporation nyob rau hauv lawv yog vim tsis yog ntuj evaporation, tab sis los ntawm ib cov tshuaj tiv thaiv hu ua polymerization. Nws nquag siv cov tshuaj txham thiab xim.

Xaus

Tsab ntawv xov xwm tau muab coj los nthuav qhia meej txog dab tsi yog ib qho dielectric. Ntau hom thiab lawv cov khoom raug hais. Ntawm chav kawm, kom nkag siab txog tag nrho cov subtlety ntawm lawv cov yam ntxwv, peb yuav tau kawm nyob rau hauv ntau dua qhov tob ntawm physics seem txog lawv.