Kev txiav txim siab qhov kev ua tau zoo ntawm lub thermistor thiab xaiv cov khoom tsim nyog yuav tsum tau ua tib zoo saib xyuas ntawm ob qho tib si technical parameters thiab daim ntawv thov scenarios. Nov yog phau ntawv qhia ntxaws:
I. Yuav ua li cas txiav txim qhov zoo ntawm ib tug Thermistor?
Cov yam ntxwv tseem ceeb ntawm kev ua haujlwm yog qhov tseem ceeb rau kev ntsuam xyuas:
1. Nominal Resistance Value (R25):
- Txhais:Tus nqi tiv thaiv ntawm qhov ntsuas kub tshwj xeeb (feem ntau yog 25 ° C).
- Kev Txiav Txim Siab:Tus nqi nominal nws tus kheej tsis yog qhov zoo los yog phem; tus yuam sij yog seb nws ua tau raws li qhov tsim nyog ntawm daim ntawv thov Circuit Court (xws li, voltage divider, tam sim no limiting). Consistency (kev sib kis ntawm qhov tseem ceeb nyob rau hauv tib batch) yog ib qho kev qhia tseem ceeb ntawm kev tsim khoom zoo - me me dispersion zoo dua.
- Nco tseg:NTC thiab PTC muaj qhov sib txawv ntawm qhov sib txawv ntawm 25 ° C (NTC: ohms rau megohms, PTC: feem ntau ohms mus rau pua pua ohms).
2. B Tus Nqi (Beta Tus Nqi):
- Txhais:Ib qho parameter piav txog qhov rhiab heev ntawm lub thermistor qhov kev hloov pauv nrog qhov kub thiab txias. Feem ntau yog hais txog tus nqi B ntawm ob qhov kub thiab txias (piv txwv li, B25/50, B25/85).
- Kev suav cov qauv: B = (T1 * T2) / (T2 - T1) * ln(R1 / R2)
- Kev Txiav Txim Siab:
- NTC:Tus nqi B siab dua qhia tau tias muaj qhov kub thiab txias ntau dua thiab qhov kev hloov siab hloov nrog qhov kub thiab txias. High B qhov tseem ceeb muab kev daws teeb meem siab dua hauv kev ntsuas qhov kub thiab txias tab sis tsis zoo linearity dhau qhov kub ntawm qhov dav. Consistency (B tus nqi dispersion hauv ib pawg) yog qhov tseem ceeb.
- PTC:Tus nqi B (txawm tias qhov kub thiab txias coefficient α ntau dua) piav qhia txog tus nqi ntawm kev tiv thaiv nce hauv qab Curie point. Rau kev hloov daim ntawv thov, qhov siab ntawm qhov kev tawm tsam dhia ze ntawm Curie point (α tus nqi) yog qhov tseem ceeb.
- Nco tseg:Cov tuam txhab sib txawv tuaj yeem txhais cov txiaj ntsig B siv qhov sib txawv ntawm qhov sib txawv (T1 / T2); xyuas kom sib xws thaum sib piv.
3. Qhov tseeb (Kev kam rau siab):
- Txhais:Qhov tso cai sib txawv ntawm tus nqi tiag tiag thiab tus nqi nominal. Feem ntau categorized li:
- Resistance Tus nqi raug:Tso cai sib txawv ntawm qhov tseeb tsis kam ntawm nominal tsis kam ntawm 25 ° C (piv txwv li, ± 1%, ± 3%, ± 5%).
- B Tus nqi raug:Tso cai sib txawv ntawm tus nqi B tiag tiag los ntawm tus nqi nominal B (piv txwv li, ± 0.5%, ± 1%, ± 2%).
- Kev Txiav Txim Siab:Cov neeg raug siab dua qhia tau tias kev ua tau zoo dua, feem ntau yog tus nqi siab dua. Cov ntawv thov kev ua haujlwm siab (piv txwv li, ntsuas qhov kub thiab txias, kev them nyiaj circuits) yuav tsum muaj cov khoom muaj tseeb (piv txwv li, ± 1% R25, ± 0.5% B tus nqi). Cov khoom siv qis dua tuaj yeem siv rau hauv cov ntawv thov tsawg dua (piv txwv li, kev tiv thaiv overcurrent, qhov ntsuas kub ntxhib).
4. Temperature Coefficient (α):
- Txhais:Tus txheeb ze ntawm kev hloov pauv nrog qhov kub thiab txias (feem ntau nyob ze ntawm qhov ntsuas kub ntawm 25 ° C). Rau NTC, α = - (B / T²) (%/°C); rau PTC, muaj qhov zoo me me α hauv qab Curie point, uas nce ntau nyob ze nws.
- Kev Txiav Txim Siab:A siab |α| tus nqi (tsis zoo rau NTC, qhov zoo rau PTC ze ntawm qhov hloov pauv) yog qhov zoo dua hauv cov ntawv thov uas xav tau cov lus teb ceev lossis siab rhiab heev. Txawm li cas los xij, qhov no kuj txhais tau hais tias qhov kev ua haujlwm nqaim dua thiab ua haujlwm tsis zoo.
5. Thermal Time Constant (τ):
- Txhais:Nyob rau hauv xoom-power tej yam kev mob, lub sij hawm yuav tsum tau rau lub thermistor kub hloov los ntawm 63.2% ntawm tag nrho cov sib txawv thaum lub ambient kub undergoes ib kauj ruam hloov.
- Kev Txiav Txim Siab:Lub sij hawm me me tsis tu ncua txhais tau hais tias cov lus teb sai dua rau qhov ntsuas kub hloov pauv. Qhov no yog qhov tseem ceeb heev rau cov ntawv thov uas xav tau kev ntsuas kub ceev lossis cov tshuaj tiv thaiv (xws li, kev tiv thaiv overtemperature, airflow detection). Lub sij hawm tas li yog cuam tshuam los ntawm pob loj, cov khoom siv hluav taws xob muaj peev xwm, thiab thermal conductivity. Me me, unencapsulated hlaws NTCs teb sai tshaj plaws.
6. Dissipation Constant (δ):
- Txhais:Lub zog yuav tsum tau nce lub thermistor qhov kub ntawm 1 ° C saum toj no qhov kub thiab txias vim nws lub zog dissipation (unit: mW / ° C).
- Kev Txiav Txim Siab:Qhov ntau dua dissipation tas li txhais tau hais tias tsis tshua muaj cua sov ntawm tus kheej (piv txwv li, qhov kub thiab txias me dua rau tib qhov tam sim no). Qhov no tseem ceeb heev rau kev ntsuas qhov ntsuas kub kom raug, vim tias qhov ntsuas kub ntawm tus kheej qis txhais tau tias qhov ntsuas me me yuam kev. Thermistors uas tsis tshua muaj dissipation tsis tu ncua (me me, thermally insulated pob) yog feem ntau ua rau nws tus kheej ua cua sov tsis zoo los ntawm kev ntsuas tam sim no.
7. Kev ntsuas siab tshaj plaws (Pmax):
- Txhais:Lub zog siab tshaj plaws uas lub thermistor tuaj yeem ua haujlwm ruaj khov rau lub sijhawm ntev ntawm qhov ntsuas kub ntawm qhov ntsuas kub tsis muaj kev puas tsuaj lossis qhov ntsuas qhov ntsuas mus tas li.
- Kev Txiav Txim Siab:Yuav tsum ua kom tau raws li qhov xav tau ntawm lub zog siab tshaj plaws ntawm daim ntawv thov nrog cov npoo txaus (feem ntau derated). Resistors uas muaj peev xwm tuav tau ntau dua yog txhim khu kev qha.
8. Kev khiav hauj lwm qhov kub thiab txias:
- Txhais:Lub ambient kub lub sij hawm nyob rau hauv uas lub thermistor muaj peev xwm ua hauj lwm ib txwm thaum tsis nyob rau hauv cov kev txwv qhov tseeb.
- Kev Txiav Txim Siab:Qhov dav dav txhais tau tias siv tau ntau dua. Xyuas kom meej qhov siab tshaj plaws thiab qis tshaj qhov ntsuas kub nyob hauv daim ntawv thov poob hauv qhov ntau.
9. Kev ruaj ntseg thiab kev ntseeg tau:
- Txhais:Lub peev xwm los tuav ruaj khov thiab B qhov tseem ceeb thaum siv mus ntev lossis tom qab muaj kev kub ntxhov thiab kev cia siab / qis.
- Kev Txiav Txim Siab:High stability yog qhov tseem ceeb rau kev siv precision. Iav-encapsulated lossis tshwj xeeb kho NTCs feem ntau muaj kev ruaj ntseg ntev dua li epoxy-encapsulated sawv daws yuav. Kev hloov pauv kev ua siab ntev (tus naj npawb ntawm cov voj voog hloov nws tuaj yeem tiv taus yam tsis ua haujlwm) yog qhov tseem ceeb ntawm kev ntseeg siab rau PTCs.
II. Yuav Ua Li Cas Xaiv Qhov Zoo Thermistor rau Koj Cov Kev Xav Tau?
Cov txheej txheem xaiv suav nrog kev ua haujlwm tsis sib xws rau cov kev xav tau ntawm daim ntawv thov:
1. Txheeb xyuas hom kev thov:Qhov no yog lub hauv paus.
- Kev ntsuas kub: NTCyog nyiam. Tsom ntsoov rau qhov raug (R thiab B tus nqi), kev ruaj ntseg, kev khiav hauj lwm kub ntau, cov nyhuv cua sov ntawm tus kheej (dissipation tas li), teb ceev (lub sij hawm tas li), linearity (los yog seb yuav tsum tau them nyiaj linearization), thiab pob hom (kev sojntsuam, SMD, iav-encapsulated).
- Kev them nyiaj kub kub: NTCfeem ntau siv (paub rau drift hauv transistors, muaju, thiab lwm yam). Xyuas kom NTC cov yam ntxwv kub zoo sib xws rau cov yam ntxwv drift ntawm cov khoom siv nyiaj tau los, thiab ua kom muaj kev ruaj ntseg thiab qhov tseeb.
- Inrush Tam sim no txwv: NTCyog nyiam. Cov tsis tseem ceeb yog covNominal Resistance Tus Nqi (txiav txim siab thawj zaug txwv cov nyhuv), Qhov siab tshaj plaws Steady-State Current/Power(Txiav txim siab tuav lub peev xwm thaum ua haujlwm ib txwm muaj),Maximum Surge Current Withstand(I²t tus nqi lossis qhov siab tshaj tam sim no rau cov qauv tshwj xeeb), thiabLub Sijhawm Rov Qab(lub sij hawm kom txias mus rau lub xeev uas tsis muaj zog tom qab fais fab tuag, cuam tshuam rau kev hloov pauv ntau zaus).
- Overtemperature / Overcurrent Protection: PTC(resettable fuses) feem ntau yog siv.
- Kev tiv thaiv overtemperature:Xaiv lub PTC nrog Curie taw tes me ntsis saum toj kawg nkaus ntawm kev ua haujlwm kub. Tsom ntsoov rau qhov ntsuas kub mus txawv tebchaws, lub sijhawm mus txawv tebchaws, rov pib dua qhov ntsuas kub, ntsuas qhov ntsuas hluav taws xob / tam sim no.
- Kev tiv thaiv overcurrent:Xaiv ib lub PTC nrog ib tug tuav tam sim no me ntsis saum lub Circuit Court qhov ib txwm ua hauj lwm tam sim no thiab ib tug mus txawv tebchaws tam sim no nyob rau hauv qis dua theem uas yuav ua rau puas. Qhov tseem ceeb tsis muaj xws li tuav tam sim no, mus txawv tebchaws tam sim no, max voltage, max tam sim no, mus txawv tebchaws lub sij hawm, kuj.
- Ua kua Level/Flow Detection: NTCfeem ntau yog siv, siv nws tus kheej ua kom sov. Cov tsis tseem ceeb yog dissipation tas li, thermal lub sij hawm tas li (teb lus ceev), lub zog tuav, thiab pob (yuav tsum tiv thaiv kev tawm tsam).
2. Txiav txim qhov tseem ceeb Parameter Requirements:Quantify xav tau raws li qhov kev thov scenario.
- Kev ntsuas ntau:Qhov ntsuas kub tsawg kawg thiab siab tshaj plaws yuav tsum ntsuas.
- Kev ntsuas qhov tseeb:Dab tsi kub qhov yuam kev ntau yog txais tau? Qhov no txiav txim siab qhov yuav tsum tau muaj kev tiv thaiv thiab qib B tus nqi raug.
- Teb ceev yuav tsum tau:Yuav kuaj xyuas qhov ntsuas kub npaum li cas? Qhov no txiav txim siab lub sij hawm tas li, cuam tshuam rau kev xaiv pob.
- Circuit Court interface:Lub luag haujlwm ntawm lub thermistor hauv Circuit Court (voltage divider? series tam sim no limiter?). Qhov no txiav txim siab qhov xav tau nominal tsis kam ntau thiab tsav tam sim no / voltage, cuam tshuam rau tus kheej lub tshuab cua sov yuam kev.
- Ib puag ncig tej yam kev mob:Humidity, tshuaj corrosion, mechanical stress, xav tau kev rwb thaiv tsev? Qhov no cuam tshuam ncaj qha rau pob xaiv (xws li, epoxy, iav, stainless hlau sheath, silicone-coated, SMD).
- Kev txwv kev siv fais fab:Lub tshuab hluav taws xob tuaj yeem muab tau ntau npaum li cas? Kev tso cai rau tus kheej qhov kub ntawm qhov kub nce? Qhov no txiav txim siab qhov lees txais dissipation tas li thiab tsav theem tam sim no.
- Reliability Requirements:Xav tau kev ruaj ntseg ntev ntev? Yuav tsum tau txais kev hloov pauv ntau zaus? Xav tau high voltage / tam sim no muaj peev xwm?
- Size Constraints:PCB qhov chaw? Mounting qhov chaw?
3. Xaiv NTC lossis PTC:Raws li Kauj Ruam 1 (kev thov hom), qhov no feem ntau txiav txim siab.
4. Lim cov qauv tshwj xeeb:
- Sib tham Manufacturer Datasheets:Qhov no yog txoj kev ncaj thiab muaj txiaj ntsig tshaj plaws. Cov tuam txhab loj xws li Vishay, TDK (EPCOS), Murata, Semitec, Littelfuse, TR Ceramic, thiab lwm yam.
- Match Parameters:Raws li cov kev cai tseem ceeb uas tau teev tseg hauv Kauj Ruam 2, tshawb nrhiav cov ntaub ntawv rau cov qauv kev sib ntsib rau cov qauv nominal tsis kam, B tus nqi, qib raug, kev khiav hauj lwm kub ntau, pob loj, dissipation tas li, lub sij hawm tas li, max zog, thiab lwm yam.
- Hom pob:
- Surface Mount Device (SMD):Me me, haum rau high-density SMT, tus nqi qis. Nruab nrab teb ceev, nruab nrab dissipation tas li, qis zog tuav. Qhov ntau thiab tsawg: 0201, 0402, 0603, 0805, thiab lwm yam.
- Glass-Encapsulated:Cov lus teb ceev heev (lub sij hawm me me tsis tu ncua), zoo stability, siab kub resistant. Me me tab sis yooj yim. Feem ntau siv los ua cov tub ntxhais hauv precision kub sojntsuam.
- Epoxy-coated:Tus nqi qis, qee qhov kev tiv thaiv. Nruab nrab teb ceev, stability, thiab kub kuj.
- Axial / Radial Leaded:Lub zog tuav ntau dua, yooj yim rau tes soldering lossis dhau-qhov mounting.
- Hlau / yas Encased sojntsuam:Yooj yim rau mount thiab ruaj ntseg, muab rwb thaiv tsev, waterproofing, corrosion kuj, mechanical tiv thaiv. Kev teb qeeb qeeb (nyob ntawm vaj tse / sau). Haum rau kev lag luam, cov khoom siv uas xav tau kev txhim khu kev qha mounting.
- Surface Mount Fais Fab Hom:Tsim los rau siab zog inrush limiting, loj loj, muaj zog tuav.
5. Xav txog tus nqi thiab muaj:Xaiv tus qauv tsim nyog nrog cov khoom siv ruaj khov thiab siv tau cov sij hawm ua tau raws li qhov yuav tsum tau ua. Cov neeg raug siab, pob tshwj xeeb, cov qauv teb ceev yog feem ntau kim dua.
6. Ua Kev Xeem Xeem yog tias tsim nyog:Rau cov ntawv thov tseem ceeb, tshwj xeeb tshaj yog muaj qhov raug, teb ceev, lossis kev ntseeg siab, kuaj cov qauv raws li qhov tseeb lossis simulated kev ua haujlwm.
Cov ntsiab lus ntawm cov kauj ruam xaiv
1. Txhais Kev Xav Tau:Daim ntawv thov yog dab tsi? Ntsuas dab tsi? Tiv thaiv dab tsi? Compensating rau dab tsi?
2. Txiav txim siab hom:NTC (Measure/Compensate/Limit) los yog PTC (Protect)?
3. Quantify Parameters:Qhov kub thiab txias? Qhov tseeb? Teb ceev? Lub hwj chim? Loj? Ib puag ncig?
4. Tshawb xyuas cov ntaub ntawv:Lim cov neeg sib tw ua qauv raws li qhov xav tau, sib piv cov lus ntsuas.
5. Kev tshuaj xyuas pob:Xaiv pob haum raws li ib puag ncig, mounting, teb.
6. Sib piv Tus Nqi:Xaiv tus qauv kev lag luam uas ua tau raws li qhov yuav tsum tau ua.
7. Siv tau:Kuaj cov qauv kev ua tau zoo hauv qhov tseeb lossis simulated rau cov ntawv thov tseem ceeb.
Los ntawm kev txheeb xyuas qhov kev ua tau zoo thiab kev sib txuas nrog cov ntawv thov tshwj xeeb, koj tuaj yeem txiav txim siab thermistor zoo thiab xaiv qhov tsim nyog tshaj plaws rau koj qhov project. Nco ntsoov, tsis muaj "zoo tshaj" thermistor, tsuas yog lub thermistor "tsim" tshaj plaws rau ib daim ntawv thov. Thaum xaiv cov txheej txheem, cov ntaub ntawv ntxaws ntxaws yog koj cov ntaub ntawv siv tau zoo tshaj plaws.
Post lub sij hawm: Jun-15-2025