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ID:4249745
大小:1.26 MB
页数:4页
时间:2017-11-30
《抑制浪涌电流负温度系数ntc热敏电阻器》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、【南京南山半导体有限公司—风华高科热敏电阻器选型资料】www.nscn.com.cnNTCNTCTHERMISTORNTCNTCTHERMISTOROUTLINEThisisaNegativeTemperatureCoefficientResistorWhoseresistancechangeswithambienttemperaturechanges.24Thermistorcomprises2or4kindsofmetaloxidesofiron,nickel,cobalt,manganeseandcopper,beingshapedand12001500Si
2、nteredathightemperature(1200to1500)NTCCriticalTechnicalParametersofNTCThermistorRtRt---ResistanceValueatZero-powerIt'saresistancewhichisgotatafixedtemperatureonabasisofatestingpowerwhichcausesresistancetoVaryinarangewhichcanbeignoredinrelationtothetotaltestingeror.RR25---ResistanceVal
3、ueatRatedZero-power25Thedesignresistanceofthethermistorusuallyreferstothe25resistancevaluegotatZero-powerat25,whichisusuallyindicatedonthethermistor.BBValueBBvaluestandsforthethermalexponentatanegativetemperaturecoefficient.lt'sdefinedasaratioofthebalancebetweenthenaturallogarithmsofr
4、esistancevaluesatzero-powertothebalancebetweenthereciprocalsofthetwotemperatures.Theformulaisasbelow:RT111T1T2RT1B=lnR/()TT=TTlnRRT111T1T2RT1T21221T2B=ln/()=lnRT2T1T2T2T1RT2RTT11Inthisformula:RistheresistanceatZero-powerwhentheT1temperatureisT1RTT22RistheresisrtanceatZero-powerwhenthe
5、temperatureisT2TUnlessotherwisespecified,Bvalueisgotbycalculating2B25(298.theZero-powerresistancesat25(298.15K)and5015K)50(323.15K)(323.15K).It'snotafirmconstantwithintherangeof,Bworkingtemperature.Resistance-to-TemperatureCoefficientatZero-powerTItreferstotheratioofchangesofathermist
6、or.ResistancevalueatZero-powerwhenThetemperature,totheresistancevalueatZero-powerTheformulaisasbelow:1DRTBT=RDT=T1DRTBT2T==RTDTT2TInthisformula,""standsfortheresistance-temperatureTcoefficientatZero-powerwhenthetemperatureisT:R-TRstandsfortheresistancevalueatZero-powerwhentheTTtempera
7、tureisTT(K)Tstandsforthetemperature(inK)BBBstandsforBvalue149【南京南山半导体有限公司—风华高科热敏电阻器选型资料】www.nscn.com.cnMax.steadystatecurrent..maxmax.Themaximumallowablecontinuouscurrentpassingthroughthermistorat25.DissipationCoefficientIt'stheratioofthechangeswithathermistordissipationpower,inapre-s
8、etamb
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