đề cương đo lường

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1. Khi nim v cm bin? Phn loi cm bin? cc vn khi thit k v sdng cm bin

Tr li:Cm bin l mt thit b chu tc ng ca cc i lng vt l cn o m khng c tnh

cht in v cho ta u ra mt i lng mang bn cht in ( nh in tch, in p,

dng in , tr khng ) k hiu l s

c trng in s l hm ca i lng cn o m :S=f(m)

Quan h gia s v m c th l tuyn tnh hay phi tuyn . Song trong thc t d sdng thng thng ngi ta ch to cm bin sao cho c s lin h tuyn tnh gia binthin u ra v bin thin u vo . s=s *m

Trong S gi l nhy ca cm bin Phn bit cm bin :

- phn loi: cm bin tch cc v cm bin th ng.+cm bin tch cc l cc loi cm bin hot ng nh mt my pht in, v mt nguynl n thng da trn cc hiu ng vt l bin i mt dang nng lng no (nhnhit,c,quang) thnh nng lng in.+cm bin th ng l loi cm bin c ch to t cc vt liu c nhng thng s trkhng nhy vi cc i lng o. Gi tr ca tr khng ca cm bin khng nhng phthuc vo hnh dng, kch thc m cn ph thuc vo tnh cht in ca vt liu nh:in tr sut, t thm, hng s in mi-cc vn khi thit k v s dng cm bin:+cc i lng nh hng ti cm binNhit lm thay i cc c trng in, c v kch thc ca cm bin.

m c th lm thay i tnh cht in ca vt liu :p sut, gia tc, dung gy nn bin dng hoc ng sut trongT trng c th gy nn sc in ng cm ng chng chnh ln tn hiu c ch+sai s ca php o: sai s ca h thng v sai s ngu nhin+ nhy ca cm bin+ nhanh-thi gian hi p.

2.Cm bin quang hot ng da trn nguyn l g? Ngun sng ca cm binquang trong thc t l loi g?Tr li:

Cm bin quang hot ng da trn nguyn l:- Trong vt cht cc in t bao quanh ht nhn nh mt lc lin kt vi ht nhn

We , lc ny mnh vi cc in t trong lp trong v yu vi in t lp ngoi ,do cc in t lp ngoi tch khi nguyn t . Khi nh sng chiu ln vtcht nu nng lng ca cc photo ln cp cho in t thng lc lin kt thcc in t trong vt cht s c gii phng tr thnh in t t do.

- in tch c gii phng do chiu sng ph thuc vo bn cht ca vt b chiusng.

Cm bin quang hot ng da trn nguyn l ny.

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Ngun sng ca cm bin quang trong thc t hu ht dng nh sng hng ngoi

3 Ngi ta phn loi cm bin quang da trn nguyn tc no? c im cami loi? Loi no c khong cch pht hin xa nht?

Tr li:

Ngi ta phn loi cm bin quang da trn nguyn tc :Phn loi theo ngun sng gia phn pht v phn thu:- Thu tch bit- Thu pht mt pha s dng gng phn x- Thu pht mt pha s dng phn x khuch tn.

c im ca mi loi:-Thu pht c lp : B pht v thu nm cc thit b c lp nhau to ra nh sng

b thu c cng ln nht , phn bit sng ti cao, pht hin c vt th khngph thuc vo mu sc v b mt vt th, gi thnh cao.- Cm bin phn x gng: khong cch pht hin ln , kh nng phn bit cao , cth phn bit c vt th trong sut , m, bng gi thnh r hn cm bin thu pht

c lp , tin cy cao-Cm bin loi pht x khuch tn : Ch pht hin vt th trong vng gii hn , b nhhng ca mu nn sau vng cm bin , l tng cho nhiu ng dng cn trit tiunn- Loi c khong cch pht hin xa nht l cm bin thu pht c lp

Cu 4:K hiu ca cm bin quang:-Nng lng bc x: Q l nng lng phn x lan truyn hoc bc x di dng

bc x n v l J hoc lm.s- Thng lng nh sng : l cng sut pht x , lan truyn hoc hp th , n v

l W hay lm

- Cng nh sng : I l lung nng lng pht theo 1 hng di mt n vgc khi , n v W/sv hoc Cd.- chi L l t s gia cng nh sng phn x bi mt b mt theo 1 hng

xc nh v din tch h/c ca pt ny trn mp vung gc vi hng , n vW/m2 hoc lm/m2

Cu 5: Trn thn cm bin c ghi :Dark on : khi pht hin vt s cho tn hiu off, khng c vt cho tn hiu onLight on: Khi pht hin vt s cho tn hiu On , khng c vt cho tn hiu Off.Cu 6: Khi mc song song nhiu cm bin quang thu pht tch bit , chng nhiu taphi o v tr phn thu v phn pht .Cu 7: Nguyn l hot ng ca cm bin si quang:

CB si quang l 1 dng ca cm bin quang , nh sng s dng trong cm bin quang lnh sng hng ngoi hoc lazer. nh sng pht ra thit b pht c dn truyn qua 1si quang a n u pht , nh sng p vo vt th phn x li u thu , qua si quangv mch x l .*c im ca cm bin si quang:- Pht hin vt c kch thc nh , thi gian p ng nhanh , pht hin chnh xc ngay ctrong khi iu kin khng CB. Thu pht ln ti 1100mm, phn x khuch i ln ti130mm, phn x xc nh pht hin 6mm.

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Cu 8 : Nguyn l hot ng ca cm bin lazer:Cm bin gm phn t pht lazer , phn t cm nhn v gng. Ngun sng pht ragng 1 phn v chiu vo i tng .Sng phn hi t i tng s giao thoa vi sngpht ra. Nu cc nh sng cng nhau th sng giao thoa c bin gp i bin banu . nu sng phn hi lch pha 1800 th bin sng giao thoa bng 0.

c im:Ngun sng lazer rt n sc , nh hng cao, c kh nng truyn rt xa do thng s dng lm CB phn bit mu , nhn bit hnh dng sn phm.

Cu 9:Cm bin quang c kh nng pht hin kch thc vt th l cm bin lazer.Cm bin c kh nng pht hin vt th gc khut l cm bin thu pht tch bit v cmbin phn x gng .Cm bin c kh nng pht hin vt th c h s hp th nh sng lnCu 10:Trong cc thit b iu khin t xa , phn t nhy sng l : phototranzitorCu 11:

Nu c im ca cng tc hnh trnh? Nu ti l rle xoay chiu th c th s dngcng tc hnh trnh ng/ ngt c khng? Nu cch u ni ti vi tip imthng m?c im ca cng tc hnh trnh :Cng tc hnh trnh dng nhn bit v tr chuyn ng ca c cu my . Cng tc hnhtrnh l mt tip im c kh do tui th khng cao , khng dng c trong mitrng du, m, ha cht .

Cu 12:Nu cu to ca cng tc t? V k hiu ca cng tc t? Trong thc t c cng tct dng tip im thng ng khng? Nu c th cu to ca n nh th no? Cu to ca cng tc t :Cu to ca cng tc t gm c mt tip im li g c dt trong mt bng thytinh rt chn khng v mt nam chm vnh cu > khi tip im li g gn nam chmvnh cu th lc t trng do nam chm sinh ra s ht tip im ng li .K hiu:

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Cu 13:Nu c im ng dng ca cng tc t?

- Cng tc t c tip im t trong bng thy tinh kn nn c th chu c trongmi trng du , m , ha cht . Trong thc t , cng tc t c ng dng nhiu

trong cng nghip nh ch to cm bin mc , nhn bit v tr ca cc chi tit my. c bit trong h thng iu khin kh nn cng tc t c s dng rt phbin nhn bit v tr ca piton chuyn ng trong xilanh.

Cu 14:cm bin tim cn in cm c c im g? Khong cch pht hin cacm bin tim cn in cm ph thuc vo yu t no? Cm bin chu nh

hng ca nhiu no nht? cch khc phc?Tr li:Cm bin tim cn, in cm c c im:u d ca cm bin thng c s dng l mch t h lm bng li st hoc Perit.Trn mch t c cun dy in t . Nu 1 vt kim loi dn in ni kn mch khet h th gi tr in cm ca u d in cm s gim , dng in tiu th tng nucp u d in p xoay chiu.

Khong cch pht hin ca cm bin tim cn in cm ph thuc vo kch thc ,hnh dng vt v dn t ca cv vt th , nhit mi trng

Cm bin tim cn in cm nh hng bi nhiu, khc phc bng cch bc v kimloi cho cm bin v ni t

Cu 15:cm bin tim cn in dung c c im g? Khong cch pht hin ca cmbin tim cn in dung ph thuc vo yu t no? Cm bin chu nh hng canhiu no nht? cch khc phc?

Tr li:Cm bin in cm in dung c c im:Thng l 2 l ng c in tch b mt l 10cm2 dn trn lp Perit cch in hocnha cch in , cm bin tim cn in dung c th xc nh c tt c cc vt c hs in mi khc vi mi trng in mi ngoi khng kh , xc nh c mc tn sthay i Khong cch pht hin hiu qu ca cm bin in dung ph thuc vo m v

sng Cm bin chu nh hng ca nhiu. Cch khc phc :

Cu 16:Mun pht hin vt th hoc cht liu ng trong hp kn th s dng cmbin no? C yu cu g khng?

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Mun pht hin vt th hoc cht liu ng trong hp kn th s dng cm bin tim cnin dung.Yu cu vt th hoc cht liu cha trong thng l cc phi kim loi .Cu 17: Mun nhn bit vt th kim loi n gn c th s dng loi cm bin no?Khong cch ti a t cm bin n vt th l bao nhiu?

Tr li :Mun nhn bit kim loi n gn c th s dng loi cm bin tim cn in cm .Khong cch ti a c th ln n 1m.Cu 18: C th s dng cm bin tim cn in dung lm cm bin o mc c khng?Yu cu c th o c nh th no?Tr li:C th s dng cm bin tim cn in dung lm cm bin o mcYu cu o c:i vi cht lng cch in : t 2 in cc kim loi thng ng trong bnh cha dungdch trong bnh chnh l in mi.

i vi cht lng dn in : s dng cm bin in dung gn ln thnh bnh.o lin tc : Dng 2 que o,1 que o c bc cch in bng lp in mi , mt que okhng bc cch in.Cu 19: c th o c lu lng cht lng bng lu lng k in t, yu cu v chtlng y nh th no?Tr li: o c lu lng cht lng bng lu lng k in t , yu cu v cht lng c dn in khng nh hn 10-5 10-6 siemen/m.Cu 20:Cch u ni ti ca cm bin tim cn in cm c u ra kiu PNP.

Cu 21:Cch u ni vi ti ca cm bin tim cn in cm c u ra kiu PNP?

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Cu 22: Cm bin tim cn in dung l loi cm bin tch cc v n c s bin i nnglng . Khi c 1 vt kim loi n gn nng lng ca b dao ng b tiu hao to nncc dng xoay c cm ng bn trong vt th .

Cu 23: Cm bin tim cn in cm l cm bin tch cc hay th ng? ti sao?

Cu 24:

Cu 25: Cm bin siu m hot ng da trn nguyn tc no? Nu c im cacm bin siu m?Tr li:Nguyn tc hot ng:Khi c lnh yu cu o b iu khin s pht lnh pht ra chu k sng m bc x ra bnngoi khi gp vt chn s phn x tr li b thu. Da vo vn tc t sng v qung thigian t khi pht sng siu m ti khi nhn li suy ra khong cch t vt ti v tr tcm bin c im ca cm bin siu m.

- Khong cch bt vt ln t 2mm-10m thm ch 100m- Dng sng siu m vi tn s ngoi ngng nghe ca tai ngi bt vt- L cm bin thng minh.

Cu 26:Cm bin mc kiu phao c kh thng c ng dng u? N dng ongng hay o lin tc?Tr li:Cm bin phao c kh thng c ng dng trong h thng bm nc tng ca nh cao tng.

- N c s dng o

Cu 27:Yu cu cht lng ca cm bin mc kiu in dn l g?

- Ch ng dng o cc cht lng dn in khng c tnh n mn v khng lncc vt th cch in nh du nhn .

Cu 28 :

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o 3 ngng trong bnh v bng nha dng cm bin in dn cn 4 in cc v cncc gc t y bnh , 3 cc cn li P1, P2, P3 c gn cc v tr m ta cn xc nhmcCu 29 : TNG T 28Cu 30:

Ngun nui cho cc in cc ca cm bin mc kiu in dn c c im g? Tisao?- ngun xoay chiu 10v v: chng hin tng phn ly

Cu 31:Khi o mc cht lng cch in 1 cch lin tc bng phng php thay i indung, ngi ta xc nh mc thng qua hnh thc no?Tr li:

- Khi o mc cht lng cch in 1 cch lin tc bng phng php thay i indung , ngi ta xc nh mc bng cch t 2 in cc ca kim loi ca cm binthng ng trong bnh cha dung dch , nh vy khi dung dch trong bnh bay hihay kt ta s l cho in tch bn cc thay i theo. Sau dng 1 mch in t

xc nh s thay i ca in dung suy ra mc cht lng trung bnh .Cu 32: Khi o mc cht lng dn in 1 cch lin tc bng phng php thay i indung, ngi ta xc nh mc thng qua hnh thc no?

Tr li:Khi o mc cht lng dn in 1 cch lin tc bng phng php thay i in dung

ngi ta xc nh mc bng cch : Dng 2 que o , 1 que o c bc lp inmi , 1 que khng bc cch in . Khi mc cht lng thay i s lm thay idin tch mt ngoi ca que o => lm thay i in dung nn ngta xc nh cmc cht lng trong bnh .

Cu 33:Mun o cht lng c hot tnh ha hc mnh , ngi ta thng dng cc loi cm binbc x nh cm bin tia gama, cm bin sng siu m, cm bin mc x quang hc .Cu 34:Cm bin mc kiu phao bin tr c ng dng u? Cm bin cho ura lin tc hay ngng?Tr li:

- Cm bin mc kiu phao bin tr c ng dng ch th mc xng , du trongcc bnh cha nhin liu ca t , xe my .

- Cm bin cho u ra 1 cch lin tcCu 35: Cm bin mc kiu in dung l tch cc hay th ng? Ti sao?

Cu 36:C 4 phng php o nhit :

- Dng nhit in tr KL- Dng IC cm bin nhit - Dng nhit in tr NTC, PTC- Dng cp nhit

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Cu 38:Mun o nhit ca vt rn cn lm nh th no?-T b mt ca vt ngi ta khoan mt l nh ng knh R v su L. L ny acm bin vo su trong vt rn. tng chnh xc m bo 2 dk sau: L>=10R, khongtrng gia v cm bin v thnh l khoan phi c lp y vt liu dn in ttCu 37:

Mun tng nhit chnh xc ca php o cn gim hiu s nhit gia nhit mitrng o v nhit ca cm bin ..C 2 phng php :-Tng trao i nhit gia cm bin v mi trng o.-Gim trao i nhit gia cm bin v mi trng ngoiCu 39:Nhit in tr l g?-l mt loi cm bin nhit lm vic da trn s thay i ca in tr ca mt s loikim loi khi thay i nhit Cu 40:Thng s Pt-100, Pt -500, Pt 1000 c ngha nh th no?

Tr li:Pt-100 : 00C th in tr Ro ca Pt l 100 m.2 ci kia tng t .Cu 41:Ngun nui cho nhit in tr c c im g? Ti sao c c im ?

Cu 42:C my k thut ni dy cho nhit in tr?

- c 4 cch:1.k thut ni 2 dy2.k thut ni 3 dy3.k thut ni 4 dy4.k thut ni 2 dy vi b bin i tn hiu o.

Cu 43:K thut ni 2 dy c c im g?-Gia nhit in tr v mch o c ni bng 2 dy. Dy dn ni t mch o ti intr nhit c mt in tr nht nh, in tr ny ni tip vi nhit in tr. Vi 2 in trca 2 dy o, mch o s nhn c mt in th cao hn vi in th cn o.trong thct n gy sai s nn t c s dng.

Cu 44:K thut ni 4 dy c c im g?-Hai dy dng cho 1 dng in khng i i qua nhit in tr , hai dy cn li dnglm dy o .in th o c khng b nh hng bi in tr ca dy o v s thay ica n do nhit .Cu 45:K thut ni 3 dy c c im g?

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-hai dy dng cho 1 dng in khng i i qua nhit in tr , 1 dy cn li dng lmdy o .in th o c khng b nh hng bi in tr ca dy o v s thay i can do nhit .Cu 46 :Ti sao khng dng Pt nguyn cht cu thnh nn nhit in tr?

Ch to nhit in tr pha tp c n nh lu di tt hn Pt nguyn cht .Cu 47:Di o nhit ca nhit in tr Pt ph thuc vo yu t no?

- Ph thuc vo nng cht pha tp thm vo Pt.Cu 48:NTC, PTC l g? l cc cm bin tch cc hay th ng?-NTC vit tt ch Negative Temperature Coficient c ngha l in tr c h s nhit m.Bn cht l cc in tr bn dn c i tr gim khi nhit tng. Cm bin th ng-PTC vit tt ca Positive Tenperature Coficient ngha l in tr c h s nhitdng.bn cht l 1 in tr bn dn c in tr tng khi nhit tngC 2 loi trn l cm bin th ng

Cu 49 :Khi lm vic vi dng in nh, NTC c tnh cht g?NTC lm thit b o nhit .Trong TH ny phi lu dng qua NTC phi b hiu ng Jun ko lm NTC nng ln.Cu 50:Khi lm vic vi dng in ln, NTC c tnh cht g?

Dng NTC o mc cht lngKhi dng in ln chy qua NTC s lm n nng ln v in tr ca n gimxung. S thay i in tr ph thuc vo mi trng t n. Nu t NTC trongmi trng khng kh th s suy gim in tr khc vi khi NTC trong mi trngcht lng.

Cu 51:Khi lm vic vi dng in nh, PTC c tnh cht g?

Cu 53:LM 35 c u ra thay i nh th no i vi nhit

u ra ca LM35 l in p hoc dng in thay i t l thun vi nhit thayi theo hm m vi nhit . Thay i theo hm m vi nhit .Cu 54:

Cp nhit in hot ng da trn nguyn l no?Khi c s chnh lch nhit gia 2 u 1 thanh kim loi s pht sinh 1 sc in

ng. Trong cp nhit gm 2 thanh kim loi khc nhau hn 1 u vi nhau gi lu nng, 2 u cn li l u lnh. Khi c chnh lch gia u nng v lnh thsinh ra 1 sut in ng gia 2 u lnh (do 2 kim loi khc nhau)Cu 55:Cp nhit l cm bin tch cc hay th ng?

Cp nhit l cm bin tch ccCu 56:

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Khi ni dy dn cho cp nhit in cn lu u g? Ti saoCn lu : Khi ni dy t cp nhit ti thit b o phi c tnh cht nhn dinging vi kim loi lm cp nhit v nhit ti cc im ni phi hon ton gingnhau v ti cc im ni s to thnh cc cp nhit sinh ra in p k sinh -> gy ranhng sai s

Cu 57:Trong cp nhit in lm th no c c gi tr nhit mi trng ngoi

khng i ?Cu 58:Trong thc t loi cp nhit no c s dng ph binCp nhit loi K vi v bc c th hot ng nhit 1150 o C v c bn theothi gian cao.Tmax dng lin tc 1260o CTmax dng ngn hn 1350 o CThnh phn NTC- Ni

Mu dy theo tin chu M: vng Nht: - xanhCu 59:Mun o nhit ca bnh axit sunfuaric c nng, nn s dng cm bin loai

no?S dng cm bin

Cu 60: o v hin th tc ng c ca t, tu in ngi ta s dng cm bin loino?

Dng my pht tc 1 chiuCu 61:c im ca my pht tc 1 chiu

- My pht tc 1 chiu c tn hiu u ra l tn hiu in p 1 chiu, tn hiu ny ltn hiu tng t v t l vi tc quay.- My pht tc 1 chiu c tn hiu u ra khng hon ton tuyn tnh v n phcthuc vo c tnh t ha ca vt liu t. di tc rt thp in p u ra cacm bin hu nh ko c. di tc cao qu nh mc th in p u ra b boha.Cu 62:My pht tc c th phn bit c chiu quay ko?

Khng th phn bit c chiu quayCu 63:Cm bin tc kiu t tr bin thin

o tc ca c cu quay thng qua i lng in no?Cu 64:S lng bnh rng c ngha nh th no vi di o ca cm bin tc quaykiu t tr bin thin.

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S lng bnh rng quyt nh di o.o tc nh th s bnh rng nhiuo tc ln th s bnh rng t

Cu 65:

Cm bin tc quay kiu t tr bin thin c xc nh c chiu quay ca ccu truyn ng ko?Khng xc nh c chiu quay.Cu 66:

Encoder l g?Thit b o tc quay.Cu 67:Nu cu to v nguyn l ca encoder?

Encoder c 2 loi Encoder tng i v Encoder tuyt i+ Cu to :

- Encoder tng i gm 1 a m gn vi trc quay. Trn a m c to 1 hngl tng ng vi cc vch sng ti. S mch Encoder tng i thng t 100-1000 vch vi tc quay cng chm s vch cng ln.-Encoder tuyt i c cc u ra A,B,C,D mi goc tng ng vi 1 m bt ura.M ca gc dc m ha,s vng m tng ng vi s biet m ha cc gc quay+ Nguyn l hot ngEncoder tng i a ra 3 u ra A,B,Z.Trong u ra A,B s c xung lnhnhau nu o chiu quay u ra z ch c 1 xung ra khi Encoder quay ht 1 vng.Encoder tuyt i c s u ra tng ng vi s bt m ha gc quay.Xung ratng ng vi m ha BCD,gray

Cu 68.c my loi encoder ? s khc nhau gia chng ntn ?C hai loi Encoder :encoder tng i v encoder tuyt i :S khc nhau gia hai loi ny l :Encoder tng i thi khng o c trc tip c gc v khng o dc tc thp quVi Encoder tuyt i th do trc tip c gc v o c tc thp

Cu 69Mun vn tc v xc nh chiu quay ca c cu truyn ng s dng loi cm

bin vn tc no ?cch xc inh chiu quay ?Dng encoder tng i xc nh chiu quay v o dc vn tc ca c cutruyn ngS lch pha 90 ca 2 tn hiu A v B cho php ta xc nh c chiu quayCu 70ng dng ca mi loi Encoder ?

Cu 71c my phng php o p sut ? o l nhng phng php no ?

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Cu 72c th o p sut trc tip dc khng ? ti sao ?

Cu 73Nu nguyn l ca cm bin p sut p sut mng sc co gin kim loi ? l

cm bin tch cc hay th ng ? ti sao ?

Nguyn l ca CB p sut mng sc co gin kim loi l da trn s thay i dintr ca 1 s KL khi bi ko dn hoc nn co li.Khi KL b ko gin n tr nn dihon v mng hn do in tr ca n tng ln, cn khi kl b nn li n tr nnngn hn v dy hn do in tr ca n gim xung. Cn c vo s thay iin tr ca mng sc xc nh lc, p sut ca phn t cn kho sty l cm bin th ng v di tc dng ca p sut mng sc co gin b bindng, u ra ca CB l gi tr in trCu 74Ti sao gi l cm bin p sut mng sc co gin kl ? c my loi cu trc mngsc co gin kl ? c im mi loi ?

Cm bin dng o p sut dc lm bng kl nm trn nn tng cht do v dc chto thnh hnh un khc nh cc sc nn dc gi l CB p sut mng sc KLPhn loi : c 3 loi cu trc mng sc l :

- Mng sc co gin l kl lm bng dy in kl rt mn nm trn 1 n bngcht do, ngi ta thc hin bng phng php in lua hoc quang khc. Vs thay i chiu di thc t rt b cho nn dg dn in ny dc ch tothnh hnh un khc d c chiu di ln trn 1 din tch b, t ta c sthay i in tr ng k

- Mng sc co gin dy: dc ch to trn nn gm vi k tht in la, loi mngdy c nhy k cao v chi nh hng ca nhiu, do do trong thc t loi

mng ny t dc s dng.Cu 75cm bin p sut din tr hot ng theo hiu ng no ? l cm bin tch cchay th ng ? nu c im ca cm bin ny ?Cm bin p sut in tr lm vic da trn hiu ng in tr p in trong bndn : khi tc dng 1 lc c hc ln 1 cht bn dn do cc ng sut c hc trongtinh th bn dn lm cho in tr sut ca bn dn thay iy l cm bin tch ccDc im ca cb p sut in tr.

D nhy cao

s tuyn tnh tt s tr ca p sut v nhit l b thi gian hi p nh cu trc nh gn r tin

Cu 76

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Cm bin p sut p in thch anh hot ng theo hiu ng vt l no? Hiu ng c my loi? cm bin p in thch anh hot ng theo hiu ng no?Cb p in thch anh hot ng da trn hiu ng p in ca vt liu Thch Anh,khi c 1 lc nn c hc ln tinh th thch anh th mt i din ca tinh th thachanh s xut hin cc in tch tri du, lng in tch ny t l thun vi lc tc

dng ln nTy theo hng tc dng ca lc m ta c cb ap din thch anh theo hiu ngchiu di hoc hiu ng chiu ngangCu 77Mun o p sut p nhit 2400 C dng loi cm bin no ph hp?Dng cb p sut in thch anhCu 78mun o lc th phi lm th no?

o lc l do nhng hiu qu m n gy ra, o lc ngi ta c th dng cb mngsc kl,cb in tr p in,cb p in thch anh

Cu 79loadcell l g? N lm vic theo nguyn tc no ?Loadcell l thit b xc inh trng lng ca vt, khi tc ng

Cu 80:Lu lng l g? C my dng lu lng?-luu luong l luong cht lng hay cht kh chy qua tit din ngang ca dng trong mtn vi thi gian.-c 6 loi luu luong:+luu luong k p suat vi sai+luu luong ke in t

+luu luong k siu m+luu luong k tua bin+luu luong k nhit+luu luong ke tit din thay iCu 81:Lu lng cc cht ph thuc vo yu t no ? H s Reynl l g? N nh hng nh thno n vn tc dng chy.Tr li:Lu lng cc cht ph thuc vo di lu lng , nhit , p sut.

- H s Reynol l gi tr khng th nguyn biu th ln tng i gia nhhng gy bi qun tnh v tnh nht n s cn tr i vi dng chy

- H s Reynol cng ln th vn tc dng chy cng nh v ngc li.Cu 82:Lu lng p k Visai hot ng da trn nguyn tc no ? c im ca php ony ?-Da theo nh lut Becnuali, biu din quan h gia luu luong v s bin thin p suatca chat lng trong 1 ng thu hp.khi dng cht lng chy qua 1 l thu ho th tc dng chy sau l s tng ln so vi tc dng chy trc l thu hp , p sut cht lng

8/3/2019 cng o lng

14/15

ca ra gim i v to nn s chnh lch p suat phi truoc v pha sau l. S dng cmbin p k vi sai ta suy ra luu luong-c im :+cu to n gin, chc chn+lm vic ko gy ting n, co th ch to hng lot

+lp t bng mng sc hoc kt ni xen k+gy tn hao luu luong dng chyCu 83 :Nu dng lu lng l cht c hot tnh ha hc mnh th dng lu lng p kVisai c ph hp khng ? ti sao ?

Cu 84 :Lu lng k in t hot ng da trn nh lut no ? Yu cu ca dng chy c

tnh cht g ? c im ca cm bin ny ?-nh lut Faraday. Khi c dng cht lng dn in chy ct qua t trng do cun dyt vung gc vi dng chy th s xuat hin s cm ng trn ha in cc thnh ng.- :+ cho php o luu luong theo 2 chiu+dduong kinh ng c th t 2mm -3m+dng chy c in dn tren 1mS/cmCu 85 :ng dn cht lu c th o lu lng bng lu lng k in t l kim loi hayphi kim ?-phi kimCu 86 :Lu lng k siu m c gy ra tn hao lu lng dng chy khng ? tng chnh xc ca php o bng cm bin ny th phi lm th no ?-ko-s dng nhiu cp cm bin v hin tng phn x nhiu lnCu 87Cng t th tch c nguyn l hot ng nh th no? c im ca php o ny ?-khi cho cht lng chy qua lm quay cc cnh phn ng. Nh b phn m s vngquay c th suy ra th tch cht lng chy qua ng-c im :+cnh th tch dc t trong bung c th tch bit+ chnh xc 0,15-2%+v qun tnh phn ng nn c th gy nn nhm ln trong qu trnh o dao ngCu 88Loi lu lng k no cho php o lu lng 2 chiu?-luu luong k nhitCu 89Cm bin thng minh l g? Tnh nng chnh ca cm bin thng minh?-l s kt hp gia mp v cc mch vi in t vi cc cm bin thng thng thchin cc chc nng mi m cm bin thng thng khng thc hin c.

8/3/2019 cng o lng

15/15

-chng c th thu thp s liu t nhiu i luong do khc nhau, gia cng s b ket qutheo cc thut ton nh trc , c kh nng b sai s do nh hng ca mi trngbn ngoi qua hiu chnh dc sai s cho php o mt khc nh mch vi in t cc cmbin thng minh c kh nng m ha tn hiu o, ghp ni dc vi cc thit b ngoi vi,ghp ni luu tr d liu. Kt hopwj vi mp chng c kh nng thc hin cc php tnhs

i s, iu khin qu trnh o vi cc khu kt hp nh A/D, cc b dn knh MUX...