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Cu1) Khi nim v cm bin? Phn loi cm bin? cc vn khi thit kv s dng cm bin
Tr li:*Khi nim cm bin: Cm bin l thit b dng cm nhn bin i cc i
lng vt l v cc i lng khng c tnh cht in cn o thnh cc i lngin c th o v x l c*Phn loi :+ phn lai theo p ng v kch thch+ phn loi cm bin theo dng kch thch+ phn loi theo nguyn l lm vic: cm bin tch cc v cm bin th ng*cc vn khi thit k v s dng cm bin-Cc i lng nh hng ti cm bin:
Nhit m
p sut, gia tc, rung
T trng-Sai s ca php o: sai s h thng v sai s ngu nhin- nhy ca cm bin- nhanh, thi gian hi p-Gii hn s dng
Cu 2:Cm bin quang hot ng da trn nguyn l g? Ngun sngca cm bin quang 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 htnhn We, lc ny mnh vi cc in t lp trong v yu vi in t lp ngoi,do cc lp in t lp ngoi d tch khi nguyn t. khi nh sng chiu ln
vt cht nu nng lng ca photo ln cp cho in t thng lc lin ktth cc i lng trong vt cht s c gii phng tr thnh in t t do.+ in tch c gii phng do cht sng ph thuc vo bn cht ca vt b
chiu sng.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 u dung nh sng hngngoi.
Cu 3:Ngi ta phn loi cm bin quang da trn nguyn tc no?
c im ca mi loi? Loi no c khong cch pht hin xa nht?Tr li :- Ngi ta phn loi cm bin da trn nguyn tc: phn loi theo ngun snggia 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 mi loi :
+ thu pht c lp: b pht v thu nm cc thit b c lp vi nhau to ra nhsng b thu c cng ln nht, phn bit sng ti cao, pht hin c vt thkhng ph thuc vo mu sc v b mt vt th.
+ cm bin phn x gng: khong cch pht hin ln, kh nng phn bit sngti cao, c th phn bit c vt trong sut, gia r hn cm bin thu pht clp, tin cy cao.
+cm bin loi phn x khuch tn: ch pht hin trong vng gii hn, l tngcho nhiu ng dng cn trit tiu nn.
- loi c khong cch pht hin xa nht l cm bin thu pht c lp.
Cu 4:Nu k hiu ca cm bin quang? Nu r ngha ca cc khiu ?
Tr li:- k hiu v ngha ca cm bin quang:
+ nng lng bc x: Q l nng lng phn x lan truyn hoc bc x didng bc x n v J hoc lm.s
+thng lng nh sng : l cng sut pht x lan truyn hoc hp th. n vW hoc lm.
+ cng nh sng : I l lung nng lng pht theo mt hng di mt nv gc khi. n v W/s hoc Cd.
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+ chi L: l t s gia cng d nh sng phn x bi 1 b mt theo mthng xc nh v din tch ca phn t ny trn mt phng vung gc vihng . n v W/m2 hoc lm/m2
Cu 5:Trn thn cm bin c ghi: Dark on , Light on. iu nghal g?Tr li:- dark on : khi pht hin vt s cho tn hiu off khng c vt cho tn hiu on- light-on : khi pht hin vt s cho tn hiu on , khng c vt s cho tn hiu off.
Cu 6 :Khi mc song song nhiu cm bin quang thu pht tch bit,nn lm th no chng nhiu?
Tr li:- Khi mc song song nhiu cm bin quang thu pht tch bit, chng nhiu ta
phi o tn hiu phn pht v phn thu.
Cu 7:Nu nguyn l hot ng ca cm bin si quang? c imca cm bin si quang?
Tr li :- cm bin si quang l mt dng ca cb quang, nh sng dng trong cb cng lnh sng hng ngoi hoc lazer. nh sng pht ra thit b c dn truyn qua1 si quang a n u pht, nh sng p vo vt th phn x li u thu quasi quang v mch xa l.- c im ca cb quang: pht hienj vt c kch thc nh, thi gian p ngnhanh, pht hin chnh xc ngay c trong khi iu kin khng cn bng. thu phtln ti 1100mm, phn x hin i ln ti 130mm, phn x xc nh pht hin6mm.
Cu 8:Nu nguyn l hot ng ca cm bin laze? c im ca cmbin laze?
- nguyn l hot ng ca cm bin laze : cb gm phn t pht lazer, phn tcm nhn v gng. Ngun sng pht ra gng 1 phn, v chiu vo i tng.sng phn hi t i tng s giao thoa vi sng pht ra. Nu cc nh sng
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trng nhau th sng giao thoa c bin gp i bin ban u. nu sng phnhi lch pha 180 th bin sng giao thoa =0.- c im : ngun sng lazer rt n sc, nh hng cao, c kh nng truyn rtxa do thng lm cb phn bit mu, nhn bit hnh dng sn phm.
Cu 9:Trong cc loi cm bin quang, loi no c kh nng pht hin kch thcvt th, loi no c kh nng pht hin vt th gc khut, loi no pht hin vtc h s hp th nh sng ln, nh?Tr li:--Loi c kh nng pht hin vt th gc khut l cm bin thu pht tch bit vcm bin phn x gng.
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Cu 10:Trong cc thit b iu khin t xa, phn t nhy sng l g?Tr li:-L phototransistor
Cu 11:Nu c im ca cng tc hnh trnh? Nu ti l rle xoay chiu th cth s dng cng tc hnh trnh ng/ ngt c khng? Nu cch u ni tivi tip im thng m?Tr li:-N l 1 cng tc t hi,thng thng c 1 chn chung com, c 1 tip im thngng v 1 tip im thng m tc ng vo cng tc hnh trnh khi va vo vtthng s dng 1 n by c gn vng bi gim ma st khi tip xc vi vt-Cng tc hnh trnh l 1 tip im c kh do tui th khng cao , khng cdng trong mi trng du, m, ha cht-Nu ti l rle xoay chiu th c th s dng cng tc hnh trnh ng ngt.-Cch u :
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Cu 12:Nu cu to ca cng tc t? V k hiu ca cng tc t? Trong thc tc cng tc t dng tip im thng ng khng? Nu c th cu to ca nnh th no?Tr li :
-Cu to ca cng tc t gm c 1 tip im li g c t trong 1 bng thy tinhrt chn khng v 1 nam chm vnh cu . Khi tip im li g t gn nam chmvnh cu th lc t trg do nam chm sinh ra s ht tip im ng li.-K hiu :
-Trong thc t ko c cng tc t dng tip im thng ng.
Cu 13:Nu c im ng dng ca cng tc t?Tr li :-Cng tc t c tip im t trong bng thy tinh kn nn c th chu c mitrng du, m, ha cht.Trong thc t, cng tc t c ng dng nhiu trong cngnghip 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 ph bin nhn bit
v tr ca pitton 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 nhhng ca nhiu no nht? cch khc phc?Tr li :-c im :u d ca cm bin thng c dng l mch t h lm bng li sthoc Ferit. Trn mch t c cun dy in t .
Nu c 1 vt kim loi dn in ni kn mch khe t h th gi tr in cm ca ud in cm s gim , dng in tiu th tng nu cp u d cm bin 1 in pxoay chiu.*khong cch pht hin ca cm bin tim cn in cm ph thuc vo kch thc,hnh dng vt th v dn t ca vt th, nhit mi trng*Cm bin chu nh hng ca nhiu
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*Khc phc :bc v kim loi v dn xung t.
Cu 15:cm bin tim cn in dung c c im g? Khong cch pht hin cacm bin tim cn in dung ph thuc vo yu t no? Cm bin chu nh
hng ca nhiu no nht? cch khc phc?Tr li :-u cm bin c lm bng 2 ming kim loi mng, mi ming c S= 1cm2, dncch in trn cng 1 mt phng to thnh 2 in cc trn cng 1 mt phng . Cm
bin tim cn in dung c th xc nh c tt c cc vt c hng s in mi khcvi mi trng in mi ngoi khng kh, xc nh c mc tn s thay i*Khong cch pht hin ca cm bin in dung ph thuc vo m v sngca mi trng.
-Cm bin chu nh hng ca nhiu t mi trng xung quanh nh nhit psutgy ra sai lch tn hiu hi p,tn hiu o,dn n tui th cm bin gim-Cch khc phc : +/Gim cc nh hng ca cc i lng tc ng vo cm binnh cch in,chng rung,chng t trng..
+/S dng s ghp ni gim nh hng cc i lngnhiu nh s dng cu in tr
Cu 16:Mun pht hin vt th hoc cht liu ng trong hp kn ths dng cm bin no? C yu cu g khng?
Tr li:- Mun pht hin vt th hoc cht liu ng trong hp kn th s
dng cm bin tim cn in 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 loicm bin no? Khong cch ti a t cm bin n vt th l baonhiu?
Tr li :- Mun nhn bit vt th kim loi n gn c th s dng loi cm
bin tim cn in cm
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- Khong cch ti a t cm bin n vt th l 1cm.
Cu 18:C th s dng cm bin tim cn in dung lm cm bin omc 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 mc- Yu cu c th o c:+ i vi cht lng cch in: dt hai in cc kim loi thng ngtrong bnh cha dung dch trong bnh chnh l in mi+ i vi cht lng dn in: s dng cb in dung gn ln thnh bnh+ o lin tc dng 2 que o, 1 que o c bc cch in bng lpin m, mt que o khng bc cch in.
Cu 19: c th o c lu lng cht lng bng lu lng k int, yu cu v cht lng y nh th no?
Tr li :- c th 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.
Cu 20:V cch u ni vi ti ca cm bin tim cn in cm c ura kiu NPN?
Tr li:
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Cu 21:V cch u ni vi ti ca cm bin tim cn in cm c u rakiu PNP?
Tr li:
Cu 22:Cm bin tim cn in dung l cm bin tch cc hay thng? ti sao?
Tr li:- cb tim cn in dung l cb tch cc v n c s bin i nng
lng. khi c mt vt kim loi n gn nng lng ca b daong b tiu hao to nn cc dng in xoy c cm ng bntrong vt th.
Cu 23:Cm bin tim cn in cm l cm bin tch cc hay thng? ti sao?
Tr li:- cb tim cn in cm l cb th ng- v: u ra khng mang tnh cht in, in dung thay i, in p k
thay i.
Cu 24:Trong cc loi cm bin tim cn, loi no pht hin xa nht?Tr li :
- cb tim cn : + cng tc hnh trnh
+ cm bin in cm in dung+ cb tim cn cng tc t+ cb quang cng nghip
- trong cc loi cb tim cn th cb quang cng nghip l pht hin xanht.
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Cu 25:Cm bin siu m hot ng da trn nguyn tc no? Nu cim ca cm bin siu m?Tr li :-nguyn tc ca cb siu m : ngi ta dng 1 mch to sng m vi tn s tmkhong 300khz. Nhng mi ln pht n ch pht 8 chu k xung mu ca sng msau i tn hiu phn hi v u thu.Mch thu sng m s kim sot 8 chu k xung mu thu v xc nh c nhiu
hay tn hiu phn hi sau chuyn thnh xung vung. B vi x l c gn trncb siu m s xc nh khong cch gia sn ln ca xung pht lnh o khongcch vi sn ln ca xung thu v tnh ra thi gian gia thi im pht v nhnsng siu m, sau nhn vi vn tc truyn sng =340m/s-c im ca cb siu m:
+ khong cch bt vt ln t 2mm ti trc mt thm tr hang trm mt.+ 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 o ngng hay o lin tc?
Tr li :- Cm bin mc kiu phao c kh thng c ng dng trong cng
nghip ha cht hoc ch bin du m, trong h thng bm nc tng cho nh cao tng.
- N dng o ngng.-
Cu 27:Yu cu cht lng ca cm bin mc kiu in dn l g?Tr li:
- Yu cu cht lng ca cm bin mc kiu in dn l: ch ngdng o cc cht lng dn in khng c tnh n mn v khng
ln cc vt th cch in nh du, nht
Cu 28:Mun o 3 ngng trong bnh v bng nha dng cm binmc kiu in dn th cn my in cc?
Tr li :
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- Mun o 3 ngng trong bnh v bng nha dng cm bin mckiu in dn th 4 in cc: Po l cc gc c t st y thng.Cc cc cn li P1,P2,P3 c gn cc v tr m ta cn xc nhmc.
Cu 29:Mun o 3 ngng trong bnh v bng inox dng cm binmc kiu in dn th cn my in cc?
Tr li:- Mun o 3 ngng trong bnh v bng inox dng cm bin mc
kiu in dn th cndng 3 in cc v cc gc Po lc ny cgn ngay trn thnh bnh bng kim loi do vy ch cn dng 3 ccP1,P2,P3.
Cu 30:Ngun nui cho cc in cc ca cm bin mc kiu in dnc c im g? Ti sao?
Tr li:- ngun nui cho cc in cc ca cb mc kiu in dn c dc im
l: ngun nui 10=> 24v xoay chiu.- v t tn hao khi cc in cc nm trong mi trng m t v d
n mn.(dng 1 chiu gy hin tng in phn tn hao nhiu,
d n mn in cc)Cu 31:Khi o mc cht lng cch in 1 cch lin tc bng phng
php thay i in dung, ngi ta xc nh mc thng qua hnh thcno?
Tr li:- Khi o mc cht lng cch in 1 cch lin tc bng phng php
thay i in dung, ngi ta xc nh mc bang cch: t 2 incc kim loi ca cb thng ng trong bnh cha dung dch, nh vykhi dung dch trong bnh tng hay gim s lm cho din tch bncc thay i lm cho in dung gia hai bn cc cng thay itheo. Sau dng 1 mch in t xc nh s thay i ca indung suy ra mc cht lng trung bnh
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Cu 32:Khi o mc cht lng dn in 1 cch lin tc bng phngphp thay i in dung, ngi ta xc nh mc thng qua hnh thcno?
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 queo, 1 que o c bc bng 1 lp in mi, 1 que khng bc chtin. khi mc cht lng thay i s lm din tch mt ngoi ca 2que o thay i lm in dung thay i nenn ngi ta xc nhc mc cht lng trong bnh
Cu 33:Khi mun o mc cht lng c hot tnh ha hc mnh, dngcm bin loi g th ph hp?
Tr li :- Khi mun o mc cht lng c hot tnh ha hc mnh, ngi ta
thng dng loi cb bc x nh cb tia f, cb sng siu m, cb mcx quang hc.
Cu 34:Cm bin mc kiu phao bin tr c ng dng u? Cmbin cho u ra lin tc hay ngng?
Tr li:- cb mc kiu phao bin tr c ng dng ch th mc xng, du trong cc
bnh cha nhin liu ca t, xe my- cb cho u ra 1 cch lin tc.
Cu 35:Cm bin mc kiu in dung l tch cc hay th ng? Tisao?
Tr li :- cm bin mc in dung l cb th ng- v:
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Cu 36:C my phng php o nhit ? l phng php no?Tr li:- c 4 phng php o nhit :
- cc phng php o nhit :+ dng nhit in tr kim loi+ dng IC cb nhit + dng nhit in tr NTC,PTC+ dng cp nhit
Cu 37:Mun tng chnh xc ca php o, cn phi lm g?Tr li:
- mun tng chnh xc ca php o cn gim hiu s nhit gia nhit mitrng o v nhit ca cb gim nh nht.- c 2 phng php: + tng trao i nhit gi cb v mi trng o
+ gim trao i nhit gia cb v moi trng ngoi
Cu 38:Mun o nhit ca vt rn cn lm nh th no?- Mun o nhit ca vt rn: t b mt ca vt ngi ta khoan 1 l nh ngknh R v su L
- l ny a cb vo su trong vt rn tng chnh xc cn phi m bo 2iu kin:
+ L>= 10+ khong trng gia v cb v thnh l khoan phi c lp y bng vt liu
dn in tt.
Cu 39:Nhit in tr l g?Tr li:
- Nhit in tr l in tr thay i theo s nhit ca n Rt=f(t),o Rt c th suy ra nhit
- Nhit in tr kim loi l 1 cb nhit lm vic da trn s thayi i tr ca 1 s kim loi khi nhietj thay i.
-Cu 40) Thng s Pt-100, Pt -500, Pt 1000 c ngha nh th no?
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Tr li:Pt-100: ngha l cm bin lm bng platin c Ro= 100Pt -500: ngha l cm bin lm bng platin c Ro= 500Pt 1000: ngha l cm bin lm bng platin c Ro= 1000
Ro : in tr cm bin 0 C
Cu 41 : Ngun nui cho nhit in tr c c im g? Ti sao c c im?Tr li :-L ngun in p thp, 1 chiu, n nh-V:trnh hiu ng Jun lm nhit in tr b nng ln
Cu 42 :c my k thut ni dy cho nhit in tr?Tr li :C 4 k thut ni dy o cho nhit in tr :-Ni 2 dy- Ni 3 dy- Ni 4 dy- Ni 2 dy vi b bin i tn hiu o
Cu 43 : K thut ni 2 dy c c im g?Tr li :Gia nhit in tr v mch o c ni bng 2 dy. Dy dn ni t mch o tiin tr nhit c 1 in tr nht nh, in tr ny ni tip vi nhit intr.Vi 2 in tr ca 2 dy o, mch o s nhn c 1 in th co hn vi inth cn o
trong thc t phng php ny gy sai s ln nn t sd
Cu 44 : K thut ni 4 dy c c im g?Tr li :-c im ca kt ni 4 dy: cho kt qu o tt nht-Dng 2 dy cho 1 dng in khng i i qua nhit in tr, 2 dy cn lidng lm que o
Cu 45 :K thut ni 3 dy c c im g?
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Tr li :-Vi cch ni ny 2 mch o c hnh thnh,1 trong 2 c dng lm chun.-K thut 3 dy sai s ca php o do in tr dy o v s thay i ca n donhit ko cn. Tuy nhin k thut 3 dy yu cu 3 dy o phi c cng tr s
k thut v cng nhit Trong thc t kt 3 dy o l kt rt ph bin.
Cu 46:Ti sao khng dng Pt nguyn cht cu thnh nn nhit in tr?Tr li:-Chi ph cao-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?Tr li:-Ph thuc vo nng cht pha thm vo Pt
Cu 48 : NTC, PTC l g? l cc cm bin tch cc hay th ng?Tr li :-NTC (Negative Temperature Coficient) :l cm bin nhit c h s thay i nhitm. Tc l khi nhit tc ng tng th lm cho tr khng ca cm bin gim.
-PTC (Positive Temperature Cofficient): l cm bin nhit c h s thay i nhitdng tc l khi nhit tc ng tng lm cho tr khng tng.
Hai loi cm bin trn u l cm bin th ng.
Cu 49 : Khi lm vic vi dng in nh, NTC c tnh cht g?Tr li :+Khi lm vic vi dng in b,ngta c th dng NTC lm thit b o nhit .Trong trng hp ny phi lu dng qua NTC phi b hiu ng Junkhng lm cho NTC b nng ln
Cu 50 :Khi lm vic vi dng in ln, NTC c tnh cht g?Tr li :+Khi lm vic vi dng in ln, NTC c dng o mc cht lng.
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-Khi cho dng in ln chy qua NTC s lm cho NTC nng ln v in tr can gim xung. S thay i ca in tr ph thuc vo mi trg t n, nu ttrong mi trng khng kh th s suy gim in tr khc vi khi t trong mitrg cht lng
Cu 51 :Khi lm vic vi dng in nh, PTC c tnh cht g?Tr li :
-Khi lm vic vi dng in nh th gy ra sai s thang o ln v khi nhit intr trong PTC thay i khng ng k,khi dng nh th khng c hiu ng Jun
Cu 52 :Khi lm vic vi dng in ln, PTC c tnh cht g?Tr li :
Cu 53 :LM35 c u ra thay i nh th no vi nhit ?Tr li :
-IC loi LM35 c u ra l in p hay dng in thay i t l thun trc tip vicng thang o.(Thay i theo hm s m vi nhit ). in p ng ra l10mV/ C v sai s khng tuyn tnh l +_1,8mV cho ton thang o.
Cu 54 :Cp nhit in hot ng da trn nguyn l no?Tr li :
-u cm bin nhit l 2 thanh dn in khc loi c hn kn 1 u gi l unng, 2 u cn li l u lnh.lm vic theo nguyn tc nhit in. Ngha l khiu ni b tc ng nhit th 2 u cn li to ra in p 1 chiu
Cu 55 :cp nhit in l cm bin tch cc hay th ng?Tr li :-Cp nhit l cm bin tch cc
Cu 56 :Khi ni di dy dn cho cp nhit in, cn lu iu g? Ti sao?Tr li :
-Cn lu : khi ni dy t cp nhit ti thit b o phi c tnh cht nhit inging vi kim loi lm cp nhit v nhit ti cc im ni phi hon tonging nhau.
V : ti cc im ni s to thnh cc cp nhit sinh ra in p k sinh gy ranhiu sai s
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Cu 57 :Trong cp nhit in, lm th no c c gi tr nhit mi trngngoi khng i?
Tr li :Cu 58 :Trong thc t, loi cp nhit in no c s dng ph bin nht?
Tr li :-Trong thc t hin nay cp nhit kiu K c s dng ph bin nht vi v bc nc th hot ng nhit 1150 C v c bn theo thi gian cao+ max dng lin tc :+ max dng ngn hn:+Thnh phn : NiCr-Ni
+Mu dy theo tnh cht M :
Dy + :vng
Dy- :+Mu dy theo tnh cht Nht :
Dy + :
Dy- : xanh dt
Cu 59 :Mun o nhit ca bnh axit Sufuaric c nng, nn s dng phngphp no?Tr li :
Cu 60 : o v hin th tc ng c ca t, tu in, ngi ta s dng cmbin loi no?Tr li :-Cm bin tc dng my pht tc 1 chiu
Cu 61 :c im ca my pht tc 1 chiuTr li :-My pht tc 1 chiu c tn hiu u ra l tn hiu in p 1 chiu, tn hiu ny
l tn 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 phthuc vo c tnh t ha ca vt liu t. di tc rt thp in p u raca cm bin hu nh khng c. di tc cao qu nh mc th in p ura b bo ha
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Cu 62 :My pht tc 1 chiu c th phn bit c chiu quay hay khng?Tr li :-Khng th phn bit c chiu quay
Cu 63 :Cm bin tc kiu t tr bin thin o tc ca c cu quay thngqua i lng in no?
Tr li :-Tn s ca sc in ng
Cu 64 :S lng bnh rng c ngha nh th no vi di o ca cm bin tc quay kiu t tr bin thin
Tr li :
-S lng bnh rng quyt nh di o o tc nh th s bnh rng nhiu
o tc ln th s bnh rng it
Cu 65 :Cm bin tc quay kiu t tr bin thin c xc nh c chiu quayca c cu truyn ng khng?
Tr li:-khng xc nh c chiu quay
Cu 66:Encoder l g?Cu 67:Nu cu to v nguyn l ca encoder?Tr li:-Encoder c 2 loi: encoder tuyt i v encoder tng i+Cu tao :
Encoder tng i :gm 1 a m v 3 cp thu pht quang, a m cgn vi trc quay t do.Trn a m c to 1 hng l tng ng vi ccvch sng ti.c t 100-1000 l ty thuc vo ti thp hay cao, v3 cp thu pht quang ni vi 3 phn t khuch i thut ton a ra 3xung tng ng vi u A, u B v u Z. Trong cc v tr A,B,Z lv tr t cp thu pht hng ngoi.
Encoder tuyt i : c phn cu to tng t encoder tng i nhngtrn a m c nhiu vng m v u ra ca encoder tuyt i l cc t
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m nh phn tng ng vi cc gc quay c th l m A,B,C,D hayGray v tng ng vi nhiu cp thu pht hng ngoi , s cp thu phthng ngoi s tng ng vi s bit ca 1 m.V s m ca 1 gc s cnh = (n :l s gc c m ha)
+Nguyn l hot ng: Encoder tng i : a ra 3 u ra A,B,Z. Trong u ra A,B s c xung
lch nhau nu o chiu quay, u ra Z ch c 1 xung ra khi encoder quayht 1 vng
Encoder tuyt i :c s u ra tng ng vi s bit m ha gc quay.xungra tng ng vi m BCD, Gray
Cu 68 :C my loi encoder? S khc bit gia chng nh th no?
Tr li :-c 2 loi encoder :encoder tuyt i v encoder tng i-S khc bit gia 2 loi :+Encoder tng i : ch c 1 hng l quang , s l quang trong 1 vng t 100-1000 l ch o c tc quay c 3 u ra+Encoder tuyt i :c nhiu hng l o xung , u ra c 3 dng A,B,Z o c ctc quay v gc quay
Cu 69 :Mun o vn tc v xc nh chiu quay ca c cu truyn ng sdng loi cm bin vn tc no? Cch xc nh chiu quay?Tr li :-Dng encoder tng i xc nh chiu quay v o c vn tc ca c cutruyn ng.-Cch xc nh chiu quay :tng ng vi phng php t cc cp thu pht hngngoi vo v tr A,B,Z th xung ra u A s sm pha hn u B nu tc ngquay l quay thun v s xung u ra tng ng vi s l m trn vngquay.Khi quay ht 1 vng th u ra Z s sut ra 1 xung , mch s l encoder scn c vo gin xung xc nh tc quay v chiu quay
Cu 70 :ng dng ca mi loi Encoder?Tr li :
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-Encoder tng i : o tc ng c, xc nh tc quay v chiu quay,o lu lng, o dn, qung g i-Encoder tuyt i :c kh nng o gc quay tng ng vi tc quay chm
Cu 71 :C my phng php o p sut? l nhng phng php no?Tr li :-C 3 phng php o p sut
o p sut vi sai
o mng kim loi
o mng cng l xo
Cu 72 :C th o p sut trc tip c khng? Ti sao?
Tr li :-Khng th o p sut trc tip(tuyt i)-V : khng c so ngng mc = 0
Cu 73:Nu nguyn l ca cm bin p sut mng sc co gin kim loi? lcm bin tch cc hay thu ng? Ti sao?Tr li:-Nguyn l ca cm bin p sut mng sc co gin kim loi l da trn s thay i
in tr ca 1 s kim loi khi b ko dn hoc nn co li.Khi kim loi b ko dn ntr nn di hn v mng hn do in tr ca n tng ln , cn khi kim loi bnn co li n tr ln ngn hn v dy hn do in tr ca n gim xung.Cn c vo s thay i in tr ca mng sc xc nh lc, p sut ca phn tcn kho st
y l cm bin th ng v di tc dng ca p sut mng sc co gin b bindng . u ra ca cm bin l gi tr in tr
Cu 74:Ti sao gi l cm bin p sut mng sc co gin kim loi? C my loicu trc mng sc? c im mi loiTr li:-Cm bin c dng o p sut, c lm bng kim loi v nm trn 1 nn bngcht do v c ch to thnh hnh un khc nh cc sc nn c gi l cb p sutmng sc kim loi
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-C 3 loi cu trc mng sc l: Mng sc co gin l kim loi:thng l nhng ng dy in bng kim loi
rt mn nm trn 1 n bng cht do.g dn in ny c ch to thnh hnh
un khcc s thay i in tr ng k Mng sc co gin mng mng:c ch to theo phng php bc hi chn
khng hay cng ngh phun bi , vi phng php ny mng sc s ccmng do nhy ca mng cao v it b nh hng ca nhit
Mng sc co gin mng dy:c ch to trn nn gm vi k thut in la , c
dy ko cao v chu nhiu nh hng ca nhiutrong thc t t c sdng
Cu 75:Cm bin p sut in tr hot ng theo hiu ng no? l cm bintch cc hay th ng? Nu c im ca cm bin ny?
Tr li:-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 trong tinhth bn dn lm cho in tr sut ca bn dn thay i
y l cm bin th ng-c im:
nhy cao
S tuyn tnh tt
S tr ca p sut v nhit u b Thi gian hi p nh
Cu trc nh gn
R tin
Cu 76: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 ngno?
Tr li:-Cm bin p sut p in thch anh (Si02) lm vic da trn hiu ng p in cavt liu thch anh : khi tc dng mt lc nn c hc ln tinh th thch anh th ccmt i din ca tinh th thch anh s xut hin cc in tch tri du , lng intch ny s t l thun vi lc nn tc dng
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-C 2 loi: hiu ng theo chiu di hoc hiu ng theo chiu ngang ty theo hngtc dng ca lc vi v tr trc tinh th thch anh-Cm bin p in thch anh ngy nay hu ht l da vo hiu ng ngang
Cu 77:Mun o p sut p nhit 2400C dng loi cm bin no ph hp?Tr li:-Dng cm bin p sut p in thch anh
Cu 78:Mun o lc th phi lm th no?Tr li:-o lc l o nhng hiu qu m n gy ra, o lc ngta c th dng cb mngsc kim loi, cm bin p in hoc cm bin p in thch anh
Cu 79:Loadcell l g? N lm vic theo nguyn tc no?Tr li:-Loadcell l thit b xc nh trng lng ca vtKhi b tc ng lc cell cm bin b bin dng lm gi tr in tr u ra cm binthay i t l vi bin dng . Da vo bin dng xc nh trng lng cavt
Cu 80:Lu lng l g? C my dng lu lng?Tr li:-Lu lng l lng l lng cht chy trong mi trng truyn dn trong 1 n vthi gian (1s).-C 3 dng lu lng l lu lng cht lng, cht kh v hi ncCu 81:Lu lng cc cht ph thuc vo nhng yu t no? H s Reynol l
g? N nh hng nh th no n vn tc dng chy ?Tr li :-Lu lng cc cht ph thuc vo di lu lng, nhit , p sut cn o.
-H s Reynol l 1 gi tr khng th nguyn biu th ln tng i gia nhhng gy bi qun tnh
Cu 82 :Lu lng p k Visai hot ng da trn nguyn tc no ? c imca php o ny ?Tr li :
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-Lu lng p k vi sai hot ng da theo nh lut Becnuali, biu din quan hgia lu lng v s bin thin p sut ca cht lng trong 1 ng thu hp.-c im :
Cu to n gin, chc chn
Lm vic khng gy ting n, c th ch to hng lot Lp t bng mng st hoc ni xen k.
Gy tn hao lu lng dng chy.
Cu 83 :Nu dng lu lng l cht c hot tnh ha hc mnh th dng lulng p k Visai c ph hp khng ? ti sao ?
Tr li :-Khng
V : gy hin tng n mn g ng dn ln
Cu 84 :Lu lng k in t hot ng da trn nh lut no ? Yu cu cadng chy c tnh cht g ? c im ca cm bin ny ?Tr li :-Lu lng k in t hot ng da theo nh lut Faraday. Khi c dng cht lngdn in chy ct qua t trg do cun dy t vung gc vi dng chy th s xuthin sc in ng cm ng trn 2 in cc thnh ng.
-Yu cu ca dng chy : dng chy c in dn trn 1mS/cm.-c im :
Cho php o lu lng 2 chiu.
Dng knh ng c th t 2mm n 3m.
dng chy c in dn trn 1mS/cm.Cu 85 :ng dn cht lu c th o lu lng bng lu lng k in t lkim loi hay phi kim ?Tr li :
-L phi kim
Cu 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 ?Tr li :-Lu lng k siu m khng gy ra tn hao lu lng dng chy
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- tng chnh xc c th s dng nhiu cp cm bin v hin tng phn xnhiu ln.
Cu 87 :Cng t th tch c nguyn l hot ng nh th no? c im ca
php o ny ?Tr li :-Cng t th tch l thit b o s lng th tch cht lng i qua 1 bung cha
bit th tch . Khi c cht lng chy qua lm quay cnh phn ng. Nh b phnm s vng quay c th suy ra th tch cht lng chy qua ng.-c im :
chnh xc 0,15 -2 %.
V qun tnh ng nn c th gy nhm ln trong qu trnh o ng .
Cu 88 :Loi lu lng k no cho php o lu lng 2 chiu?Tr li :- Lu lng k in t
