Mach Cam Bien Khoi

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TI THIT K MCH IN T TNG T : MCH CM BIN KHI, T NI CNG CNG. KHI C NGI HT THUC TRONG PHNG TH CHUNG REO

LI NI UNgy nay, con ngi cng vi nhng ng dng ca khoa hc k thut tin tin ca th gii, chng ta v ang ngy mt thay i, vn minh v hin i hn. S pht trin ca k thut in t to ra hng lot nhng thit b vi cc c im ni bt nh s chnh xc cao, tc nhanh, gn nhl nhng yu t rt cn thit gp phn cho hot ng ca con ngi t hiu qu ngy cng cao hn. in t ang tr thnh mt ngnh khoa hc a nhim v. in t p ng c nhng i hi khng ngng ca cc ngnh, lnh vc khc nhau cho n nhu cu thit yu ca con ngi trong cuc sng hng ngy. Mt trong nhng ng dng ca rt quan trng ca ngnh cng ngh in t l cc mch cm bin vi cc linh kin tch hp cao. Mch cm bin c ng dng rt nhiu trong cng nghip v cc lnh vc khc trong cuc sng vi nhng thit b iu khin t xa rt tinh vi v t c nng sut, kinh t tht cao . Xut pht t nhng ng dng , chng em thit k mt mch ng dng nh l mch cm bin khi. V thi gian, ti liu v trnh cn hn ch nn vic thc hin n cn nhiu thiu st Knh mong nhn c s ch dn v gp tn tnh ca tt c qu thy cng cc b

MC LCTrang LI M U2 PHN THIT K CHNH PHN I:NGUYN TC THIT K V S KHI...4 I) Nguyn tc thit k ..........................................................5 II) S khi .......................5 PHN II:S NGUYN L, CHC NNG TNG KHI7 I) Chc nng tng khi.7 II) S khi ton mch...8 III) Nguyn l hot ng...9 PHN III: CC LINH KIN S DNG TRONG MCH I) in tr 11 II) T in.12 III) Transistor13 IV) iot-led...14 V) IC LM1801...15 VI) iot 1N4004....16

VII) TIC 106M...17 VIII) LDR ..20 IX) Chung v HP126 PHN IV:NH GI U NHC IM CA MCH .26 PHN V:KT LUN .28

PHN I : NGUYN TC THIT K V S KHII)NGUYN TC THIT K Mch cm bin khi thng c s dng trong cc h thng bo ng tin tin. Hu ht cc thit b ny s dng chuyn nghip kh-d, ion ha phng hoc cc yu t phng x nh cc cm bin.C hai cch c bn thit k b cm bin khi. Cch th nht s dng nguyn tc ion ha. Ngi ta s dng mt lng nh cht phng x ion ha trong b cm bin. Khng kh b ion ha s dn in v to thnh mt dng in chy gia hai cc c np in. Khi cc phn t khi lt vo khu vc cm nhn c ion ha s lm tng in tr trong bung cm nhn v lm gim lung in gia hai cc. Khi lung in gim xung ti mt gi tr no th b cm bin pht hin v pht tn hiu bo ng. Cch th hai s dng cc linh kin thu pht quang. Ngi ta dung linh kin pht quang (LED, LED hng ngoi ) chiu mt tia nh sang qua vng bo veejvaof mt linh kin thu quang (photo diode, quang tr, photo transistor).

Khi mt v chy xy ra hoc khi c ng x c gi ht th huc trong phng th khu vc s xut hin khi vi mt cao. Khi c chy, kh i ngan qua vn bo v s v c hi ng ng s che chn hoc lm gim c nh sng chiu vo linh kin thu. K cng m ng h Khi gim xu ung ti mt gi tr n th b cm bin s pht h v ph tn hiu b no b hin t bo ng. Tron hai cch ny th ph ng h hng php th nht nhy hn v hiu qu hn nh p u ng kh th thi v lp t. Cn cch th h tuy t nh hn nh c p hai hy hng linh k d ki kin m v d th thi. Li dng c im ny chng em chn cch hai thi k mch hc c m h it h cm bi khi v s dng b phn thu pht chnh l LDRs v mt LE n h ED

II) S KH MCH C BIN KHI : M N

PHN II: CHC NNG TNG KHI, S NGUYN L V NGUYN L HOT NGI) CHC NNG TON KHI 1) Khi cm bin : c nhim v bin i tn hiu khi thnh tn hiu in, trong phn thit k ny ta dng quang tr. Nh ta bit hot ng ca quang tr l: khi c nh sang chiu vo in tr ca n gim i ng k so vi khi khng c chiu sng. 2) Khi n nh in p ngun Khi ngun ly ngun AC_ 220V t in li gia nh,dng bin th h p xung 12Vol_AC, khi qua cu chnh lu c DC_ 12V, dng IC 7805 p cung cp 2 mc in p cho ton mch l +12vol v +5vol.

Hoc ta cng c th ly trc tip sc in thoi dng lm ngun cho mch

3) Khi khuych i : i M khuyc i c nh ch ch him v kh huych i tn hiu t b c bin k i in cm khi v a r tn hiu iu ch q khi b ng pht tn h bo ra qua o hiu ng. Tro ti ny, mch khuych c s dng l IC LM1801 IC LM18 ong n i C 1. 801 ny bao gm khi khuych thut to v b s snh so snh vi h in p o i i on so hai tham ch so sn tn hiu vo v tn hiu in mt c hiu nh u i chiu. 4) Khi bo ng : to ra thanh b ng i g m boII) S NGUYN L : S nguyn l ton mc : ch

III) NGUYN L HOT NG : LM1801 l mt IC c ng dng c bit, c thit k c bit cho cc my d khi, cung cp cho chng ta xy dng mch ny bng cch s dng s lng ti thiu ca cc thnh phn. N bao gm mt trong nhng ngun cung cp zener ni b, hai kt qu u ra in p tham chiu, mt in p so snh, v in p u ra transistor l 500mA. Vi mch c kt ni vi ngun in trc tip. iot D1 chnh lu ngun in xoay chiu v in tr R7 lm gim n n mc m cc mch c th hot ng vi t in C2 n nh in p v zener bn trong IC iu chnh n. Hai LDRs ng nht c ni theo kiu cu sao cho kt ni ny bo v v ngn chn nhng s thay i nhit v ha gi nhng hiu ng tc ng ln mch. V vy R13 LDR v LED phi c t theo mt cch sao cho khi c cc ht khi thuc xm nhp vo n s tc ng ln b mt LDRs v lm gim nh sng trn LDR ng thi lm thay i in tr ca n. Mt khc R12 LDR v LED phi c t lin k nhau v khng c khng kh lu thng xy ra. Nh vy khi thuc l s khng c gy nh hng n R12 v in tr ca n khng b bin i. Cch tt nht lm iu , l t R12 v LED trong mt hp ring bit. P1 l in p hiu chun. HP1 l mt m thanh bo ng my pht in. Dng in u ra tc ng ln h thng bo ng bn ngoi. Khi thc hin so snh v pht hin s chnh lch in p gia hai LDRs n tc ng ln bng bn dn Th1 v kt qu l bt u bo ng,

PHN IV: CC LINH KIN S DNG TRONG MCH

I) in tr : in tr l mt linh kin c tnh cn tr dng in v lm mt s chc nng khc ty vo v tr in tr trong mch in. Cu to: in tr c cu to t nhng vt liu c in tr sut cao nh lm bng than, magie kim loi Ni-O2, oxit kim loi, dy qun. biu th gi tr in tr. Ngi ta dung cc vng mu biu th gi tr in tr. K hiu:

Hnh dng thc t:

Cch c tr s in tr 4 vng mu: Gi tr in tr thng c th hin qua cc vch mu trn thn in tr, mi mu i din cho mt s. Mu en: s 0, mu nu: s 1, mu : s 2, mu cam: s 3, mu vng: s 4, mu lc: s 5, mu lam s 6, mu tm s 7, mu xm: s 8, mu trng: s 9. Nhn trn thn in tr, tm bn c vch mu nm st ngoi cng nht, vch mu v vch mu th hai, k n c dng xc nh tr s ca mu.. Vch th ba l vch xc nh nhn t ly tha: 10(gi tr ca mu) . Gi tr ca in tr c tnh bng cch ly tr s nhn vi nhn t ly tha Gi tr in tr = tr s x nhn t ly tha) - Phn cui cng: (khng cn quan tm nhiu)lvch mu nm tch bit vi ba vch mutrc, thng c mu hong kim hoc mubc, dng xc nh sai s ca gi tr intr, hong kim l 5%, bc l 10%. y chng ta s dng iot 1N4004 II) T in: T in l linh kin c kh nng tch in. T in cch in vi dng in mt chiu v cho dng in xoay chiu truyn qua. T in c chia lm hai loi chnh: loi khng phn cc v loi c phn cc.

Loic phn cc thng c gi tr ln hn loi khng phn cc, trn hai chn ca loi phn cc c phn bit chn ni m, ni dng r rng, khi gn t c phn cc vo mch in, nu gn ngc chiu m dng, t phn cc c th b h v hot ng sai. Ngoi ra ngi ta cn gi tn t in theo vt liu lm t, v d: t gm, t giy, t ha... Hnh dng: t in c kh nhiu hnh dng khc nhau.

K hiu: c k hiu l

C

Biu tng trn mch in:

n v ca t in - n v ca t in l Fara, 1 Fara c tr s rt ln v trong thc t ngi ta thng dng cc n v nh hn nh + P(Pico Fara) 1 Pico = 1/1000.000.000.000 Fara (vit gn l 1pF) + N(Nano Fara) 1 Nano = 1/1000.000.000 Fara (vit gn l 1nF) + MicroFarra 1 Micro = 1/1000.000 Fara (vit gn l 1F)

=> 1F = 1000nF = 1.000.000 Pf III) Tranzitor:

K hiu : transistor NPN

Q1

Q2

Transistor PNP Cu to: bi 2 tip xc P-N ghp lin tip gm cc vng bn dn loi P v N xp xen k nhau, vng gia c tnh cht dn in khc vi 2 vng ln cn v c b rng rt mng khong 10A0 m nh to ln tip xc P-N gn nhau. Nu vng gia l N ta c transistor PNP, ngc li nu vng gia l vng P ta c transistor NPN.

IV) Diode_Led -Diode thng -Led quang: quang tr, quang diode v quang transistor, nng lng ca nh sng chiu vo

cht bn dn v cp nng lng cho cc in t vt di cm. Ngc bli khi mt in t t di dn in rt xung di ho tr th s pht ra mt nng lng E=h.f Di dn in Di ha tr Di cm hf. Khi phn cc thun mt ni P-N, in t t do t vng N xuyn qua vng P v ti hp vi l trng (v phng din nng lng ta ni cc in t trong di dn in c nng lng cao ri xung di ho tr - c nng lng thp v kt hp vi l trng), khi ti hp th sinh ra nng lng. i vi diod Ge, Si th nng lng pht ra di dng nhit. Nhng i vi diod cu to bng GaAs (Gallium Arsenide) nng lng pht ra l nh sng hng ngoi (khng thy c) dng trong cc mch bo ng, iu khin t xa). Vi GaAsP (Gallium Arsenide phosphor) nng lng pht ra l nh sng \vng hay . Vi GaP (Gallium phosphor), nng lng nh sng pht ra mu vng hoc xanh l cy. Cc Led pht ra nh sng thy c dng lm n bo,trang tr Phn ngoi ca LED c mt thu knh tp trung nh sng pht ra ngoi.

c nh sng lin tc, ngi ta phn cc thun LED. Tu theo mc nng lng gii phng cao hay thp m bc sng nh sng pht ra khc nhau s quyt nh mu sc ca LED. Thng thng, LED c in th phn cc thun cao hn it thng thng, trong khong 1,5 2,8V tu theo mu sc pht ra, mu : 1,4

1,8V, v ng: 2 2, ,5V, cn m xanh l cy: 2 2 mu 2,8V, v d in q LED t a ng qua i khong vi mA. i c s dng tron mch ny l iot 1 iot ng 1N4004 V) LDR Rs LD hay i tr ph thuc nh sng. N c tc dng c bit t DRs n c g trong mch h cm bi sng ti. thng th n . ng gi tr in tr c mt LD l rt cao, c khi cao ca DR n 100 00000 , nhng khi chng b k n khch thch bi nh s th gi tr in tr h ng ca n s gim m cch t ngt. s t t

VI) IC LM1801: LM1801 c dng IC, c thit k c bit cho cc my d khi, cung cp cho chng ti xy dng mch ny bng cch s dng s lng ti thiu ca cc thnh phn. N bao gm mt trong nhng ngun cung cp zener ni b, hai kt qu u ra in p tham chiu, mt in p so snh. LM1801 thc hin so snh nng lng thp vi dng in cao , u ra m v thu tn hiu. Hin nay ngi ta dng IC LM1801 trong ngnh ch to nh: thit b chng trm, thit b pht hin r r nc, r r kh t, nhng mch n p, ngun pin c vn hnh theo di Mt s thng s chnh ca LM1801: Dng in cung cp thng l dng 7A , nhng khi n iu khin cng so snh th in p u ra ca transistor ln ti 500mA Ti : Rset = 10m , V+= 9v, Ta = 25c R1 + R2 = 10m n nh.

VII) TIC 106M

IX) CHUNG BO NG ,HP HP l my pht to m thanh , khi c xung tn hiu a n to dao ng cho chung rung to m thanh ng thi cng tc ng n HP to ra m thanh nghe rt kch thch. Dng in u ra tc ng h thng chung bo ng bn ngoi.

PHN IV:NH GI U,NHC IM CA MCH*U IM:

_Mch n gin,d thc hin_Cc linh kin d mua trn th trng. _C nhy tng i cao v tuyn tnh. _ng dng: iu khin t xa l ci iu khin t