TRNG I HC K THUT CNG NGHIPKHOA IN T

BO CO THC TP TT NGHIP

THIT K V THI CNG MCH TO DAO NG CU WIEN DNG IC KTT

Gio vin hng dn: TS. Nguyn Phng Huy Sinh vin thc hin: Nguyn Vn Thuy MSSV: DTK0951030133 Lp: K45KDT01

THI NGUYN 2014

TRNG HKTCN CNG HA X HI CH NGHA VIT NAM KHOA IN T c lp - T do - Hnh phc

BN NHN XT BO CO THC TP TT NGHIP(Dng cho ging vin hng dn)- H v tn sinh vin : Nguyn Vn Thuy- M s SV: DTK0951030133- Lp: K45KDT01- Chuyn ngnh: K thut in t- Gio vin hng dn: Nguyn Phng Huy- B mn, khoa: K thut in t- Nhn xt:................................................................................................................................................................................................................................................................................................ ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................- Ti ng (khng ng ) cho sinh vin ................................... c thng qua Bo co thc tp tt nghip trc b mn.Thi Nguyn, ngy thng nm 2014Ngi nhn xt(K tn v ghi r h v tn)

MC LC1. Tng quan v mch to dao ng cu Wien2 1.1. C s l thuyt.....21.2. Gii ng thiu v mch dao cu Wien..32. S nguyn l mch to dao ng cu Wien53. S m phng ..64. Thit k v thi cng mch in...8Kt lun..10Ti liu tham kho.11

M UYu cu quan trng ca mt k s tt nghip ngnh K thut in t ngoi vic nm vng kin thc chuyn mn cn phi vn dng cc k nng hc c, p dng vo thc t gii quyt cc bi ton c th. i vi mi bi ton cn thit phi thc hin theo ng trnh t thit k. Bt u t vic phn tch s nguyn l, tnh ton thng s ca cc linh kin, m phng kim chng v cui cng l thit k v lp rp mch in. Mi cng on u phi c thc hin mt cch ng b, chnh xc.Nhm p ng cc yu cu trn, c s hng dn ca Thy : Nguyn Phng Huy, em la chn chuyn thc tp tt nghip vi tiu Thit k v thi cng mch to dao ng cu Wien dng IC KTT. Ni dung bo co gm cc mc chnh nh sau: 1. Tng quan v mch to dao ng cu Wien: Phn ny gii thiu v khi nim mch cu Wien,c s l thuyt mch khuch i hi tip,dao ng dch pha,Op-Amp.ng thi cng trnh by nguyn l chung ca cu Wien.2. S nguyn l mch cu Wien: a ra s nguyn l, la chn, tnh ton thng s ca cc linh kin cho bi ton mch cu Wien s dng IC 741.3. S m phng: Dng phn mm Multisim v v phn tch hot ng ca mch m phng v s bin i ca cc tn hiu trong mch.4. Thit k mch in: S dng phn mm Altium Designer thit k mch in.Cui cng l phn kt lun v ti liu tham kho.Em xin chn thnh cm n Thy :Nguyn Phng Huy cng cc Thy, C trong b mn K thut in t tn tnh ging dy, ch dn, gip em hon thnh bo co thc tp tt nghip.Thi Nguyn, ngy .. thng .. nm 2014 Sinh vin thc hin Nguyn Vn Thuy

1.Tng quan v mch to dao ng cu Wien1.1.C s l thuyt Mch dao ng cu Wien l: mt dng dao ng dch pha , thng dng Op-Amp rp theo kiu khuch i khng o.-Dao ng dch pha : +Cn c gi l mch dao ng RC. +Gm hai phn chnh l h thng khuch i v h thng hi tip. +C th dng BJT ,FET, hoc Op-Amp.-Op-Amp :l linh kin in t ph bin,cu to cn bn gm mt u vo vi sai, ng ra l mt ngun p ph thuc.Op-Amp thng c dng thit k cc mch khuch i,vi phn,tch phn,Op-Amp hot ng bng ngun i c ni tng ng vi hai ng vo Vcc+ v Vcc- .Op-Amp 741 l mt trong nhng loi thngc s dng hnh 1.

-Mch khuch i hi tip - Nuphaca vflch 1800so vi vsta c hi tip m.

- Nuphaca vfcng pha vi vs(hay lch 3600) ta c hi tip dng.

1.2 Gii thiu v mch dao ng cu WienMch dao ng cu Wien l: mt dng dao ng dch pha , thng dng Op-Amp rp theo kiu khuch i khng o.Hnh 2

iu kin v nguyn l hot ng :Ta c h s hi tip

Nu chn R1 = R2 = R ; C1 = C2 =C

Khi no hoc th ta c

Ta c trong hnh 2 li vng h Nu R4 =2R3 th ta c Av =3Trong mch hnh 2 ta ch : - Nu li vng h Av< 3mch khng dao ng.- Nu li vng h Av>> 3 th tn hiu dao ng nhn c b bin dng.V vycch tt nht l khi khi ng, mch to Av> 3 ( d dao ng) xong gim dn xung gn bng 3 c th gim thiu ti a vic bin dng.2.S nguyn l mch to dao ng cu WienNguyn l mch to dao ng cu Wien c ch ra trong mch hnh 3

Hnh 3 Mch to dao ng cu WienCc thnh phn yu cu :-in tr ( 2 in tr 1k v 1 in tr 100k)-Chit p (2 chit p 1k v 1 chit p 100k)-T (0.1F x2)-741 Op ampNguyn l : Cc tn hiu phn hi trong mch dao ng ny c kt ni vi cc thit b u cui u vo khng o ngc cc op-amp hot ng nh mt b khuch i khng nghch o. Cc iu kin khng chuyn giai on xung quanh cc mch c thc hin bng cch cn bng cu, khng giai on chuyn i l iu cn thit cho cc dao ng bn vng. Tn s ca dao ng l tn s cng hng ca cu cn bng v c cho bi biu thc fo = 1 / 2RC Ti tn s cng hng (o), cc nghch o v khng o ngc in p u vo s c bnh ng v "trong giai on" cc tn hiu phn hi tiu cc s b hy b do s phn hi tch cc lm cho mch dao ng. T vic phn tch cc mch, c th thy rng cc yu t phn hi = 1/3 tn s dao ng.V vy cho dao ng duy tr, cc b khuch i phi c li vng h l 3 c th gim thiu ti a vic bin dng.-Trong mch to dao ng hnh 3 tn s c th thay i. Tn s ca mch trn c th c thay i bng cch ch n gin l thay i chit p R1 v bin ca dng sng c th c iu chnh bng cch thay i chit p R. Tn s ca sng sin c to ra trong mch trn ph thuc vo cc thnh phn R1, R2, C1 v C2.i vi vic iu chnh bin ca sng sin c thc hin bng cch s dng chit p.Mt trit p gi tr thp (1K) c kt ni vi gi tr cao (100K) iu chnh th c th c thc hin vi cc in tr c gi tr cao v iu chnh tt vi cc in tr c gi tr thp.

3.S m phngSau khi thit k mch nguyn l, ta tin hnh xy dng mch m phng dng phn mm Multisim kim chng.

Hnh 4.S m phng mch to dao ng cu Wien

Hnh 5 Dng sng u ra4.Thit k v thi cng mch in

Hnh 5. Mch nguyn l

Hnh 6. Mch in 2d Hinh7. Hnh nh tht

Kt lunBo co trnh by quy trnh thit k v thi cng mch to dao ng cu Wien dng IC KTT.Cc kt qu t c c th :-Tm hiu tng quan v mch cu Wien, tp chung phn tch v nguyn l ca mch cu Wien.-La chn phng n xy dng mch nguyn l, tnh ton la chn cc thong s cho mch.-Kho st mch thit k qua cng c m phng Multisim-Thit k mch in dng phn mm Altium DesignerMc d c gng, song do iu kin v thi gian v kinh nghim thc t cn nhiu hn ch nn khng th trnh khi thiu st. V vy, em rt mong nhn c s ng gp kin ca cc thy c cng nh ca cc bn b quan tm. Em xin chn thnh cm n Thy :Nguyn Phng Huy cng cc Thy, C trong b mn K thut in t tn tnh ging dy, ch dn, gip em hon thnh bo co thc tp tt nghip. Sinh vin thc hin Nguyn Vn Thuy

TI LIU THAM KHO1.Phm Minh H, K thut mch in t, NXB, KHKT, 19972.http://www.circuitsgallery.com/2012/08/wien-bridge-oscillator.html3.http://www.engineersgarage.com/tutorials/diy-circuit-design-waveform-clamping4.http://websrv1.ctu.edu.vn/coursewares/cntt/machdt/lythuyet/ch10/ch10.htm#M12

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