GVHD: Nguyn Vn Cng

Li M u: Ngy nay, khi nim k thut s tr thnh quen thuc vi nhiu ngi, bi v s pht trin ca ngnh k thut s ny c nh hng rt ln n ngnh kinh t ton cu. C ngi nu ln tng gi nn kinh t ca thi i chng ta l nn kinh t k thut s , s ha gn nh vt khi ranh gii ca mt thut ng k thut . Nh c u im ca x l s nh tin cy trong truyn dn, tn a thch nghi v kinh t ca nhiu phn mm khc nhau, tn tin li trong iu khin v khai thc mng. S ha ang l xu hng pht trin tt yu ca nhiu lnh vc k thut v kinh t khc nhau. Khng ch trong lnh vc thng tin lin lc v tin hc. Ngy nay, k tht s v ang thm nhp mnh m vo K thut in t, iu khin t ng, pht thang truyn hnh, y t, nng nghipv ngay c trong cc dng c sinh hot gia nh. Ngay t nhng ngy u khai sinh, k thut s ni ring v ngnh in t ni chung to ra nhiu bc t ph mi m cho cc ngng kinh t khc v cn m bo c yu cu ca ngi dng c v cht lng v dch v. ng thi kin thc v k thut s l khng th thiu i vi mi sinh vin, nht l sinh vin in t. V nh mi ngi nhn thy rng, ngy nay trt t giao thng nc ta ang ri ren. V vy vic s dng n giao thng ti nhng giao l l rt cn thit v hiu r hn v nguyn l hot ng v mun pht trin thm v m hnh ny, em chn ti cho n 1 l nghin cu v n Giao Thng .Thc hin bng cc IC 555,4017 kt hp mt s n led hin th v mt s t cng nh in tr to xung nhp. Vi vic s dng cc b IC trn ta c th thc hin n giao thng vi cc b m bt k. I.S nguyn l mch: 1/S khi

B to xung

B m

B gii m hin th

B hin th

B ngun

Mch gm c 5 khi: - B to xung - B m - B gii m hin th - B hin thTrang 1

GVHD: Nguyn Vn Cng

- B ngun 2/ Chc nng cc khi 2.1/ B ngun: B ngun cung cp cho ton b mch y ta dng ngun mt chiu khong 5V cung cp cho b to xung IC555 v b m IC 74190 . 2.2 / B to xung: Dng IC 555 to ra xung nhp. Cu to IC 555

U 7 5 4 6 2 8 N D

1 S C HO GU 3 T

C V R S T T H R T R G V C E C 5 5 5 G N 1 D

*S to xung nhp:

*Chu k to xung: Thng thng trong mch dao ng ta c cng thc tnh thi gian ngng dn ca transistor l : T = RCln2 =0.693 RCTrang 2

GVHD: Nguyn Vn Cng

Thi gian ngng dn mc p cao cng l lc t C2 np d.ng qua R1+R2 Tn = 0.693*(R1+R2)*C2 Thi gian ngng dn mc p thp cng l lc t C2 x d.ng qua R2 Tx = 0.693*R2*C2 Nh vy chu k ca tn hiu s l : T = Tn+Tx T = 0.693*(R1+2*R2)*C2 . Vi mch nh th LM 555 l mch tch hp Analog- digital. Do c ng vo l tn hiu tng t v ng ra l tn hiu s. Vi mch nh th LM555 c ng dng rt rng ri trong thc t, c bit trong lnh vc iu khin, v nu kt hp vi cc linh kin R, C th n c th thc hin nhiu chc nng nh: nh th, to xung chun, to tn hiu kch, hay iu khin cc linh kin bn dn cng sut nh Transistor, SCR, Triac *S chn LM555 Chn s 1 : (GND) Cho ni mass ly dng cp cho IC , dng in t mas chy vo IC. Chn s 2: (Trigger Input ) Ng vo ca mt tng, y mc p chun bng 1/3 Vcc, ly cu phn p to bi ba in tr 5K.Khi mc p chn 2 xung n mc (1/3)Vcc th chn 3 s chuyn ln mc cao, lc ny kha in t trn chn s 7s h. Chn s 3: (Output) Ng ra tn hiu dng xung (mc p khng thp th cao). Chn s 4 :(Reset) Xc lp trng thi ng ra .Khi chn s 4 cho ni mass th chn s 3 cht mc p thp , ch khi chn s 4 t mc p cao th ng ra chn 3 mi c t do v mi c th lc cao lc thp. Chn s 5:(Control Voltage) Chn iu khin ,chn ny lm thay i cc mc in p chun trn trn cu chia volt. Chn s 6: (Threshold) Ng vo ca mt tng so vi p 1.C mc p chun bng 2/3 Vcc. Chn s 7: (Dirchange) Chn x in, chn ny l ng ra ca mt kha in (tranistor) kha in ny ng m theo mc p chn s 3. Khi chn 3 mc p cao th kha in ng li v cho dng chay qua, ngc li th kha in h v ct dng. Chn s 8: (+Vcc) Chn ngun ni vo ngun nui Vcc cp in cho IC 555. Bn trong vi mch 555 c hn 20 transistor v nhiu in tr thc hin cc chc nng nh hnh 2 gm c: a) Cu phn p gm ba in tr 5k ni t ngun +Vcc xung mass cho ra hai in p chun l 1/3 Vcc v 2/3 Vcc. b) OP-AMP (1) L mch khuch i so snh c ng In- nhn in p chun 2/3 Vcc, cn ng In+ th ni ra ngoi chn 6. Ty thuc in p caTrang 3

GVHD: Nguyn Vn Cng

chn 6 so vi in p chun 2/3 Vcc m OP-AMP (1) c in p ra mc cao hay thp lm tn hiu R (reset), iu khin Flip- Flop (F/F). c) OP-AMP (2) L mch khuch i so snh c ng In+ nhn in p chun 1/3 Vcc, cn ng In- th ni ra ngoi chn 2. Ty thuc in p chn 2 so vi in p chun 1/3 Vcc m OP-AMP (2) c in p ra mc cao hay thp lm tn hiu S(set), iu khin Flip Flop (F/F). d) Mch Flip-Flop(F/F) l loi mch lng n kch mt bn. Khi chn set (S) c in p cao th thin p ny kch i trng thi ca F/F ng Q ln mc cao v ng Q xung mc thp. Khi ng set ang mc cao xng mc thp th mch F/F khng i trang thi. Khi chn Reset(R) c in p cao th in p ny kch i trng thi ca F/F lm ng Q ln mc cao v ng Q xung mc thp. Khi ng Reset ang mc cao xung thp th mch F/F khng i trng thi.

hnh 2 : Cu trc bn trong ca LM 555 e) Mch Output l mch khuch i ng ra tng khuch i dng cp cho ti. y l mch khuch i o, c ng vo l chn Q ca F/F, nn khi Q mc cao th ng ra chn 3 ca IC s c in p thp ( 0V), v ngc li, khi Q mc thp th ng ra chn 3 ca IC s c in p cao ( Vcc). f) Transistor T1 c chn E ni vo in p chun khong 1,4 V, l loi Transistor PNP. Khi cc B ni ra ngoi bi chn 4, c in p cao hn 1.4V, th T1 ngng dn, nn T1 khng nh hng m hot ng ca mch. Khi chn 4 c in tr tr s nh thch hp ni mass th T1 dn bo ha, ng thi cng lm mch OUTPUT dn bo ha, v ng ra xung thp. Chn 4 c gi l chn Reset c ngha l n Reset IC 555 bt chp tnh trng cc ng vo khc. Do , chn Reset dng kt thc xung ra sm khi cn. Nu khng dng chc nng Reset th ni chn 4 ln Vcc trnh mch b Reset do nhiu.Trang 4

GVHD: Nguyn Vn Cng

g) Transistor T2 l transistor c cc C h ni ra chn 7 ( Discharge = x ). Do cc B c phn cc bi mc in p ra Q ca F/F, nn khi Q mc cao th T2 bo ha v cc C ca T2 coi nh ni mass. Lc , ng ra chn 3 cng mc thp. Khi Q mc thp th T2 ngng dn cc C ca T2 b h, lc , ng ra chn 3 c in p cao. Theo nguyn l trn, cc C ca T2 ra chn 7 c th lm ng ra ph c mc in p ging mc in p ca ng ra chn 4. *Nguyn l hot ng: K hiu 0 l mc thp bng 0V, 1 l mc cao gn bng VCC. Mch FF l loi RS Flip-flop, Khi S = [1] th Q = [1] v Khi R = [1] th = [ 0]. = [0]. Sau , khi S = [0] th Q = [1] v = [1] v Q = [0].

Tm li, khi S = [1] th Q = [1] v khi R = [1] th Q = [0] bi v = [1], transisitor m dn, cc C ni t. Cho nn in p khng np vo t C, in p chn 6 khng vt qu V2. Do li ra ca Op-amp 2 mc 0, FF khng reset. Giai on ng ra mc 1: Khi bm cng tc khi ng, chn 2 mc 0. V in p chn 2 (V-) nh hn V1(V+), ng ra ca Op-amp 1 mc 1 nn S = [1], Q = [1] v = [0]. Ng ra ca IC mc 1. Khi = [0], transistor tt, t C tip tc np qua R, in p trn t tng. Khi nhn cng tc ln na Op-amp 1 c V- = [1] ln hn V+ nn ng ra ca Opamp 1 mc 0, S = [0], Q v vn khng i. Trong khi in p t C nh hn V2, FF vn gi nguyn trng thi . Giai on ng ra mc 0: Khi t C np tip, Op-amp 2 c V+ ln hn V- = 2/3 VCC, R = [1] nn Q = [0] v V = [1]. Ng ra ca IC mc 0. khng i gi tr, t C x in thng qua = [1], transistor m dn, Op-amp2 c V+ = [0] b hn V-, ng ra ca

Op-amp 2 mc 0. V vy Q v transistor.

Kt qu cui cng: Ng ra OUT c tn hiu dao ng dng sng vung, c chu k n nh 2.3 /B m: Dng IC 74190 b m thp phn *S cu to:Trang 5

GVHD: Nguyn Vn Cng

: 2.4/B gii m:

2.5/B hin th: B hin th l thit b th hin s m, v thit b hin th b n giao thng

S th hin s m

Hin th n giao thng

*S Lc V Cc Linh Kin Chnh Trong Mch. a) My bin p My bin th hay my bin p l thit b in gm hai hoc nhiu cun dy, hay 1 cun dy c u vo v u ra trong cng 1 t trng. Cu to c bn caTrang 6

GVHD: Nguyn Vn Cng

my bin th thng l 2 hay nhiu cun dy ng cch in c qun trn cng 1 li st hay st t ferit. My bin th c th thay i hiu in th xoay chiu, tng th hoc h th, u ra cho 1 hiu in th tng ng vi nhu cu s dng. My bin th ng vai tr rt quan trng trong truyn ti in nng. My bin th hot ng tun theo 2 hin tng vt l:

dng in chy qua dy dn to ra t trng (t trng) s bin thin t thng trong cun dy to ra 1 hiu in th cm ng (cm ng in)

Dng in c to ra trong cun dy s cp khi ni vi hiu in th s cp, v 1 t trng bin thin trong li st. T trng bin thin ny to ra trong mch in th cp 1 hiu in th th cp. Nh vy hiu in th s cp c th thay i c hiu in th th cp thng qua t trng. S bin i ny c th c iu chnh qua s vng qun trn li st. Khi NP, UP, IP, P v NS, US, IS, S l s vng qun, hiu in th, dng in v t thng trong mch in s cp v th cp (primary v secondary) th theo nh lut Faraday ta c: v

Nu S = P th

,

ngoi ra

Nh vy b) T in:

T in mt chiu, hay t phn cc (Electrolytic Capacitor): Khi u ni phi ng cc m - dng. Thng trn t quy c cc m bng cch sn mt vch mu sng dc theo thn t, hoc khi t cha ct th chn di hn l cc dng.

Trang 7

GVHD: Nguyn Vn Cng

T in xoay chiu: hay t khng phn cc

T in l mt linh kin th ng cu to ca t in l hai bn cc bng kim loi ghp cch nhau mt khong d gia hai bn t l dung dch hay cht in mi cch in c in dung C. c im ca t l cho dng in xoay chiu i qua, ngn cn dng in mt chiu. Cng thc tnh in dung ca t: C = .S/d l hng s in mi S l in tch b mt t m2 d l b giy cht in mi T in phng gm hai bn phng kim loi din tch t song song v cch nhau mt khong d. Cng in trng bn trong t c tr s E=

l hng s in mi tng i ca mi trng; i vi chn khng 1, giy tm du = 3,6, gm = 5,5; mica = 4 5

0 = 8.86.10-12

0

C2/ N.m2 l hng s in mi ca chn khng.

=

c) in tr: in tr l linh kin th ng c tc dng cn tr c dng v p. in tr c s dng rt nhiu trong cc mch in t. R =/S hoc R=U/I Trong l in tr sut ca vt liu S l thit din ca dy. l chiu di ca dy.

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GVHD: Nguyn Vn Cng

d) Diode:

Diode c cu to gm hai lp bn dn p-n c ghp vi nhau. Diode ch hot ng dn dng in t cc anot sang catot khi p trn hai chn c phn cc thun (VP>VN) v ln hn in p ngng. Khi phn cc ngc (VP