n Ng T ng v Bo Thc N NG T NG CNG VI CHC NNG BO THC Mch in ny s t ng bt n ng khi tri ti, v n s t ng tt khi tri sng nh 1 b cm bin nh sng t nhin vo mi bui sng . y 1 LED pht nh sng trng c dng nh 1 n ng. Ngoi ra n cn c 1 chc nng l t ng bo thc bng m thanh khi b cm bin nhn c nh sng t nhin vo mi bui sng.

Ngun in cung cp cho mch ny c gi tr khong 9V, c ly ra t 1 my bin th. u vo l ngun in xoay chiu 220V- 230V_50Hz , sau n qua bin p gim p ngun(AC) . Ngun AC c chnh lu nh 1 b chnh lu cu gm 4 diode 1N4007: D1,D2,D3,D4 , b chnh lu ny chuyn t dng AC thnh DC. u ra mch chnh lu ta lp thm 1 t in C1 nhm mc ch lc phng tn hiu DC va c chnh lu , v y l t ngun nn c gi tr kh ln (10-3 F).

IC 7806 iu chnh gi mc in p DC n nh khong 6V. Ngoi ra trong mch ny cn c thm ngun nui bng pin hoc cqui (9V) lm nhim v cung cp nng lng cho mch in khi ngun chnh b h, chc nng chnh l ngun d phng. Khi ngun chnh lm vic bnh thng th ngun d phng ny s c np y qua diode D5 v in tr R1 . Khi ngun chnh b h hay mt in th ngay lp tc ngun d phng s cp in cho mch , m bo mch hot ng bnh thng. Diode D5 c nhim v ngn cn hin tng x in ngc v ngun chnh, cn D6 th gi vai tr ng dn DC t pin n phn cn li ca mch. Cc quang tr (LDR) gi chc nng cm nhn nh sng trong phng ng ca bn. in tr ca cc quang tr ny rt ln khi tri ti v in tr thay i kh nhanh,rt nh khi c chiu sng. y LDR1 cm nhn bong ti cn LDR2 th cm nhn nh sng vo mi sng sm. B phn chnh ca mch l IC2 NE555, c chc nng 1 b to dao ng (to xung vung). IC 2 hot ng khi c xung kch t chn s 2 ca IC2. Mt ln kch th u ra chn s 3 s chuyn ln mc cao v s tr v gi tr ban u nu ta kch tr li chn s 2 ca IC2. Khi tri ti th in tr ca LDR1 c gi tr khong 280 kilo-ohms, in tr ca LDR1 tng do cng chiu sng gim. LDR1 v R1 ng vai tr phn p cho chn s 2, LDR1 tng n 1 gi tr no th IC2 hot ng, to dao ng, u ra s 3 ca IC s chuyn ln mc in p cao v kt qu l n LED pht sng. Khi LDR1 c chiu sng bng nh sng trong phng th in tr ca n s gim xung rt thp , n gi b pht xung mc in p dng. Kt qu l u ra s 3 ca IC 2 s chuyn v mc thp v n white LED s tt . Bng cch thay i gi tr ca t C2 ta c th nh thi gian m ca n LED.LDR2 c ghp vi cc linh kin khc to thnh 1 b bo

thc bng m thanh. LDR2 s d nh sng xung quanh phng v gi tr ca n s gim khi mt tri ln (cng chiu sng bt u tng ). in tr ca n gim n 1 mc no th c dng in ln chy qua chn B ca transistor T1(BC548) v kch T1 dn .Khi T1 dn IC nhc UM66 c cp ngun (ly t chn E ca T1) v hot ng, IC 2 l IC nhc nn n s pht ra cc giai iu. Cc giai iu to ra t IC2 c khch i bi transistor T2, sau a ra loa. Nh vy ta c 1 ng h bo thc vi nhng giai iu yu thch m bn c th la chn tu .

in tr R7 c tc dng hn dng cho IC3, cn diode zener ZD th gi nhim v n p cho IC3 trong mc an ton khong 3.3V . PHN DIOT1 Cht bn dn1.1 - Cht bn dn l g ? Cht bn dn l nguyn liu sn xut ra cc loi linh kin bn dn nh Diode, Transistor, IC m ta thy trong cc thit b in t ngy nay. Cht bn dn l nhng cht c c im trung gian gia cht dn in v cht cch in, v phng din ho hc th bn dn l nhng cht c 4 in t lp ngoi cng ca nguyn t. l cc cht Germanium ( Ge) v Silicium (Si) T cc cht bn dn ban u ( tinh khit) ngi ta phi to ra hai loi bn dn l bn dn loi N v bn dn loi P, sau ghp cc ming bn dn loi N v P li ta thu c Diode hay Transistor. Si v Ge u c ho tr 4, tc l lp ngoi cng c 4 in t, th tinh khit cc nguyn t Si (Ge) lin kt vi nhau theo lin kt cng ho tr nh hnh di.

Cht bn dn tinh khit . 1.2 - Cht bn dn loi N * Khi ta pha mt lng nh cht c ho tr 5 nh Phospho (P) vo cht bn dn Si th mt nguyn t P lin kt vi 4 nguyn t Si theo lin kt cng ho tr, nguyn t Phospho ch c 4 in t tham gia lin kt v cn d mt in t v tr thnh in t t do => Cht bn dn lc ny tr thnh tha in t ( mang in m) v c gi l bn dn N ( Negative : m ).

Cht bn dn N 1.3 - Cht bn dn loi P Ngc li khi ta pha thm mt lng nh cht c ho tr 3 nh Indium (In) vo cht bn dn Si th 1 nguyn t Indium s lin kt vi 4 nguyn t Si theo lin kt cng ho tr v lin kt b thiu mt in t => tr thnh l trng ( mang in dng) v c gi l cht bn dn P.

Cht bn dn P

2 Diode (i t) Bn dn2.1 Tip gip P N v Cu to ca Diode bn dn. Khi c c hai cht bn dn l P v N , nu ghp hai cht bn dn theo mt tip gip P N ta c mt Diode, tip gip P -N c c im : Ti b mt tip xc, cc in t d tha trong bn dn N khuych tn sang vng bn dn P lp vo cc l trng => to thnh mt lp Ion trung ho v in => lp Ion ny to thnh min cch in gia hai cht bn dn.

Mi tip xc P N => Cu to ca Diode . * hnh trn l mi tip xc P N v cng chnh l cu to ca Diode bn dn.

K hiu v hnh dng ca Diode bn dn. 2.2 - Phn cc thun cho Diode. Khi ta cp in p dng (+) vo Ant ( vng bn dn P ) v in p m (-)

vo Katt ( vng bn dn N ) , khi di tc dng tng tc ca in p, min cch in thu hp li, khi in p chnh lch gi hai cc t 0,6V ( vi Diode loi Si ) hoc 0,2V ( vi Diode loi Ge ) th din tch min cch in gim bng khng => Diode bt u dn in. Nu tip tc tng in p ngun th dng qua Diode tng nhanh nhng chnh lch in p gia hai cc ca Diode khng tng (vn gi mc 0,6V )

Diode (Si) phn cc thun Khi Dode dn in p thun c gim mc 0,6V

ng c tuyn ca in p thun qua Diode * Kt lun : Khi Diode (loi Si) c phn cc thun, nu in p phn cc thun < 0,6V th cha c dng i qua Diode, Nu p phn cc thun t = 0,6V th c dng i qua Diode sau dng in qua Diode tng nhanh nhng st p thun vn gi gi tr 0,6V . 2.3 Phn cc ngc cho Diode. Khi phn cc ngc cho Diode tc l cp ngun (+) vo Katt (bn dn N), ngun (-) vo Ant (bn dn P), di s tng tc ca in p ngc, min cch in cng rng ra v ngn cn dng in i qua mi tip gip, Diode c th chiu c in p ngc rt ln khong 1000V th diode mi b nh thng.

Diode ch b chy khi p phn cc ngc tng > = 1000V 2.4 Phng php o kim tra Diode

o kim tra Diode

t ng h thang x 1 , t hai que o vo hai u Diode, nu : o chiu thun que en vo Ant, que vo Katt => kim ln, o chiu o kim khng ln l => Diode tt Nu o c hai chiu kim ln = 0 => l Diode b chp. Nu o thun chiu m kim khng ln => l Diode b t. php o trn th Diode D1 tt , Diode D2 b chp v D3 b t Nu thang 1K m o ngc vo Diode kim vn ln mt cht l Diode b d. 2.5 ng dng ca Diode bn dn . * Do tnh cht dn in mt chiu nn Diode thng c s dng trong cc mch chnh lu ngun xoay chiu thnh mt chiu, cc mch tch sng, mch gim p phn cc cho transistor hot ng . trong mch chnh lu Diode c th c tch hp thnh Diode cu c dng .

Diode cu trong mch chnh lu in xoay chiu .

3 Cc loi Diode3.1 - Diode Zener * Cu to : Diode Zener c cu to tng t Diode thng nhng c hai lp bn dn P - N ghp vi nhau, Diode Zener c ng dng trong ch phn cc ngc, khi phn cc thun Diode zener nh diode thng nhng khi phn cc ngc Diode zener s gim li mt mc in p c nh bng gi tr ghi trn diode.

Hnh dng Diode Zener ( Dz )

K hiu v ng dng ca Diode zener trong mch.

S trn minh ho ng dng ca Dz, ngun U1 l ngun c in p thay i, Dz l diode n p, R1 l tr hn dng.

Ta thy rng khi ngun U1 > Dz th p trn Dz lun lun c nh cho d ngun U1 thay i. Khi ngun U1 thay i th dng ngc qua Dz thay i, dng ngc qua Dz c gi tr gii hn khong 30mA. Thng thng ngi ta s dng ngun U1 > 1,5 => 2 ln Dz v lp tr hn dng R1 sao cho dng ngc ln nht qua Dz < 30mA.

Nu U1 < Dz th khi U1 thay i p trn Dz cng thay i Nu U1 > Dz th khi U1 thay i => p trn Dz khng i. 3.2 - Diode Thu quang. ( Photo Diode ) Diode

thu quang hot ng ch phn cc nghch, v diode c mt ming thu tinh nh sng chiu vo mi P N , dng in ngc qua diode t l thun vi cng nh sng chiu vo diode.

K hiu ca Photo Diode

Minh ho s hot ng ca Photo Diode 3.3 - Diode Pht quang ( Light Emiting Diode : LED ) Diode pht phang l Diode pht ra nh sng khi c phn cc thun, in p lm vic ca LED khong 1,7 => 2,2V dng qua Led khong t 5mA n 20mA Led c s dng lm n bo ngun, n nhy trang tr, bo trng thi c in . vv

Diode pht quang LED 3.4 Diode Varicap ( Diode bin dung ) Diode bin dung l Diode c in dung nh t in, v in dung bin i khi ta thay i in p ngc t vo Diode.

n dng ca Diode bin dung Varicap ( VD ) trong mch cng hng

hnh trn khi ta chnh trit p VR, in p ngc t vo Diode Varicap thay i , in dung ca diode thay i => lm thay i tn s cng hng ca mch.

Diode bin dung c s dng trong cc b knh Ti vi mu, trong cc mch iu chnh tn s cng hng bng in p. 3.5 - Diode xung Trong cc b ngun xung th u ra ca bin p xung , ta phi dng Diode xung chnh lu. diode xung l diode lm vic tn s cao khong vi chc KHz , diode nn in thng thng khng th thay th vo v tr diode xung c, nhng ngc li diode xung c th thay th cho v tr diode thng, diode xung c gi thnh cao hn diode thng nhiu ln. V c im , hnh dng th Diode xung khng c g khc bit vi Diode thng, tuy nhin Diode xung thng c vng dnh du t nt hoc nh du bng hai vng

K hiu ca Diode xung 3.6 Diode tch sng. L loi Diode nh v bng thu tinh v cn gi l diode tip im v mt tip xc gia hai cht bn dn P N ti mt im trnh in dung k sinh, diode tch sng thng dng trong cc mch cao tn dng tch sng tn hiu. 3.7 Diode nn in. L Diode tip mt dng nn in trong cc b chnh lu ngun AC 50Hz , Diode ny thng c 3 loi l 1A, 2A v 5A.

Diode nn in 5A

1 Gii thiu v Transistor1.1 Cu to ca Transistor. ( Bng bn dn ) Transistor gm ba lp bn dn ghp vi nhau hnh thnh hai mi tip gip P-N , nu ghp theo th t PNP ta c Transistor thun , nu ghp theo th t NPN ta c Transistor ngc. v phng din cu to Transistor tng ng vi hai Diode u ngc chiu nhau .

Cu to Transistor

Ba lp bn dn c ni ra thnh ba cc , lp gia gi l cc gc k hiu l B ( Base ), lp bn dn B rt mng v c nng tp cht thp.

Hai lp bn dn bn ngoi c ni ra thnh cc pht ( Emitter ) vit tt l E, v cc thu hay cc gp ( Collector ) vit tt l C, vng bn dn E v C c cng loi bn dn (loi N hay P ) nhng c kch thc v nng tp cht khc nhau nn khng hon v cho nhau c. 1.2 - Nguyn tc hot ng ca Transistor. * Xt hot ng ca Transistor NPN .

Mch kho st v nguyn tc hot ng ca transistor NPN

Ta cp mt ngun mt chiu UCE vo hai cc C v E trong (+) ngun vo cc C v (-) ngun vo cc E.

Cp ngun mt chiu UBE i qua cng tc v tr hn dng vo hai cc B v E , trong cc (+) vo chn B, cc (-) vo chn E.

Khi cng tc m , ta thy rng, mc d hai cc C v E c cp in nhng vn khng c dng in chy qua mi C E ( lc ny dng IC = 0 )

Khi cng tc ng, mi P-N c phn cc thun do c mt dng in chy t (+) ngun UBE qua cng tc => qua R hn dng => qua mi BE v cc (-) to thnh dng IB

Ngay khi dng IB xut hin => lp tc cng c dng IC chy qua mi CE lm bng n pht sng, v dng IC mnh gp nhiu ln dng IB

Nh vy r rng dng IC hon ton ph thuc vo dng IB v ph thuc theo mt cng thc . IC = .IB

Trong IC l dng chy qua mi CE

IB l dng chy qua mi BE

l h s khuych i ca Transistor

Gii thch : Khi c in p UCE nhng cc in t v l trng khng th vt qua mi tip gip P-N to thnh dng in, khi xut hin dng IBE do lp bn dn P ti cc B rt mng v nng pha tp thp, v vy s in t t do t lp bn dn N ( cc E ) vt qua tip gip sang lp bn dn P( cc B ) ln hn s lng l trng rt nhiu, mt phn nh trong s cc in t th vo l trng to thnh dng IB cn phn ln s in t b ht v pha cc C di tc dng ca in p UCE => to thnh dng ICEchy qua Transistor. * Xt hot ng ca Transistor PNP . S hot ng ca Transistor PNP hon ton tng t Transistor NPN nhng cc tnh ca cc ngun in UCE v UBE ngc li . Dng IC i t E sang C cn dng IB i t E sang B.

2 K hiu v hnh dng ca Transistor2.1 - K hiu & hnh dng Transistor .

K hiu ca Transistor

Transistor cng xut nh 2.2 - K hiu ( trn thn Transistor ) *

Transistor cng xut ln

Hin nay trn th trng c nhiu loi Transistor ca nhiu nc sn xut nhng thng dng nht l cc transistor ca Nht bn, M v Trung quc.

Transistor Nht bn : thng k hiu l A, B, C, D

V d A564, B733, C828, D1555

trong cc Transistor k hiu l A v B l Transistor thun PNP cn k hiu l C v D l Transistor ngc NPN. cc

Transistor A v C thng c cng xut nh v tn s lm vic cao cn cc Transistor B v D thng c cng xut ln v tn s lm vic thp hn.

Transistor do M sn xut. thng k hiu l 2N Transistor do Trung quc sn xut :

v d 2N3055, 2N4073 vv

Bt u bng s 3, tip theo l hai ch ci. Ch ci thc nht cho bit loi bng : Ch A v B l bng thun , ch C v D l bng ngc, ch th hai cho bit c im : X v P l bng m tn, A v G l bng cao tn. Cc ch s sau ch th t sn phm. 3AP20 vv.. 2.3 - Cch xc nh chn E, B, C ca Transistor. Th d : 3CP25 ,

Vi cc loi Transistor cng xut nh th th t chn C v B tu theo bng ca nc no s xut , nhng chn E lun bn tri nu ta Transistor nh hnh di

Nu l Transistor do Nht sn xut : th d Transistor C828, A564 th chn C gia , chn B bn phi.

Nu l Transistor Trung quc sn xut th chn B gia , chn C bn phi.

Tuy nhin mt s Transistor c sn xut nhi th khng theo th t ny => bit chnh xc ta dng phng php o bng ng h vn nng.

Transistor cng xut nh.

Vi loi Transistor cng xut ln (nh hnh di ) th hu ht u c chung th t chn l : Bn tri l cc B, gia l cc C v bn phi l cc E.

Transistor cng xut ln thng c th t chn nh trn. * o xc nh chn B v C

Vi Transistor cng xut nh th thng thng chn E bn tri nh vy ta ch xc nh chn B v suy ra chn C l chn cn li.

ng h thang x1 , t c nh mt que o vo tng chn , que kia chuyn sang hai chn cn li, nu kim ln = nhau th chn c que t c nh l chn B, nu que ng h c nh l que

3- Phng php kim tra Transistor

en th l Transistor ngc, l que th l Transistor thun..

Transistor khi hot ng c th h hng do nhiu nguyn nhn, nh hng do nhit , m, do in p ngun tng cao hoc do cht lng ca bn thn Transistor, kim tra Transistor bn hy nh cu to ca chng.

Cu to ca Transistor

Kim tra Transistor ngc NPN tng t kim tra hai Diode u chung cc Ant, im chung l cc B, nu o t B sang C v B sang E ( que en vo B ) th tng ng nh o hai diode thun chiu => kim ln , tt c cc trng hp o khc kim khng ln.

Kim tra Transistor thun PNP tng t kim tra hai Diode u chung cc Katt, im chung l cc B ca Transistor, nu o t B sang C v B sang E ( que vo B ) th tng ng nh o hai diode thun chiu => kim ln , tt c cc trng hp o khc kim khng ln.

Tri vi cc iu trn l Transistor b hng. Transistor c th b hng cc trng hp .

*

o thun chiu t B sang E hoc t B sang C => kim

khng ln l transistor t BE hoc t BC * o t B sang E hoc t B sang C kim ln c hai chiu l chp hay d BE hoc BC. * o gia C v E kim ln l b chp CE. * Cc hnh nh minh ho khi o kim tra Transistor.

Php o cho bit Transistor cn tt .

Minh ho php o trn : Trc ht nhn vo k hiu ta bit c Transistor trn l bng ngc, v cc chn ca Transistor ln lt l ECB ( da vo tn Transistor ). < xem li phn xc nh chn Transistor >

Bc 1 : Chun b o ng h thang x1 Bc 2 v bc 3 : o thun chiu BE v BC => kim ln . Bc 4 v bc 5 : o ngc chiu BE v BC => kim khng ln. Bc 6 : o gia C v E kim khng ln => Bng tt. -

Php o cho bit Transistor b chp BE

Bc 1 : Chun b . Bc 2 : o thun gia B v E kim ln = 0 Bc 3: o ngc gia B v E kim ln = 0 => Bng chp BE

Php o cho bit bng b t BE

Bc 1 : Chun b . Bc 2 v 3 : o c hai chiu gia B v E kim khng ln. => Bng t BE

Php o cho thy bng b chp CE

Bc 1 : Chun b . Bc 2 v 4 : o c hai chiu gia C v E kim ln = 0 => Bng chp CE Trng hp o gia C v E kim ln mt cht l b d CE.

4 Cc thng s k thut ca Transistor4.1 Cc thng s k thut ca Transistor

Dng in cc i : L dng in gii hn ca transistor, vt qua dng gii hn ny Transistor s b hng. in p cc i : L in p gii hn ca transistor t vo cc CE , vt qua in p gii hn ny Transistor s b nh thng. Tn s ct : L tn s gii hn m Transistor lm vic bnh thng, vt qu tn s ny th khuych i ca Transistor b gim . H s khuych i : L t l bin i ca dng ICE ln gp bao nhiu ln dng IBE Cng xut cc i : Khi hoat ng Transistor tiu tn mt cng xut P = UCE . ICE nu cng xut ny vt qu cng xut cc i ca Transistor th Transistor s b hng . 4.2 - Mt s Transistor c bit . * Transistor s ( Digital Transistor ) : Transistor s c cu to nh Transistor thng nhng chn B c u thm mt in tr vi chc K

Transistor s thng c s dng trong cc mch cng tc , mch logic, mch iu khin , khi hot ng ngi ta c th a trc tip p lnh 5V vo chn B iu khin n ngt m.

Minh ho ng dng ca Transistor Digital * K hiu : Transistor Digital thng c cc k hiu l DTA( dn thun ), DTC( n ngc ) , KRC( n ngc ) KRA( n thun), RN12( n ngc ), RN22(n thun ), UN., KSR . Th d : DTA132 , DTC 124 vv * Transistor cng xut dng ( cng xut ngang ) Transistor cng xut ln thng c gi l s. S dng, S ngun vv..cc s ny c thit k iu khin b cao p hoc bin p ngun xung hot ng , Chng thng c in p hot ng cao v cho dng chu ng ln. Cc s cng xut dng( Ti vi mu) thng c u thm cc diode m trong song song vi cc CE.

5 Phn cc cho Transistor

S cng xut dng trong Ti vi mu

5.1 Cp in cho Transistor ( Vcc in p cung cp ) s dng Transistor trong mch ta cn phi cp cho n mt ngun in, tu theo mc ch s dng m ngun in c cp trc tip vo Transistor hay i qua in tr, cun dy v v ngun in Vcc cho Transistor c quy c l ngun cp cho cc CE.

Cp ngun Vcc cho Transistor ngc v thun

Ta thy rng : Nu Transistor l ngc NPN th Vcc phi l ngun dng (+), nu Transistor l thun PNP th Vcc l ngun m (-) 5.2 nh thin ( phn cc ) cho Transistor . * nh thin : l cp mt ngun in vo chn B ( qua tr nh thin) t Transistor vo trng thi sn sng hot ng, sn sng khuych i cc tn hiu cho d rt nh.

* Ti sao phi nh thin cho Transistor n mi sn sng hot ng ? : hiu c iu ny ta hy xt hai s trn :

trn l hai mch s dng transistor khuych i tn hiu, mt mch chn B khng c nh thin v mt mch chn B c nh thin thng qua Rt.

Cc ngun tn hiu a vo khuych i thng c bin rt nh ( t 0,05V n 0,5V ) khi a vo chn B( n cha c nh thin) cc tn hiu ny khng to ra dng IBE ( c im mi P-N pha c 0,6V mi c dng chy qua ) => v vy cng khng c dng ICE => st p trn Rg = 0V v in p ra chn C = Vcc

s th 2 , Transistor c Rt nh thin => c dng IBE, khi a tn hiu nh vo chn B => lm cho dng IBE tng hoc gim => dng ICEcng tng hoc gim , st p trn Rg cng thay i => v kt qu u ra ta thu c mt tn hiu tng t u vo nhng c bin ln hn. => Kt lun : nh thin ( hay phn cc) ngha l to mt dng in IBE ban u, mt st p trn Rg ban u khi c mt ngun tn hiu yu i vo cc B , dng IBE s tng hoc gim => dng ICE cng tng hoc gim => dn n st p trn Rg cng tng hoc gim => v st p ny chnh l tn hiu ta cn ly ra . 5.3 - Mt s mach nh thin khc . * Mch nh thin dng hai ngun in khc nhau .

Mch nh thin dng hai ngun in khc nhau * Mach nh thin c in tr phn p c th khuch i c nhiu ngun tn hiu mnh yu khc nhau, th mch nh thin thng s dng thm in tr phn p Rpa u t B xung Mass.

Mch nh thin c in tr phn p Rpa * Mch nh thin c hi tip . L mch c in tr nh thin u t u ra (cc C ) n u vo ( cc B) mch ny c tc dng tng n nh cho mch khuych i khi hot ng.