Cu to ca Transitor Transitor hay cn gi l bng dn 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 trc ny c gi l Bipolar Junction Transitor (BJT) v dng in chy trong cu trc ny bao gm c hai loi in tch m v dng (Bipolar ngha l hai cc tnh)

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 K hiu Hnh dng Xc nh chn K hiu & hnh dng Transistor . Transitor c k hiu trong cc s mch.

Ngoi thc t th transior c k hiu sau:

y ch l mt s hnh dng quen thuc. C nhiu loi Transitor c k hiu khc th ny . K hiu ( trn thn Transistor ) * 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 v d 2N3055, 2N4073 vv Transistor do Trung quc sn xut : 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. Th d : 3CP25 , 3AP20 vv.. Trn y ch l ni chung cc Transitor c mt VN cn nhiu hng khc sn xut vi nhng k hiu khc. Cch xc nh chn E, B, C ca Transistor. 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 en th l Transistor ngc, l que th l Transistor thun.. Nguyn tc hot ng ca Transitor Trong ch tuyn tnh hay cn gi l ch khuych i, Transitor l phn t khuych i dng in vi dng Ic bng ln dng bazo (dng iu khin ) Trong l h s khuych i dng in . Ic = IB Xt c tnh ng ct: Ca PNP Ch ng ct ca Transitor ph thuc ch yu vo cc t k sinh gia tip gip BE v BC.

+ : Qu trnh m: cho transitor m c th bt u t gi tr -Ub2 n Ub1 cn n th no cc bn xem nhng cun gio trnh v in t + Qu trnh ng : cho transitor ng th bt u t gi tr t Ub1 n -Ub2. Ci ny cc bn cng tham kho thm sch. * S mc Darlington Ni chng cc BJT c h s khuych i tng i thp m yu cu dng iu khin ln nn s mc Darlington l mt yu cu t ra vi cc ghp 2 transitor Q1 v Q2 c h s khuych i l 1 2. Khi mc thnh Darling ton th h s khuych i tng l: = 1 + 2 + 12 Mt khc tng h s khuych i ln ta c th mc t 3 transotor S mc Darlington:

Xt nguyn l hot ng ca PNP

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 PN 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 ICE chy qua Transistor. 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. Ch : Transitor l linh kin ng m bng dng in ch khng bng in p. Kim tra Transitor 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 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. * : Cch kim tra Transitor thng dng (Dng loi PNP) : Khi cc transitor ta a bit cc chn ca n ( trn) Vic kim tra n c sng hay cht chng ta lm theo sau y : + : Php o cho bit Transistor cn tt . ( ng h kim o thang 1K hay ng h in t th thang o diode) que vo chn B v cho ln lt que en vo hai chn cn li l C v E Nu o BC v BE m kim cng ln th ==> Transitor ny cn dng c

+ : Php o bng chp BE Cng chun b que o nh ln trc . xc nh c n c chp BE hay khng th ta ch cn o gia B v E kim bng 0 m l ok. Ta ch cn cho que vo B , en vo E v ngc li nu kim bng 0 m ==> chp BE = > Cng khng dng c + : Php o bng t BE Cng tng t nh pc chp BE thi nhng m ci ny l kim n khng ln u! + : Chp CE : Cng chun b php o nh ln trc (1k) o qua li gia C v E nu kim ch s 0 th chp CE => khng dng c phi mua con mi! Qua trn ti gii thiu vi cc bn cch o Transitor sng hay l cht. Ch : ng h s dng trn l ng h kim ch khng phi ng h s. Cc thng s k thut Mt s loi transitor c bit 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 . Mt s Transistor c bit

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.

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. ng dng ca Transitor Thc ra mt thit b khng c Transistor th cha phi l thit b in t, v vy Transistor c th xem l mt linh kin quan trng nht trong cc thit b in t, cc loi IC thc cht l cc mch tch hp nhiu Transistor trong mt linh kin duy nht, trong mch in , Transistor c dng khuych i tn hiu Analog, chuyn trng thi ca mch Digital, s dng lm cc cng tc in t, lm cc b to dao ng v v Ni chung y c c mch no ni n in t l c Transitor . ng dng ca BJT n c ng dng rng ri trong tt c cc thit b in t

*Nguyn tc hot ng ca Transitor:

i vi NPN ta xt hot ng ca N theo hnh v sau

Ta cp ngun mt chiu U CE vo hai cc C v E trong cc C ni vi (+) cn cc E ni (-) nh hnh v. Ta cp ngun U BE i qua cng tc v hn tr dng vo hai cc B v E trong (+) vo chn B cn (-) vo chn E . Khi ta m cng tc ta thy rng khi hai cc C v E c dng in nhng n li khng sng lc ny dng qua C =0 Khi cng tc ng mi P_N c phn cc thun do c dng in chy t (+) ngun U qua BE

cng tc ri qua mi BE v cc m to thnh dng baz .Khi dng baz xut hin th ngay lp tc cng c dng C lm cho bng n sng v dng C mnh hn gp nhiu ln dng B. Do dng C ph thuc hon ton vo dng B c tnh theo cng thc : Ic =Ib Ic l dng chy qua CE Ib Lf dng chy qua BE l h s khuych i Cn i vi Transitor PNP l Thun th ta lm ngc li v phi i li cc tnh Qua ta thy : Transitor nh l mt kho in t trong B l cc iu khin . Dng EC ph thuc hon ton vo in p a vo B.

1. Khi nim v in tr. in tr l g ? Ta hiu mt cch n gin in tr l s cn tr dng in ca mt vt dn in, nu mt vt dn in tt th in tr nh, vt dn in km th in tr ln, vt cch in th in tr l v cng ln. in tr ca dy dn : in tr ca dy dn ph thc vo cht liu, di v tit din ca dy. c tnh theo cng thc sau: R = .L / S

Trong l in tr xut ph thuc vo cht liu L l chiu di dy dn S l tit din dy dn R l in tr n v l Ohm

2. in tr trong thit b in t.

a) Hnh dng v k hiu : Trong thit b in t in tr l mt linh kin quan trng, chng c lm t hp cht cacbon v kim loi tu theo t l pha trn m ngi ta to ra c cc loi in tr c tr s khc nhau.

Hnh dng ca in tr trong thit b in t.

K hiu ca in tr trn cc s nguyn l. b) n v ca in tr

n v in tr l (Ohm) , K , M 1K = 1000 1M = 1000 K = 1000.000

b) Cch ghi tr s ca in tr

Cc in tr c kch thc nh c ghi tr s bng cc vch mu theo mt quy c chung ca th gii.( xem hnh trn ) Cc in tr c kch thc ln hn t 2W tr ln thng c ghi tr s trc tip trn thn. V d nh cc in tr cng xut, in tr s.

Tr s cng xut ln , tr s c ghi trc tip. 3. Cch c tr s in tr . Quy c mu Quc t Mu sc Gi tr en 0 Mu sc Gi tr Xanh l 5

Nu Cam Vng

1 2 3 4

Xanh l Tm Xm Trng Nh vng Nh bc

6 7 8 9 -1 -2

in tr thng c k hiu bng 4 vng mu , in tr chnh xc th k hiu bng 5 vng mu. * Cch c tr s in tr 4 vng mu :

Cch c in tr 4 vng mu

Vng s 4 l vng cui lun lun c mu nh vng hay nh bc, y l vng ch sai s ca in tr, khi c tr s ta b qua vng ny. i din vi vng cui l vng s 1, tip theo n vng s 2, s 3 Vng s 1 v vng s 2 l hng chc v hng n v Vng s 3 l bi s ca c s 10. Tr s = (vng 1)(vng 2) x 10 ( m vng 3) C th tnh vng s 3 l s con s khng 0 thm vo Mu nh ch c vng sai s hoc vng s 3, nu vng s 3 l nh th s m ca c s 10 l s m.

* Cch c tr s in tr 5 vng mu : ( in tr chnh xc )

Vng s 5 l vng cui cng , l vng ghi sai s, tr 5 vng mu th mu sai s c nhiu mu, do gy kh khn cho ta khi xc inh u l vng cui cng, tuy nhin vng cui lun c khong cch xa hn mt cht. i din vng cui l vng s 1 Tng t cch c tr s ca tr 4 vng mu nhng y vng s 4 l bi s ca c s 10, vng s 1, s 2, s 3 ln lt l hng trm, hng chc v hng n v.

Tr s = (vng 1)(vng 2)(vng 3) x 10 ( m vng 4) C th tnh vng s 4 l s con s khng 0 thm vo

4 Thc hnh c tr s in tr.

Cc in tr khc nhau vng mu th 3

Khi cc in tr khc nhau vng mu th 3, th ta thy vng mu bi s ny thng thay i t mu nh bc cho n mu xanh l , tng ng vi in tr < 1 n hng M.

Cc in tr c vng mu s 1 v s 2 thay i .

hnh trn l cc gi tr in tr ta thng gp trong thc t, khi vng mu s 3 thay i th cc gi tr in tr trn tng gim 10 ln.

Bi tp - Bn hy on nhanh tr s trc khi p n xut hin, khi no tt c cc tr s m bn on ng trc khi kt qu xut hin l kin thc ca bn phn ny n ri !

Bi tp on nhanh kt qu tr s in tr. 5 Cc tr s in tr thng dng. Ta khng th kim c mt in tr c tr s bt k, cc nh sn xut ch a ra khong 150 loi tr s in tr thng dng , bng di y l mu sc v tr s ca cc in tr thng dng.

Cc gi tr in tr thng dng. 6 -. Phn loi in tr.

in tr thng : in tr thng l cc in tr c cng xut nh t 0,125W n 0,5W in tr cng xut : L cc in tr c cng xut ln hn t 1W, 2W, 5W, 10W. in tr s, in tr nhit : L cch gi khc ca cc in tr cng xut , in tr ny c v bc s, khi hot ng chng to nhit.

Cc in tr : 2W 1W 0,5W 0,25W

in tr s hay tr nhit 7 Cng xut ca in tr. Khi mc in tr vo mt on mch, bn thn in tr tiu th mt cng xut P tnh c theo cng thc P = U . I = U2 / R = I2.R

Theo cng thc trn ta thy, cng xut tiu th ca in tr ph thuc vo dng in i qua in tr hoc ph thuc vo in p trn hai u in tr. Cng xut tiu th ca in tr l hon ton tnh c trc khi lp in tr vo mch. Nu em mt in tr c cng xut danh nh nh hn cng xut n s tiu th th in tr s b chy. Thng thng ngi ta lp in tr vo mch c cng xut danh nh > = 2 ln cng xut m n s tiu th.

in tr chy do qu cng xut

s trn cho ta thy : Ngun Vcc l 12V, cc in tr u c tr s l 120 nhng c cng xut khc nhau, khi cc cng tc K1 v K2 ng, cc in tr u tiu th mt cng xut l

P = U2 / R = (12 x 12) / 120 = 1,2W

Khi K1 ng, do in tr c cng xut ln hn cng xut tiu th , nn in tr khng chy. Khi K2 ng, in tr c cng xut nh hn cng xut tiu th , nn in tr b chy .

8 Bin tr, trit p : Bin tr L in tr c th chnh thay i gi tr, c k hiu l VR chng c hnh dng nh sau :

Hnh dng bin tr K hiu trn s Bin tr thng rp trong my phc v cho qu trnh sa cha, cn chnh ca k thut vin, bin tr c cu to nh hnh bn di.

Cu to ca bin tr Trit p : Trit p cng tng t bin tr nhng c thm cn chnh v thng b tr pha trc mt my cho ngi s dng iu chnh. V d nh Trit p Volume, trit p Bass, Treec v.v.. , trit p ngha l trit ra mt phn in p t u vo tu theo mc chnh.

K hiu trit p trn s nguyn l.

Hnh dng trit p Cu to trong trit p 9 in tr mc ni tip .

in tr mc ni tip.

Cc in tr mc ni tip c gi tr tng ng bng tng cc in tr thnh phn cng li. Rtd = R1 + R2 + R3 Dng in chy qua cc in tr mc ni tip c gi tr bng nhau v bng I I = ( U1 / R1) = ( U2 / R2) = ( U3 / R3 )

T cng thc trn ta thy rng , st p trn cc in tr mc ni tip t l thun vi gi tr int tr .

10 in tr mc song song.

in tr mc song song

Cc in tr mc song song c gi tr tng ng Rtd c tnh bi cng thc (1 / Rtd) = (1 / R1) + (1 / R2) + (1 / R3) Nu mch ch c 2 in tr song song th Rtd = R1.R2 / ( R1 + R2) Dng in chy qua cc in tr mc song song t l nghch vi gi tr in tr . I1 = ( U / R1) , I2 = ( U / R2) , I3 =( U / R3 ) in p trn cc in tr mc song song lun bng nhau

11 in tr mc hn hp

in tr mc hn hp.

Mc hn hp cc in tr to ra in tr ti u hn . V d: nu ta cn mt in tr 9K ta c th mc 2 in tr 15K song song sau mc ni tip vi in tr 1,5K .

12 ng dng ca in tr in tr c mt mi ni trong thit b in t v nh vy in tr l linh kin quan trng khng th thiu c , trong mch in , in tr c nhng tc dng sau :

Khng ch dng in qua ti cho ph hp, V d c mt bng n 9V, nhng ta ch c ngun 12V, ta c th u ni tip bng n vi in tr st p bt 3V trn in tr.

u ni tip vi bng n mt in tr. - Nh hnh trn ta c th tnh c tr s v cng xut ca in tr cho ph hp nh sau: Bng n c in p 9V v cng xut 2W vy dng tiu th l I = P / U = (2 / 9 ) = Ampe cng chnh l dng in i qua in tr. - V ngun l 12V, bng n 9V nn cn st p trn R l 3V vy ta suy ra in tr cn tm l R = U/ I = 3 / (2/9) = 27 / 2 = 13,5 - Cng xut tiu th trn in tr l : P = U.I = 3.(2/9) = 6/9 W v vy ta phi dng in tr c cng xut P > 6/9 W

Mc in tr thnh cu phn p c c mt in p theo mun t mt in p cho trc.

Cu phn p ly ra p U1 tu . T ngun 12V trn thng qua cu phn p R1 v R2 ta ly ra in p U1, p U1 ph thuc vo gi tr hai in tr R1 v R2.theo cng thc . U1 / U = R1 / (R1 + R2) => U1 = U.R1/(R1 + R2) Thay i gi tr R1 hoc R2 ta s thu c in p U1 theo mun.

Phn cc cho bng bn dn hot ng .

Mch phn cc cho Transistor

Tham gia vo cc mch to dao ng R C

Mch to dao ng s dng IC 555