Post on 02-Jun-2018
8/10/2019 FET va BJT
1/23
HocDienTu.co.cc & HocDieuKhien.co.cc
1. Gii thiu v Mosfet
Mosfet l Transistor hiu ng trng
( Metal Oxide Semiconductor Field Effect Transistor ) l mt Transistor
c bit c cu to v hot ng khc vi Transistor thng thng
m ta bit, Mosfet c nguyn tc hot ng da trn hiu ng t
trng to ra dng in, l linh kin c tr khng u vo ln thch
hn cho khuych i cc ngun tn hiu yu, Mosfet c s dng nhiu
trong cc mch ngun Monitor, ngun my tnh .
Transistor hiu ng trng Mosfet
2. Cu to v k hiu ca Mosfet.
http://hocdieukhien.wordpress.com/http://hocdieukhien.wordpress.com/http://hocdieukhien.wordpress.com/8/10/2019 FET va BJT
2/23
K hiu v s chn tng ng
gia Mosfet v Transistor
* Cu to ca Mosfet.
Cu to ca Mosfet ngc Knh N
G : Gate gi l cc cng
S : Source gi l cc ngun
D : Drain gi l cc mng
Mosfet kn N c hai ming bn dn loi P t trn nn bn dn N, gia hai lp P -N c cch in bi lp
SiO2
hai ming bn dn P c ni ra thnh cc D v cc S, nn bn dn N
c ni vi lp mng mng trn sau c du ra thnh cc G.
8/10/2019 FET va BJT
3/23
Mosfet c in tr gia cc G vi cc S v gia
cc G vi cc D l v cng ln , cn in tr gia cc D v cc S
ph thuc vo in p chnh lch gia cc G v cc S ( UGS)
Khi in p UGS= 0 th in tr RDSrt ln, khi in p UGS> 0 => do hiu ng t trng lm cho in
tr RDSgim, in p UGScng ln th in tr RDScng nh.
3. Nguyn tc hot ng ca Mosfet
Mch in th nghim.
Mch th nghim s hot ng ca Mosfet
Th nghim: Cp ngun mt chiu UD
qua mt bng n D vo hai cc D v S ca Mosfet Q (Phn cc thun cho
Mosfet ngc) ta thy bng n khng sng ngha l khng c dng in
i qua cc DS khi chn G khng c cp in.
Khi cng tc K1 ng, ngun UGcp vo hai cc GS lm in p UGS > 0V => n Q1 dn => bng n D
sng.
Khi cng tc K1 ngt, in p tch trn t C1 (t gm)
vn duy tr cho n Q dn => chng t khng c dng in i qua cc
GS.
Khi cng tc K2 ng, in p tch trn t C1 gim bng 0 => UGS= 0V => n tt
=> T thc nghim trn ta thy rng : in p t
vo chn G khng to ra dng GS nh trong Transistor thng thng m
in p ny ch to ra t trng => lm cho in tr RDSgim xung .
4. o kim tra Mosfet
Mt Mosfet cn tt: L khi o tr khng
gia Gvi S v gia G vi D c in tr bng v cng ( kim khng ln
8/10/2019 FET va BJT
4/23
c hai chiu o) v khi G c thot in th tr khng gia D
v S phi l v cng.
Cc bc kim tra nh sau :
o kim tra Mosfet ngc thy cn tt.
Bc 1 : Chun b thang x1K
Bc 2 : Np cho G mt in tch ( que en vo G que vo S hoc D )
Bc 3 : Sau khi np cho G mt in tch ta o gia D v S ( que en vo D que vo S ) => kim s
ln.
Bc 4 : Chp G vo D hoc G vo S thot in chn G.
Bc 5 : Sau khi thot in chn G o li DS nh bc 3 kim khng ln.
=> Kt qu nh vy l Mosfet tt.
8/10/2019 FET va BJT
5/23
o kim tra Mosfet ngc thy b chp
Bc 1 : ng h thang x 1K
o gia G v S hoc gia G v D nu kim ln = 0l chp
o gia D v S m c hai chiu o kim ln = 0l chp D S
5. ng dung ca Mosfet trong thc t
Mosfet trong ngun xung ca Monitor
Mosfet c s dng lm n cng xut ngun Monitor
8/10/2019 FET va BJT
6/23
Trong b ngun xung ca
Monitor hoc my vi tnh, ngi ta thng dng cp linh kin l IC to
dao ng v n Mosfet, dao ng to ra t IC c dng xung vung c
a n chn G ca Mosfet, ti thi im xung c in p > 0V =>
n Mosfet dn, khi xung dao ng = 0V Mosfet ngt => nh vy dao
ng to ra s iu khin cho Mosfet lin tc ng ngt tothnh dng
in bin thin lin tc chy qua cun s cp => sinh ra t trng
bin thin cm ng ln cc cun th cp => cho ta in p ra.
* o kim tra Mosfet trong mch .
Khi kim tra Mosfet trong mch , ta ch cn thang x1
v o gia D v S => Nu1 chiu kim ln o chiu o kim khng ln
=> l Mosfet bnh thng, Nu c hai chiu kim ln = 0l Mosfet b chp DS.
6. Bng tra cu Mosfet thng dng
Hng dn:
Loi knh dn: P-Channel: l Mosfet thun, N-Channell Mosfet ngc.
c im kthut :Th d: 3A, 25W : l dng D-S cc i v cng xut cc i.
STT K hiu Loi knh dn c im k thut
1 2SJ306 P-Channel 3A , 25W
2 2SJ307 P-Channel 6A, 30W
3 2SJ308 P-Channel 9A, 40W
4 2SK1038 N-Channel 5A, 50W
5 2SK1117 N-Channel 6A, 100W
6 2SK1118 N-Channel 6A, 45W
7 2SK1507 N-Channel 9A, 50W
8 2SK1531 N-Channel 15A, 150W
9 2SK1794 N-Channel 6A,100W
10 2SK2038 N-Channel 5A,125W
11 2SK2039 N-Channel 5A,150W
12 2SK2134 N-Channel 13A,70W
13 2SK2136 N-Channel 20A,75W
14 2SK2141 N-Channel 6A,35W
15 2SK2161 N-Channel 9A,25W
16 2SK2333 N-FET 6A,50W
8/10/2019 FET va BJT
7/23
17 2SK400 N-Channel 8A,100W
18 2SK525 N-Channel 10A,40W
19 2SK526 N-Channel 10A,40W
20 2SK527 N-Channel 10A,40W
21 2SK555 N-Channel 7A,60W
22 2SK556 N-Channel 12A,100W
23 2SK557 N-Channel 12A,100W
24 2SK727 N-Channel 5A,125W
25 2SK791 N-Channel 3A,100W
26 2SK792 N-Channel 3A,100W
27 2SK793 N-Channel 5A,150W
28 2SK794 N-Channel 5A,150W
29 BUZ90 N-Channel 5A,70W
30 BUZ90A N-Channel 4A,70W
31 BUZ91 N-Channel 8A,150W
32 BUZ 91A N-Channel 8A,150W
33 BUZ 92 N-Channel 3A,80W
34 BUZ 93 N-Channel 3A,80W
35 BUZ 94 N-Channel 8A,125W
36 IRF 510 N-Channel 5A,43W
37 IRF 520 N-Channel 9A,60W
38 IRF 530 N-Channel 14A,88W
39 IRF 540 N-Channel 28A,150W
40 IRF 610 N-Channel 3A,26W
41 IRF 620 N-Channel 5A,50W
42 IRF 630 N-Channel 9A,74W
43 IRF 634 N-Channel 8A,74W
44 IRF 640 N-Channel 18A,125W
45 IRF 710 N-Channel 2A,36W46 IRF 720 N-Channel 3A,50W
47 IRF 730 N-Channel 5A,74W
48 IRF 740 N-Channel 10A,125W
49 IRF 820 N-Channel 2A,50W
50 IRF 830 N-Channel 4A,74W
51 IRF 840 N-Channel 8A,125W
8/10/2019 FET va BJT
8/23
52 IRF 841 N-Channel 8A,125W
53 IRF 842 N-Channel 7A,125W
54 IRF 843 N-Channel 7A,125W
55 IRF 9610 P-Channel 2A,20W
56 IRF 9620 P-Channel 3A,40W
57 IRF 9630 P-Channel 6A,74W
58 IRF 9640 P-Channel 11A,125W
59 IRFI 510G N-Channel 4A,27W
60 IRFI 520G N-Channel 7A,37W
61 IRFI 530G N-Channel 10A,42W
62 IRFI 540G N-Channel 17A,48W
63 IRFI 620G N-Channel 4A,30W
64 IRFI 630G N-Channel 6A,35W
65 IRFI 634G N-Channel 6A,35W
66 IRFI 640G N-Channel 10A,40W
67 IRFI 720G N-Channel 3A,30W
68 IRFI 730G N-Channel 4A,35W
69 IRFI 740G N-Channel 5A,40W
70 IRFI 820G N-Channel 2A,30W
71 IRFI 830G N-Channel 3A,35W
72 IRFI 840G N-Channel 4A,40W
73 IRFI 9620G P-Channel 2A,30W
74 IRFI 9630G P-Channel 4A,30W
75 IRFI 9640G P-Channel 6A,40W
76 IRFS 520 N-Channel 7A,30W
77 IRFS 530 N-Channel 9A,35W
78 IRFS 540 N-Channel 15A,40W
79 IRFS 620 N-Channel 4A,30W
80 IRFS 630 N-Channel 6A,35W81 IRFS 634 N-Channel 5A,35W
82 IRFS 640 N-Channel 10A,40W
83 IRFS 720 N-Channel 2A,30W
84 IRFS 730 N-Channel 3A,35W
85 IRFS 740 N-Channel 3A,40W
86 IRFS 820 N-Channel 2A-30W
8/10/2019 FET va BJT
9/23
8/10/2019 FET va BJT
10/23
121 MTP8N48 N-Channel 8A-125W
122 MTP8N49 N-Channel 8A-125W
123 MTP8N50 N-Channel 8A-125W
124 MTP8N80 N-Channel 8A-75W
Ngun:hocnghe.com.vn
li phn hi
Thng Su 24, 2009
C bn: Transistor
Filed under:C bnMrZen @ 2:20 sng
Tags:ban dan,co ban,linh kien ban dan
C bn: Transistor
1 Gii thiu v Transistor
1.1 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.
http://hocnghe.com.vn/http://hocnghe.com.vn/http://hocnghe.com.vn/http://hocdieukhien.wordpress.com/2009/06/25/c%c6%a1-b%e1%ba%a3n-mosfet-transistor-tr%c6%b0%e1%bb%9dng/#respondhttp://hocdieukhien.wordpress.com/2009/06/25/c%c6%a1-b%e1%ba%a3n-mosfet-transistor-tr%c6%b0%e1%bb%9dng/#respondhttp://hocdieukhien.wordpress.com/2009/06/24/c%c6%a1-b%e1%ba%a3n-transistor/http://hocdieukhien.wordpress.com/2009/06/24/c%c6%a1-b%e1%ba%a3n-transistor/http://hocdieukhien.wordpress.com/category/c%c6%a1-b%e1%ba%a3n/http://hocdieukhien.wordpress.com/category/c%c6%a1-b%e1%ba%a3n/http://hocdieukhien.wordpress.com/category/c%c6%a1-b%e1%ba%a3n/http://hocdieukhien.wordpress.com/tag/ban-dan/http://hocdieukhien.wordpress.com/tag/ban-dan/http://hocdieukhien.wordpress.com/tag/ban-dan/http://hocdieukhien.wordpress.com/tag/co-ban/http://hocdieukhien.wordpress.com/tag/co-ban/http://hocdieukhien.wordpress.com/tag/co-ban/http://hocdieukhien.wordpress.com/tag/linh-kien-ban-dan/http://hocdieukhien.wordpress.com/tag/linh-kien-ban-dan/http://hocdieukhien.wordpress.com/tag/linh-kien-ban-dan/http://hocdieukhien.wordpress.com/tag/linh-kien-ban-dan/http://hocdieukhien.wordpress.com/tag/co-ban/http://hocdieukhien.wordpress.com/tag/ban-dan/http://hocdieukhien.wordpress.com/category/c%c6%a1-b%e1%ba%a3n/http://hocdieukhien.wordpress.com/2009/06/24/c%c6%a1-b%e1%ba%a3n-transistor/http://hocdieukhien.wordpress.com/2009/06/25/c%c6%a1-b%e1%ba%a3n-mosfet-transistor-tr%c6%b0%e1%bb%9dng/#respondhttp://hocnghe.com.vn/8/10/2019 FET va BJT
11/23
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 UCEvo hai cc C v E trong (+) ngun vo cc C v (-) ngun vo cc E.
Cp ngun mt chiu UBEi 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 ICchy qua mi CE lm bng npht sng, v dng
IC mnh gp nhiu ln dng IB
Nh vy r rng dng IChon ton ph thuc vo dng IBv ph thuc theo mt cng thc .
8/10/2019 FET va BJT
12/23
IC= .IB
Trong ICl 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 UCEnhng 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 IBcn 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 ICi t E sang C cn dng IBi t E sang B.
2 K hiu v hnh dng ca Transistor
2.1 K hiu & hnh dng Transistor .
K hiu ca Transistor
Transistor cng xut nh Transistor cng xut ln
8/10/2019 FET va BJT
13/23
2.2 K hiu ( trn thn Transistor )
*
Hin nay trn th trng c nhiu loi Transistor ca nhiu nc sn
xutnhng 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 dA564, 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 d2N3055, 2N4073vv
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..
2.3 Cch xc nh chn E, B, C ca Transistor.
Vi cc loi Transistor cng xut nhth 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.
8/10/2019 FET va BJT
14/23
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..
3- Phng php kim tra Transistor
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.
8/10/2019 FET va BJT
15/23
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.
8/10/2019 FET va BJT
16/23
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.
-
8/10/2019 FET va BJT
17/23
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
8/10/2019 FET va BJT
18/23
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
8/10/2019 FET va BJT
19/23
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 Transistor
4.1 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 ICEln 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 thmmt in tr vi chc K
Transistor s thng c s
dng trongcc 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.
8/10/2019 FET va BJT
20/23
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.
S cng xut dng trong Ti vi mu
5 Phn cc cho Transistor
5.1 Cp in cho Transistor ( Vcc in p cung cp )
8/10/2019 FET va BJT
21/23
8/10/2019 FET va BJT
22/23
* 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
chyqua ) => 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 , stp 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 IBEban u, mt st p trn Rg ban u khi c
mt ngun tn hiu yui vo cc B , dng IBEs tng hoc gim => dng ICEcng 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.
8/10/2019 FET va BJT
23/23
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.
Ngun:hocnghetructuyen.vn
li phn hi
http://hocnghe.com.vn/http://hocnghe.com.vn/http://hocnghe.com.vn/http://hocdieukhien.wordpress.com/2009/06/24/c%c6%a1-b%e1%ba%a3n-transistor/#respondhttp://hocdieukhien.wordpress.com/2009/06/24/c%c6%a1-b%e1%ba%a3n-transistor/#respondhttp://hocdieukhien.wordpress.com/2009/06/24/c%c6%a1-b%e1%ba%a3n-transistor/#respondhttp://hocnghe.com.vn/