fet va bjt

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/


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.


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


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.


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


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





9 2SK1794 N-Channel 6A,100W







16 2SK2333 N-FET 6A,50W


7/23













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



36 IRF 510 N-Channel 5A,43W









45 IRF 710 N-Channel 2A,36W46 IRF 720 N-Channel 3A,50W







8/23




55 IRF 9610 P-Channel 2A,20W




59 IRFI 510G N-Channel 4A,27W














73 IRFI 9620G P-Channel 2A,30W



76 IRFS 520 N-Channel 7A,30W




80 IRFS 630 N-Channel 6A,35W81 IRFS 634 N-Channel 5A,35W





86 IRFS 820 N-Channel 2A-30W


9/23


10/23

121 MTP8N48 N-Channel 8A-125W




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/


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 .


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


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.


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.


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.


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.

-


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


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


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.


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 )


21/23


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.


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/

fet va bjt

Documents