Bài Tập Mô Phỏng Nhóm 4

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I HC QUC GIA TP.HCM

TRNG I HC BCH KHOA

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BO CO M PHNG

Mn : MCH IN T 1

Gio vin hng dn : Thy: CH VIT NHT ANH

Sinh vin thc hin: L Thnh Huy 51101343

Li Ngc Tun 51104466

Lu Xun Hi 51104449

Nguyn Sang Trng Sn 51102938

TP.HCM, THNG 8 NM 2014

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I. Phn mm dng m phng: Phn mm c s dng l Proteus 8, l phn mm cho php m phng hot dng ca mch in t bao gm phn thit k mch v vit chuong trnh iu khin cho cc h vi iu khin nh MCS-51, PIC, AVR, Proteus l phn mm m phng mch in t ca Lancenter Electronics, m phng cho hu ht cc linh kin in t thng dngngoi ra cn m phng cc mch s, mch tuong t mt cch hiu qu. Proteus l b cng c chuyn v m phng mch in t.

*Hng dn s dng c bn Proteus : Bc 1: Khi ng chng trnh ISIS bng cch chn START -> All Program -> Proteus 7 Professional -> ISIS 7 Professional t mn hnh desktop ca Window

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Mn hnh lm vic ca ISIS xut hin vi y cc menu lnh cng nh cc

thanh cng c h tr cho vic to v m phng mch in.

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Bc 2: Ly linh kin t thanh cng c nhp chn vo Component Mode chn tip Pick

from Libraries ca s Pick Devices hin ra

Mun ly linh kin g, ch cn g tn linh kin , sau kch p vo linh kin ly linh

kin ra, v d nh cn ly in tr, ta g Res, sau kich p ly.

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Sau khi kch p vo linh kin trong th vin, ta ng ca s Pick Devices, trong khung

device selector s xut hin linh kin, chng ta nhp chn linh kin v a ra vng v nhp

chut tri l v xong linh kin.

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Sau khi v mch xong, chng ta c th cho mch chy bng cch kch vo nt Play bn gc

tri pha di nh trong hnh

II. Mc tiu: M phng c hot ng ca BJT v MOSFET, kho st mch v so vi l thuyt c hc. Lm quen vi vic ng dng l thuyt vo thc t.

III. M phng mch khuch i:

A. Mch khuch i BJT:

1. B chung (Common Base):

a) Gii thiu:

Mch khuch i BJT mc theo kiu B chung c chn B

u vo mass. Tn hiu c a vo cc E v ly ra trn cc

C.

ng dng ca B-common Amplifier Mch ny t khi c s dng trong cc mch c tn hiu tn s thp nh l b khuch i dng cho microphone. Mt khc, mch ny li c s dng rng ri trong cc mch

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tn s cao nh VHF (Very High Frequency 30 to 300MHz) v UHF (Ultra High Frequency 300MHz to 3GHz). Chng c s dng bi v t din khng b nh hung bi hiu ng Miller v c s cch ly cao gia tn hiu u vo v u ra v B (base) tch chng ra. V s cch ly cao nn dn dn b nh hung nh bi hin tng hi tip t output tr v input

n nh cao. b) M phng: S mch khuch i BJT mc B chung: = 240, VBE=0.7V

Phn cc DC:

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Kt qu m phng: IB=19.2 A

VC=6.26 V

VE=1.06 V

Kt qu tnh theo l thuyt:

VTH =

VCC =

12 = 1.83V

RTH =

= 3.05 k

VTH = RTHIB + VBE + (+1)REIB

IB=20 A VC = VCC RCIB = 12-240*1.2*20*10

-3 = 6.24V

VE = (+1)IBRE = 1.06V

Ch AC:

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Kt qu m phng: vo = 2.9V

vi = 3.52V

= 0.82


=

= 30.44

Sng ca Vin v Vout, mu vo l sng ca Vin, mu tm l sng Vout.

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c) Kt lun:

Kt qu tnh ton cc gi tr DC l thuyt gn st vi cc gi tr khi m phng. H s khuch i A l thuyt c s chnh lch ln vi thc t, 0.82 so vi 0.1 Sai s c th do:

Sai s ca cc thng s linh kin.

Cc thng s ca BJT BC547 trn thc t c th sai khc vi cc thng s l thuyt c lm trn.

2. C chung (common collector): a) Gii thiu:

Mch mc theo kiu C chung c chn C u vo mass hoc dng ngun. Tn hiu c a vo cc B v ly ra trn cc E, mch c s nh sau :

ng dng ca mch C chung: Mch c ng dng nhiu trong cc mch khuych i m (Damper), truc khi chia tn hiu lm nhiu nhnh, ngui ta thung dng mch Damper khuych i cho tn hiu kho hn. Ngoi ra mch cn c dng rt nhiu trong cc mch n p ngun.

b) M phng: S mch khuch i BJT mc C chung:

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Phn cc DC:

Kt qu m phng:

IB=17.4 A

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VC=12 V

VE=1.06 V


VTH =

VCC =

12 = 1.83V

RTH =

= 3.05 k


IB=20 A VC = 12V

VE = (+1)IBRE = 1.06V Ch AC:

Kt qu m phng: vo = 2 V

vi = 3.53V

= 0.57


=

= 0.97


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c) Kt lun: Kt qu tnh ton cc gi tr DC l thuyt gn st vi cc gi tr khi m phng. H s khuch i A l thuyt c s chnh lch ln vi thc t, 0.57 so vi 0.97 Sai s c th do:

ca cc thng s linh kin. ca BJT BC547 trn thc t c th sai khc vi cc thng s

l thuyt c lm trn. 3. E chung c RE:

a) Gii thiu: Mch khuych i BJT mc theo kiu E chung c cc E u trc tip xung

mass hoc u qua t xung mass thot thnh phn xoay chiu, tn hiu

a vo cc B v ly ra trn cc C.

Mch khuych i E chung c s nh sau :

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Mch mc theo kiu E chung nh trn c ng dng nhiu nht trong thit b in t.

b) M phng: S mch khuch i BJT mc E chung:

Phn cc DC:

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Kt qu m phng:

IB=19.2 A

VC=6.26 V

VE=1.06 V


VTH =

VCC =

12 = 1.83V

RTH =

= 3.05 k


IB=20 A VC = VCC RCIB = 12-240*1.2*20*10

-3 = 6.24V

VE = (+1)IBRE = 1.06V Ch AC:

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Kt qu m phng:

vo = 4.54 V

vi = 3.52V

= 1.29


=

= -2.41


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d) Kt lun: Kt qu tnh ton cc gi tr DC l thuyt gn st vi cc gi tr khi m phng

4. E chung khng c RE: a) Gii thiu:

Mch khuych i BJT mc theo kiu E chung c cc E u trc tip xung

mass hoc u qua t xung mass thot thnh phn xoay chiu, tn hiu

a vo cc B v ly ra trn cc C.

Mch khuych i E chung c s nh sau :

Mch mc theo kiu E chung nh trn c ng dng nhiu nht trong thit b in t.

b) M phng:

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Phn cc DC:

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Kt qu m phng:

IB=0.35 mA

VC=0.36 V

VE=0 V


VTH =

VCC =

12 = 1.83V

RTH =

= 3.05 k

VTH = RTHIB + VBE

IB=0.37 mA

VC = VCC RCIB = 12-240*1.2*0.37

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c) Kt lun:

Kt qu VC trong m phng sai so vi l thuyt. iu ny c th do phn mm.

B. Mch khuch i MOSFET: 1. G chung :

a) M phng: S mch khuch i MOSFET mc G chung:

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S dng MOSFET IRF540 c kn=2.75 A/V2 v Vt=2 V

Phn cc DC:

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Kt qu m phng:

ID = 1 mA

VGS = 2.06 V

gm =

= 67 mA/V


VTH =

VCC =

15 = 2.29 V

RTH =

= 3.05 k

IB=0 VG=VTH=2.29 V

ID=

kn(VGS-Vt)

2

ID=1.2mA

VGS=VG VS = 2.29-1.2*0.22=2.03V Ch AC:

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Kt qu m phng:

vo = 5.32 V

vi = 3.53V

= 1.5


= gm(RD//RL) = 1.2


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b) Kt lun:

Cc thng s thu c trn mch m phng ch c kt qu gn dng so vi l thuyt. c xy ra sai s c th do: - Cc sai s ca linh kin in t. - Do cc thng s ca JFET c mc nh trong m phng l c nh, cn trn thc t JFET c tra cc thng s cc diu kin khc nhau (datasheet).

- Do b qua in tr trong qu trnh tnh ton trn l thuyt (i vi tnh v ).

2. D chung: a) M phng:

S mch khuch i MOSFET mc D chung:

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Phn cc DC:

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Kt qu m phng:

ID = 1 mA

VGS = 2.06 V

gm =

= 67 mA/V


VTH =

VCC =

15 = 2.29 V

RTH =

= 3.05 k

IB=0 VG=VTH=2.29 V

ID=

kn(VGS-Vt)

2

ID=1.2mA

VGS=VG VS = 2.29-1.2*0.22=2.03V Ch AC:

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Kt qu m phng: vo = 0.97 V

vi = 3.53V

= 0.28


=

= 0,99


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b) Kt lun:



3. S chung c RS: a) M phng:

S mch khuch i MOSFET mc S chung:

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Phn cc DC:

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Kt qu m phng:

ID = 1 mA

VGS = 2.06 V

gm =

= 67 mA/V


VTH =

VCC =

15 = 2.29 V

RTH =

= 3.05 k

IB=0 VG=VTH=2.29 V

ID=

kn(VGS-Vt)

2

ID=1.2mA

VGS=VG VS = 2.29-1.2*0.22=2.03V Ch AC:

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vi = 3.53V

= 1.65


=

= -2.32


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b) Kt lun: Cc thng s thu c trn mch m phng ch c kt qu gn dng so vi l thuyt. c xy ra sai s c th do: - Cc sai s ca linh kin in t. - Do cc thng s ca JFET c mc nh trong m phng l c nh, cn trn thc t JFET c tra cc thng s cc diu kin khc nhau (datasheet).


4. S chung khng c RS: a) M phng:

S mch khuch i MOSFET mc S chung:

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Phn cc DC:

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Kt qu m phng:

ID = 12.4 mA

VGS = 2.29 V

gm =

= 67 mA/V


VTH =

VCC =

15 = 2.29 V

RTH =

= 3.05 k

IB=0 VG=VTH=2.29 V

ID=

kn(VGS-Vt)

2

ID=12mA

VGS=VG VS = 2.29-1.2*0.22=2.03V Ch AC:

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vi = 3.53V

= 1.56


= = -36.5

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b) Kt lun:



*Tng kt : Qua qu trnh tnh ton l thuyt v m phng thc t bng phn mm proteus 8.0, chng em nhn ra l thuyt v thc t khc xa nhau. Nhm lm vic tp trung nhng vn cha tm ra c nguyn nhn sai st khi thc hin m phng.

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Bài Tập Mô Phỏng Nhóm 4