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AeronauticaComunicatiiElectronica electricitateMerceologieTehnica mecanica


Circuitul nestabilizat, Circuitul stabilizat

Electronica electricitate

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Circuitul nestabilizat:




Figura1

Circuitul stabilizat:

Figura 2

Pentru circuitele stabilizatoare folosim modelele :

Ri=10M  ; Au=13% ; Ro<100 ; fj£10Hz ; fi³1MHz ;

Figura3

Am ales pentru tranzistorul Tec-J modelul 2N3819:

Vp=−3V ; Vpmax=−8V

IDSSmin=2mA ; IDSSmax=20mA

iD=0.8IDSS=1.8mA.

Pentru tranzistoarele Q2 si Q3 modelul 2N2222

b

uBE0=0.6V

Am ales pentru dioda zener modelul BZX55-B5V6:

uz=5.6V

Iz=5V ;

iD=iC3=1.8mA constant

iD=IDSS(1-uGS/Vp)2 Þ uGS=Vp(1∓√iD/IDSS) Þ

uGSmin=-0.15V

uGSmax=-5.6V ;

uDS≥∣uGS-Vpmax Þ uDS³7.85V

Vas+³uoM-VPmax ³11V

½Vas-½³uoM+uZoM+uCE3m+uGSm=10.45V

Vas+= ½Vas-½=12V

iD=1.8mA

uDS= Vas++ uGSmin=11.85V

ÞPSFJ1(1.8mA ;11.85V)

Calculam rezistentele

R1=10MW

RL=1kW

U(R3)=uZ , iD=iC3=iR3

R3=uz01/iR3=3.11kW → 3.3kW 5% - rezist. standardizata

u R2)= ½Vas-½-uD01-uZ=5.8V

R2= u R2)/iZ=1.16 kW → 1.3 kW

iC2 R4║RL=uoM

iC2 R4=½Vas-½-uBE2-uGsmin Þ R4=2.75 kW → 2.7 kW 5% , iC2=4.2mA;

uCE3=- uGSmin-uZ- Vas-=6.55V

PSF Q3(1.8mA ;6.55V)

uCE2=uDS+uBE2=12.45V

PSF Q2 (4.2mA ;12.45V) ;

Calculam puterile maxime disipate pe rezistente

Pd(R2)=R2iZ2=29mW→ 50mW

Pd(R3)= R3 iC32=11mW→ 25mW

u(R4)=uCE2, i(R4)= u(R4)/ R4=4.6mA

Pd(R4)= R4 i(R4)2=58mW→ 75mW ;

gm1=½(2IDSS/Vp)(1-uGS/Vp)┃=1.27mA/V

gm2=iC2/ VT= iC240=168mA/V

rbe =b/ Gm2=100/168=0.595kΩ

Figura 1

U0=(gm1uGS+gm2ube) R4║RL

ube= gm1 uGSrbe

ui= uGS+ ube+u0



u= u0 /ui=0.98

Ri=R1=10MΩ

R0=(1/gm1+ rbe)/(1+b W<100W

Calculam capacitatile la frecvente joase :

f₌√(f12+f22) f1=1/2∏R1C1 f2=1/2∏RLC2

Au(jω)=[AujωC1(R1+Rg)]/[1+jω C1(R1+Rg)] [ jωC2(RL+R0)]/[ 1+jω C2(RL+ +R0)]

Au(jω)= Au[(jf /f1)/(1+ jf /f1)] [(jf/f2)/( 1+ jf /f2)]

2f4=(f12+f2)(f22+f2) dar f≤10HZ

f1<<f2 ⇒ f1=0.1HZ ; f2≃9.9HZ

C1=1/2∏R1f1=159nF ; C2=1/2∏RLf2=16mF

La frecvente inalte

Pentru CGS u=uGS

Figura 2

-iR1║Rg=uGS+ube+( ube/rbe+gm2ube) R4║RL

i(-R1║Rg- rbe- R4║RL- rbegm2R4║RL)=u(1+ rbegm1+ gm1+

+ rbegm1gm2R4║RL)

RP1=½u/i½ W

fP1=1/2∏CGSRp1=79.6MHZ

CGS=8pF ;

Pentru CGD:

Figura6

U=iRgR1 ; RP2= Rg║R1=1kW

fP2=1/2∏CGDRp2=39.8MHZ ;

Pentru Cbe:

Figura7

Vg=0 Þii=0

ÞuGS=

gm1 uGS=0

ube=-u

(ube/rbe+i+gm2ube) R4║RL=- ube

RP3=½u/i½ W

Cbe=25pF+gm2/2∏fT=132pF

fP3=1/2∏13210-126=201MHZ ;

Pentru Cbc:

Figura8

Vg=0  ; ii=0

RP4≈1/gm1=1000/1.27≃787Ω

fP4=1/2∏810-12787=25.3MHz

Cbc=8pF

fi=1/(1/fP1+1/fP2+1/fP3+1/fP4)=12.2MHZ ;

*PROIECT DCE2

**** CIRCUIT DESCRIPTION

j1 3 2 4 j2n3819

q2 3 4 8 q2n2222

q3 4 6 7 q2n2222

r1 2 0 10Meg

r2 6 0 1.3k

r3 7 11 3.3k

r4 8 11 2.7k

rl 9 0 1k

dz1 10 6 d1n752

d1 10 11 d1n4148

c1 1 2 220n

c2 8 9 22u

vasp 3 0 12v

vasm 11 0 -12v

vg 1 0 ac 10mV sin(0 3v 1kHz)

.tran 0.25ms 5ms 0 20us

.ac dec 100 1Hz 100Meg

.op

.lib library/dce.lib

.lib library/bipolar.lib

.lib library/diode.lib

.probe

.end

**** DIODES

NAME dz1 d1

MODEL d1n752 d1n4148

ID -4.40E-03 4.40E-03

VD -5.56E+00 7.04E-01

REQ 4.25E+00 5.87E+00

CAP 4.37E-11 2.05E-09

**** BIPOLAR JUNCTION TRANSISTORS

NAME q2 q3

MODEL q2n2222 q2n2222

IB 2.57E-05 9.97E-06

IC 4.86E-03 1.69E-03

VBE 6.84E-01 6.57E-01

VBC -1.01E+01 -7.60E+00

VCE 1.08E+01 8.26E+00

BETADC 1.89E+02 1.69E+02

GM 1.85E-01 6.49E-02

RPI 1.10E+03 2.86E+03

RX 1.00E+01 1.00E+01

RO 1.73E+04 4.83E+04

CBE 1.14E-10 6.34E-11

CBC 2.93E-12 3.21E-12

CBX 0.00E+00 0.00E+00

CJS 0.00E+00 0.00E+00

BETAAC 2.03E+02 1.86E+02

FT 2.53E+08 1.55E+08

**** JFETS

NAME j1

MODEL j2n3819

ID 1.71E-03

VGS -1.86E+00

VDS 1.01E+01

GM 3.02E-03

GDS 3.77E-06

CGS 1.65E-12

CGD 6.32E-13



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