Circuitul nestabilizat:

Figura1

Circuitul stabilizat:

Pentru circuitele stabilizatoare folosim modelele :

Figura3

Am ales pentru tranzistorul Tec-J modelul 2N3819:

V_p=−3V ; V_pmax=−8V

I_DSSmin=2mA ; I_DSSmax=20mA

i_D=0.8I_DSS=1.8mA.

Pentru tranzistoarele Q₂ si Q₃ modelul 2N2222

b

u_BE0=0.6V

Am ales pentru dioda zener modelul BZX55-B5V6:

u_z=5.6V

I_z=5V ;

i_D=i_C3=1.8mA - constant

i_D=I_DSS(1-u_GS/V_p)² Þ u_GS=V_p(1∓√i_D/I_DSS) Þ

u_GSmin=-0.15V

u_GSmax=-5.6V ;

u_DS≥∣u_GS-V_p∣_max Þ u_DS³7.85V

V_as⁺³u_oM-V_Pmax ³11V

½V_as^-½³u_oM+u_ZoM+u_CE3m+u_GSm=10.45V

V_as⁺= ½V_as^-½=12V

i_D=1.8mA

u_DS= V_as⁺+ u_GSmin=11.85V

ÞPSFJ₁(1.8mA ;11.85V)

Calculam rezistentele

R₁=10MW

R_L=1kW

U(R₃)=u_Z , i_D=i_C3=i_R3

u R₂)= ½V_as^-½-u_D01-u_Z=5.8V

R₂= u R₂)/i_Z=1.16 kW → 1.3 kW

i_C2 R₄║R_L=u_oM

i_C2 R₄=½V_as^-½-u_BE2-u_Gsmin Þ R₄=2.75 kW → 2.7 kW 5% , i_C2=4.2mA;

u_CE3=- u_GSmin-u_Z- V_as^-=6.55V

PSF Q₃(1.8mA ;6.55V)

u_CE2=u_DS+u_BE2=12.45V

PSF Q₂ (4.2mA ;12.45V) ;

Calculam puterile maxime disipate pe rezistente

P_d(R₂)=R₂i_Z²=29mW→ 50mW

P_d(R₃)= R₃ i_C3²=11mW→ 25mW

u(R₄)=u_CE2, i(R₄)= u(R₄)/ R₄=4.6mA

P_d(R₄)= R₄ i(R₄)²=58mW→ 75mW ;

gm₁=½(2I_DSS/V_p)(1-u_GS/V_p)┃=1.27mA/V

gm₂=i_C2/ V_T= i_C240=168mA/V

r_b'e =b/ Gm₂=100/168=0.595kΩ

Figura 1

U₀=(gm₁u_GS+gm₂u_b'e) R₄║R_L

u_b'e= gm₁ u_GSr_b'e

u_i= u_GS+ u_b'e+u₀

u= u₀ /u_i=0.98

R_i=R₁=10MΩ

R₀=(1/gm₁+ r_b'e)/(1+b W<100W

Calculam capacitatile la frecvente joase :

f₌√(f₁²+f₂²) f₁=1/2∏R₁C₁ f₂=1/2∏R_LC₂

A_u(jω)=[A_ujωC₁(R₁+R_g)]/[1+jω C₁(R₁+R_g)] [ jωC₂(R_L+R₀)]/[ 1+jω C₂(R_L+ +R₀)]

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

2f⁴=(f₁²+f²)(f₂²+f²) dar f≤10H_Z

f₁<<f₂ ⇒ f₁=0.1H_Z ; f₂≃9.9H_Z

C₁=1/2∏R₁f₁=159nF ; C₂=1/2∏R_Lf₂=16mF

La frecvente inalte

Pentru C_GS u=u_GS

Figura 2

-iR₁║R_g=u_GS+u_b'e+( u_b'e/r_b'e+gm₂u_b'e) R₄║R_L

i(-R₁║R_g- r_b'e- R₄║R_L- r_b'egm₂R₄║R_L)=u(1+ r_b'egm₁+ gm₁+

+ r_b'egm₁gm₂R₄║R_L)

R_P1=½u/i½ W

f_P1=1/2∏C_GSR_p1=79.6MH_Z

C_GS=8pF ;

Pentru C_GD:

Figura6

U=iR_g║R₁ ; R_P2= R_g║R₁=1kW

f_P2=1/2∏C_GDR_p2=39.8MH_Z ;

Pentru C_b'e:

Figura7

V_g=0 Þi_i=0

Þu_GS=

gm₁ u_GS=0

u_b'e=-u

(u_b'e/r_b'e+i+gm₂u_b'e) R₄║R_L=- u_b'e

R_P3=½u/i½ W

C_b'e=25pF+gm₂/2∏f_T=132pF

f_P3=1/2∏13210^-126=201MH_Z ;

Pentru C_b'c:

Figura8

V_g=0  ; i_i=0

R_P4≈1/gm₁=1000/1.27≃787Ω

f_P4=1/2∏810^-12787=25.3MH_z

C_b'c=8pF

f_i=1/(1/f_P1+1/f_P2+1/f_P3+1/f_P4)=12.2MH_Z ;

*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