04 Diode Cond Permanenta Ro

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Valoarea curentului care trece prin dioda este determinata de caderea de tensiune pe dioda

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)1( = TD

nVv

SD eIi IS - curentul de satura ie

qKTVT = tensiunea termica

25=TV la temp ambianta(aprox 20O C)

n=2 pentru diode discrete n=1 pentru diode din CI

SD Ii >>

T

D

nVv

SD eIi

3RODUL]DUH GLUHFW

T

D

nVv

SD eIi IS, VT - depind direct de temperaturala curent constant, la o cretere a temperaturii cu10C , tensiunea pe diodscade cu 2mV

C2mV/=CT

cstIDD DTTCTTvTv

+= )()()( 1212

'HSHQGHQ DGH WHPSHUDWXU

ID=? VD=?

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$QDOL]DFLUFXLWHORUFXGLRGH

0HWRGDJUDILF

0HWRGDJUDILF

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9' ,' VROX LD LQLWLDOD

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0HWRGDDQDOLWLF

VVD 7,0)0(

=

V635,0nA14mA6,4ln025,02ln

)0()1(

===

S

DTD I

InVV

mA73,45,0635,03)1()1(

=

=

=

RVVI DID

6H FRQVLGHUD9, 95 .LDU 'HVWH1[FX,6 Q$LQ

RVVI DID

=

S

DTD I

InVV ln=

6,45,0

7,03)0(=

=DI mA

0HWRGDDQDOLWLF ([HPSOX

V637,0nA14mA73,4ln025,02ln

)1()2(

===

S

DTD I

IVnV

mA726,45,0637,03)2()2(

=

=

=

RVVI DID

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3DUDPHWULLVWDWLFL

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DD I

Vr =

D

D

DD V

Ir

g == 1

Exemplu:

Q1(0,7V; 16,8mA)

Q2(0,65V; 2,3mA)

== 428,16

7,01Dr

== 2833,2

65,02Dr

gD1=24mS

gD2=3,5mS

FRQGXFWDQ D VWDWLF DGLRGHL

$SUR[LPDUHDGHVHPQDOPLFUHJLXQHOLQLDU LQMXUXOOXL4

3DUDPHWULLGLIHUHQ LDOL GHVHPQDOPLFvD(t)= VD+vd(t)iD(t)=ID+id(t)

8QVHPQDOYDULDELOPLFHVWHVXSUDSXVSHVWHPDULPLOHGHFF

Qd

dd i

vr =

D

Td I

nVr =

Rezistenta diferentiala:

Interpretarea rD i rd

0RGHODUHD GLRGHL LQ36)semnal mic (variatii)curent continuu

'LRGD =HQHU

Z

Z

Z

Z

Z

Ii

Vv

F

=

Z

zZ

r

rF =

)DFWRUXOUHODWLYGHVWDELOL]DUHDO'=

3HQWUXWUHL GLRGHGH:OD DFHODLFXUHQW QRPLQDOIZ = 5 mA avem :1) DZ 3V6 VZ = 3,6V; rzmax = 95; rZ = 0,72 K2) DZ 5V1 VZ = 5,1V; rzmax = 60; rZ = 1,02 K3) DZ 10 VZ = 10V; rzmax = 15; rZ = 2 K

132,072095

1 ==ZF

059,01020

602 ==ZF

0075,0200015

3 ==ZF

([HPSOX

Z

dZ V

PI maxmax =

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$SOLFD LL DOH'=

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6WDELOL]DWRU SDUDPHWULFGH WHQVLXQH

VO = vI vstabilizator

6WDELOL]DWRU SDUDPHWULFGHWHQVLXQH

OZI

Z IRVv

i

=

maxmin

Immax

OZ

Zin

IIVV

R+

=

minmax

Immin

OZ

Zax

IIVV

R+

=

minmax

L

ZO R

VI =

max

minL

ZO R

VI =

R ( Rmin ; Rmax )

6WDELOL]DWRU SDUDPHWULFGHWHQVLXQH

I

I

O

o

V

Vv

Vv

F

=

RRrRr

v

v

Lz

Lz

I

O

+

////

LZ

LZ

O

I

R//rRR//r

VV +

=

RrRr

r

rF

z

Z

Z

zV +

+=

ZLZLZ

zLzLz

rRrRrrRrRr

Io

/LPLWDWRDUHGXEOH GH WHQVLXQH

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