Etaj de amplificare elementar cu tranzistor bipolar ... - scs.etc.tuiasi.ro
Etaj de amplificare elementar cu tranzistor bipolar ... - scs.etc.tuiasi.ro
Etaj de amplificare elementar cu tranzistor bipolar ... - scs.etc.tuiasi.ro
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<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în<br />
conexiune colector comun (repetorul pe emitor)<br />
Cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itul echivalent natural π - hibrid (Giacoletto).........................................................................1<br />
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> polarizare <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> TB in conexiune colector comun (repetorul pe emitor) ................................2<br />
Analiza <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> punct static <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> functionare ........................................................................................2<br />
Raspunsul cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului la frecvente medii.....................................................................................2<br />
Raspunsul cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului la joasa frecventa......................................................................................4<br />
Raspunsul cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului la înalta frecventa .....................................................................................5<br />
Simulare SPICE...............................................................................................................................6<br />
Punctul static <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> functionare (PSF) si parametrii <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>l pentru <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>:............................6<br />
Diagrame Bo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> modul si faza ................................................................................................7<br />
Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>l simbolic................................................................................................................................7<br />
PSF ..............................................................................................................................................7<br />
Analiza la semnal mic .................................................................................................................8<br />
Ap<strong>ro</strong>ximarea in banda .............................................................................................................9<br />
Ap<strong>ro</strong>ximarea la joasa frecventa...............................................................................................9<br />
Ap<strong>ro</strong>ximarea la frecventa inalta ............................................................................................10<br />
Cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itul echivalent natural p - hibrid (Giacoletto)<br />
Fig. 1. Mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>lul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic natural π - hibrid al <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>ului <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng><br />
Este cel mai utilizat cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>it echivalent <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic, valabil in toate conexiunile in care poate<br />
functiona <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>ul <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng>. Elementele sale au semnificatii fizice clare, nu <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>pind <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> frecventa<br />
si pot fi <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>terminate usor experimental.<br />
Parametrii principali ai cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului π - hibrid sunt:<br />
IC<br />
1. Transconductanta (panta): gm= ≃ 40 IC( mA/ V)<br />
, <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> IC[ mA ] .<br />
U<br />
2. Rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare:<br />
β<br />
rπ<br />
=<br />
gm<br />
3. Rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> iesire:<br />
U A r0<br />
≃ în care UA este tensiunea Early.<br />
IC<br />
4. Rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> reactie (colector-baza): rμ= β r0<br />
T<br />
TB – CC - 1
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> polarizare <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> TB in conexiune colector comun<br />
(repetorul pe emitor)<br />
În schema din Fig.2 este etajul in conexiune colector comun (<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>numit uzual si repetor pe<br />
emitor). Colectorul <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>ului este <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>plat direct la sursa <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> alimentare EC, <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ci pe semnal este<br />
la potentialul masei. Semnalul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> la iesire se preia din emitor prin con<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>nsatorul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>plaj CC.<br />
Rezistenta RS reprezinta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> regula rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare în urmatorul etaj <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>, iar sursa<br />
<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal reala <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> la intrare <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> rezistenta Rg reprezinta iesirea etajului <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> anterior.<br />
TB – CC - 2<br />
Fig. 2. <st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> în conexiune colector comun (repetor pe emitor)<br />
Analiza <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> punct static <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> functionare<br />
Schema <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> polarizare este similara <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> cea folosita in montajul emitor comun. Pentru<br />
<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>terminarea <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rentului <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> colector si a tensiunii colector – emitor se foloseste modul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>l<br />
<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>scris. Curentul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> colector este:<br />
un<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng><br />
R<br />
E = E<br />
B2<br />
B1 B2<br />
B C si RB<br />
=<br />
RB1+ RB2<br />
RB1+ RB2<br />
I<br />
C<br />
( E −V<br />
B BE )<br />
+ ( β + 1)<br />
β<br />
≃<br />
R R<br />
R R<br />
B E<br />
V = E −RI E −RI<br />
. Tensiunea colector-emitor este:<br />
CE C E E C E C<br />
III. 1<br />
≃ III. 2<br />
Relatiile se pot utiliza pentru <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>terminarea rapida a punctului static <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> functionare (PSF).<br />
Raspunsul cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului la frecvente medii<br />
Fig. 3. Schema <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic a repetorului pe emitor<br />
Pe schema <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic a cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului din Fig.3 se pot scrie relatiile:<br />
V = ( β + 1 )( R || R ) I<br />
III. 3<br />
o E S b<br />
S
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
( ) ( β 1 )( || )<br />
V = r + r I + + R R I<br />
III. 4<br />
i π x b E S b<br />
Se obtine urmatoarea expresie a amplificarii fata <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare:<br />
V ( β + 1 )( R || R<br />
o<br />
E S)<br />
Aui<br />
= =<br />
V r + r + β + 1 R || R<br />
i π x ( )( E S)<br />
Pentru valori uzuale ale elementelor schemei, avem ( 1 )( || )<br />
E S π x<br />
III. 5<br />
β + R R >> r + r si <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ci<br />
<st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>a rezulta subunitara, dar foarte ap<strong>ro</strong>ape <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> 1: Aui ≈ 1.<br />
Repetorul pe emitor se<br />
utilizeaza ca etaj tampon între doua etaje <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> în tensiune, datorita valorilor rezistentei<br />
<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare si <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> iesire. El joaca <strong>ro</strong>lul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> adaptor <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> impedanta, evitând pier<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>rea <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> tensiune <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng><br />
semnal pe rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> iesire la <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>plajul între doua etaje <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>plate în cascada. Astfel, la <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>plarea<br />
prin repetor a mai multor etaje, <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>a întregului lant <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> este practic egala <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng><br />
p<strong>ro</strong>dusul amplificarilor etajelor componente.<br />
Rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare în <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> rezulta imediat:<br />
Vi<br />
Rit = = rπ+ rx + ( β + 1 )( RE || RS)<br />
III. 6<br />
Ib<br />
Se observa ca pentru valori uzuale, R it rezulta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> ordinul sutelor <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> kO.<br />
Rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare în etaj <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>prin<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> si rezistentele <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> polarizare din baza:<br />
Ri = Rit || RB || RB ≅ R B || RB<br />
III. 7<br />
1 2 1 2<br />
Fig. 4. Schema echivalenta pentru cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lul rezistentelor <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> iesire<br />
Rezistentele <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> iesire din <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> respectiv din etaj se pot cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>la <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> pe schema echivalenta din<br />
Fig.4, în care etajul s-a pasivizat la intrare iar sarcina (rezistenta RS ) este înlo<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>ita <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> o sursa <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng><br />
semnal <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> test Ut, care da <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rentul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> test It.<br />
Se poate exprima <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rentul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> test It astfel:<br />
Ut Ut Ut<br />
It<br />
= = + ( β + 1)<br />
Ro RE rπ+ rx + Rg <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> un<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> rezulta rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> iesire din etaj:<br />
|| RB<br />
III. 8<br />
U ( r || )<br />
t<br />
π + rx + Rg RB<br />
Ro = = RE || = RE || Rot ≅ Rot<br />
It<br />
( β + 1)<br />
în care R ot este rezistenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> iesire din emitorul <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>ului.<br />
Deoarece în general Rot
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
Raspunsul cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului la joasa frecventa<br />
In schema <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic a etajului în conexiune colector comun (repetor pe emitor) apar<br />
con<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>nsatoarele <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>plaj CB si CS (în baza si <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> sarcina RS }).<br />
Fig. 5. Schema echivalenta a repetorului pe emitor la frecvente joase<br />
Vom analiza comportarea etajului la frecvente joase, la care reactantele celor doua con<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>nsatoare<br />
<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>plaj nu mai sunt neglijabile. Am notat <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> ZB si ZE impedantele vazute în baza si respectiv în<br />
emitorul <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>ului.<br />
Impedanta ZE are expresia:<br />
⎛ 1 ⎞<br />
RE ⎜RS + ⎟<br />
sCS RE( 1+<br />
sRSCS) ZE( s)<br />
=<br />
⎝ ⎠<br />
=<br />
1<br />
R<br />
1 s( R R ) C<br />
E + RS<br />
+<br />
+ +<br />
sCS<br />
Tensiunea la iesire se poate exprima:<br />
RS sRSCS Vo = VE = VE<br />
1<br />
R<br />
1 sRSCS S +<br />
+<br />
sC<br />
S<br />
Tensiunile Vi si VE se pot scrie în functie <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>renti:<br />
TB – CC - 4<br />
( π ) ( β 1)<br />
( )<br />
( β 1)<br />
( )<br />
V = r + r I + + IZ s<br />
i x b b E<br />
E S S<br />
VE = + IZ b E s<br />
Se obtine raportul:<br />
V ( β + 1)<br />
Z ( s<br />
E<br />
E )<br />
=<br />
Vi rπ+ rx + ( β + 1)<br />
ZE( s)<br />
care se scrie <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>taliat sub forma urmatoare:<br />
V<br />
( β + 1) R ( 1+<br />
sR C<br />
E<br />
E S S)<br />
=<br />
Vi rπ + rx + ( β + 1 ) RE + sCS[ ( RE+ RS)( rπ + rx) + ( β + 1 ) RR E S]<br />
Amplificarea fata <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare va avea expresia:<br />
V ( 1<br />
o Vo V<br />
β + ) RRC E S S ⋅s<br />
E<br />
Avi ( s)<br />
= = ⋅ =<br />
Vi VE Vi rπ + rx + ( β + 1) RE + sCS ⎡⎣( RE + RS)( rπ + rx) + ( β+<br />
1)<br />
RR E S⎤⎦<br />
Daca se <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>fineste pulsatia:<br />
rπ+ rx+ ( β + 1)<br />
RE<br />
ω1<br />
=<br />
⎡⎣( RE + RS)( rπ+ rx) + ( β + 1)<br />
RR E S⎤⎦CS <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>a se poate scrie:<br />
( β + 1)<br />
RR E S<br />
s<br />
Avi ( s)<br />
= ⋅<br />
( RE + RS )( rπ+ rx) + ( β + 1)<br />
RR E S s+<br />
ω1<br />
Impedanta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare este:<br />
III. 10<br />
III. 11<br />
III. 12<br />
III. 13<br />
III. 14<br />
III. 15<br />
III. 16<br />
III. 17
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
( β + 1) R ( 1+<br />
sR C<br />
E S S)<br />
1+<br />
( + )<br />
Vi<br />
Z ( s) = = r + r<br />
I<br />
+ ( β + 1)<br />
Z ( s) = r + r +<br />
s R R C<br />
Se poate exprima si raportul fata <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> tensiunea sursei:<br />
Vi<br />
V<br />
sCB( RB|| Zi)<br />
=<br />
1 + sC R + R || Z<br />
i π x E π x<br />
b E S S<br />
( )<br />
g B g B i<br />
dar explicitarea sa duce la o expresie <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>stul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> complicata.<br />
III. 18<br />
III. 19<br />
Raspunsul cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului la înalta frecventa<br />
În Fig.6 se da schema echivalenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal la frecvente înalte a repetorului pe emitor, în care<br />
apar capacitatile interne ale <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>ului.<br />
Fig. 6. Schema echivalenta a repetorului pe emitor la frecvente înalte<br />
Se observa ca atât capacitatea Cμ cât si rezistenta p<strong>ro</strong>prie <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> iesire a <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>ului <strong>ro</strong> au un capat<br />
la masa pe semnal; schema se poate reprezenta mai simplu ca mai jos:<br />
Fig. 7. Schema echivalenta simplificata<br />
In aceasta schema se observa ca etajul este unilateralizat, <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ci nu mai exista reactie interna.<br />
Rezistenta parazita rx nu mai apare în schema, având o valoare neglijabila si complicând inutil<br />
expresia amplificarii etajului.<br />
Rezistentele RE , RS si <strong>ro</strong> formeaza o rezistenta echivalenta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> sarcina R ’ S:<br />
'<br />
Rs RE || RS || <strong>ro</strong> RE || RS<br />
Din baza pâna la masa se poate scrie relatia:<br />
un<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>Y<br />
π<br />
= ≅ III. 20<br />
( π )<br />
V = V + R YV + gV<br />
III. 21<br />
i '<br />
be<br />
'<br />
s '<br />
be m '<br />
be<br />
1<br />
= este admitanta grupului rπ -Cπ din baza. Expresia <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> mai sus <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>vine:<br />
Z<br />
π<br />
( ) '<br />
'<br />
V = ⎡1 i ⎣<br />
+ Rs g + g m π + sCπ ⎤<br />
⎦<br />
V<br />
be<br />
III. 22<br />
Tensiunea la iesire este:<br />
V<br />
'<br />
= R g + Y V '<br />
'<br />
= R g + g + sC V '<br />
III. 23<br />
( ) ( )<br />
o s m π be s m π π be<br />
Se obtine <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>a etajului fata <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare:<br />
TB – CC - 5
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
TB – CC - 6<br />
( + π + π)<br />
' ( )<br />
'<br />
V Rs g o<br />
m g sC<br />
Avi ( s)<br />
= =<br />
Vi 1+<br />
Rs gm + gπ + sCπ<br />
Schema echivalenta la intrare daca se înlo<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>ieste etajul <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> impedanta sa echivalenta Zi este:<br />
Fig. 8. Schema echivalenta raportata la intrare<br />
Impedanta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> intrare în baza se poate scrie:<br />
'<br />
V 1 i V + R i<br />
s( gm + gπ + sCπ)<br />
Zi( s)<br />
= = =<br />
I YV g + sC<br />
π π '<br />
be<br />
π π<br />
III. 24<br />
III. 25<br />
Admitanta echivalenta totala vazuta <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> sursa <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal este:.<br />
Yech ( s) = gB + sCμ + Yi( s) = gB + sCμ<br />
gπ + sCπ<br />
+ '<br />
1+<br />
Rs( gm + gπ + sCπ)<br />
III. 26<br />
Se poate atunci scrie si <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>a fata <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> tensiunea sursei <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal, dar expresia finala<br />
explicitata rezulta complicata:<br />
Vo Vo Vi<br />
Avg ( s) = = ⋅<br />
V V V<br />
Gg<br />
=<br />
G + Y<br />
Avi ( s)<br />
III. 27<br />
Simulare SPICE<br />
g i g g ech<br />
Punctul static <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> functionare (PSF) si parametrii <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>l pentru<br />
<st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>:<br />
MODEL BC107A<br />
IB 9.09E-06<br />
IC 1.59E-03<br />
VBE 6.75E-01<br />
VBC -4.05E+00<br />
VCE 4.73E+00<br />
BETADC 1.75E+02<br />
GM 6.14E-02<br />
RPI 3.24E+03<br />
RX 0.00E+00<br />
RO 7.58E+04<br />
CBE 4.80E-11<br />
CBC 2.77E-12<br />
CJS 0.00E+00<br />
BETAAC 1.99E+02<br />
CBX/CBX2 0.00E+00<br />
FT/FT2 1.92E+08
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
Diagrame Bo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> modul si faza<br />
0<br />
-10<br />
-20<br />
-30<br />
-40<br />
10mHz 1.0Hz 100Hz 10KHz 1.0MHz 100MHz 10GHz 1.0THz 100THz<br />
DB(V(Rs:2)/V(Q3:b))<br />
Frequency<br />
100d<br />
50d<br />
0d<br />
10mHz 1.0Hz 100Hz 10KHz 1.0MHz 100MHz 10GHz 1.0THz 100THz<br />
P(V(Rs:2)/V(Q3:b))<br />
Frequency<br />
Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>l simbolic<br />
PSF<br />
> restart:with(Syrup):libname:="c:\\maple/SCSlib",libname:<br />
Schema <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic valabila in toata gama <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> frecvente:<br />
> TB_CC:=<br />
"schema pentru TB in conexiune CC<br />
Vcc vcc 0 Vcc<br />
Vg ing 0 Vg<br />
Rg ing inc Rc<br />
Cb inc In Cb<br />
Rb1 vcc In Rb1<br />
Rb2 In 0 Rb2<br />
Qnpn vcc In e BJT[pnp_dc_generic_mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>l]<br />
Rem e 0 Rem<br />
Cs e Out Cs<br />
Rs Out 0 Rs<br />
.end":<br />
Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lul simbolic:<br />
TB – CC - 7
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
> syrup(TB_CC, dc, '<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rr','tens'):<br />
Syrup/parse<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ck: Analyzing SPICE <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ck "schema pentru TB in conexiune CC"<br />
(ignoring this line)<br />
syrup: There may be an unconnected component.<br />
The following component(s) have ze<strong>ro</strong> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rrent: {Vg, Rg, Rs}.<br />
Curentul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> colector:<br />
> collect(simplify(eval(i[Rem],<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rr)),{Vcc,Vd});<br />
( Rb2 β + Rb2 ) Vcc<br />
dc<br />
TB – CC - 8<br />
Rb2 Rb1 + Rem β Rb1 + Rb1 Rem + Rb2 β Rem + Rem Rb2<br />
dc dc<br />
+<br />
( Rb2 β + Rb2 + β Rb1 + Rb1 ) Vd<br />
dc dc<br />
Rb2 Rb1 + Rem β Rb1 + Rb1 Rem + Rb2 β Rem + Rem Rb2<br />
dc dc<br />
Tensiunea colector - emitor:<br />
> collect(simplify(eval(Vcc-v[e],tens)),{Vcc,Vd});<br />
( Rb2 Rb1 + Rem β Rb1 + Rb1 Rem ) Vcc<br />
dc<br />
Rb2 Rb1 + Rem β Rb1 + Rb1 Rem + Rb2 β Rem + Rem Rb2<br />
dc dc<br />
+<br />
( − Rb2 β Rem − Rem Rb2 − Rem β Rb1 − Rb1 Rem ) Vd<br />
dc dc<br />
Rb2 Rb1 + Rem β Rb1 + Rb1 Rem + Rb2 β Rem + Rem Rb2<br />
dc dc<br />
Neglijind <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rentul din baza ( β dc mare) putem cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>la <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rentul <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> colector si tensiunea colector-<br />
emitor:<br />
> limit(eval(i[Rc],<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rr),beta[dc]=infinity);<br />
i Rc<br />
>collect(simplify(limit(eval(Vcc-v[e],tens),beta[dc]=infinity)),<br />
{Vcc,Vd});<br />
Rb1 Vcc ( − Rb1 − Rb2 ) Vd<br />
+<br />
Rb1 + Rb2 Rb1 + Rb2<br />
Analiza la semnal mic<br />
> restart:with(Syrup):libname:="c:\\maple/SCSlib",libname:<br />
Schema <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic valabila in toata gama <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> frecvente:<br />
> TB_CC:=<br />
"schema <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic pentru TB in conexiune CC<br />
Vcc vcc 0 0<br />
Vg ing 0 Vg<br />
Rg ing inc Rc<br />
Cb inc In Cb<br />
Rb1 vcc In Rb1<br />
Rb2 In 0 Rb2<br />
Qnpn vcc In e BJT[ac_generic_mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>l]<br />
Rem e 0 Rem<br />
Cs e Out Cs<br />
Rs Out 0 Rs<br />
.end":<br />
Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lul simbolic:<br />
> syrup(TB_CC, ac, '<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rr','tens'):<br />
Syrup/parse<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ck: Analyzing SPICE <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ck "schema <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> semnal mic pentru TB in<br />
conexiune CC" (ignoring this line)<br />
Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lul functiei <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> transfer:<br />
> H:=eval(v[Out]/v[In],tens):
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
Expresia functiei <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> transfer este complicata. Exista 3 poli si 2 ze<strong>ro</strong>uri care <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>termina<br />
comportarea cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itului in toata gama <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> frecventa. Se analizeaza cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itul simplificat in banda,<br />
la joasa frecventa si la inalta frecventa.<br />
Ap<strong>ro</strong>ximarea in banda<br />
se consi<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ra s<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rt cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>it la frecventa <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> lucru capacitatile: Cb, Ce, Cs;<br />
se neglijeaza din mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>lul π − hibrid capacitatile Cpi (sc), Cmiu (gol) si rezistentele<br />
rmiu(gol) si <strong>ro</strong>(gol);<br />
> eval(v[Out]/v[In],tens):<br />
limit(%,{Cs=infinity,Cb=infinity,Cem=infinity}):<br />
limit(%,{cpi=0,cmiu=0, co=0,rmiu=infinity,<strong>ro</strong>=infinity}):<br />
Hs:=simplify(%);<br />
Rs Rem ( 1 + rpi gm)<br />
Hs :=<br />
Rem rx + gm rpi Rem Rs + Rem Rs + Rs rx + rpi Rem + rpi Rs<br />
Daca neglijam rezistenta rx, <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>a este:<br />
> limit(%,{rx=0});limit(%,{rpi=0});<br />
Rs Rem ( 1 + rpi gm)<br />
gm rpi Rem Rs + Rem Rs + rpi Rem + rpi Rs<br />
1<br />
Ap<strong>ro</strong>ximarea la joasa frecventa<br />
se iau in consi<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ra la frecventa <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> lucru capacitatile Cb, Ce, Cs;<br />
se neglijeaza din mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>lul<br />
π − hibrid<br />
capacitatile Cpi (sc), Cmiu (gol) si rezistentele<br />
rmiu(gol) si <strong>ro</strong>(gol);<br />
> eval(v[Out]/v[In],tens):<br />
limit(%,{cpi=0,cmiu=0,co=0,rmiu=infinity,<strong>ro</strong>=infinity}):<br />
Hs:=simplify(%):<br />
Expresia lui Hs este un raport <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> doua polinoame in s.<br />
• Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lam polii functiei <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> transfer Hs:<br />
> solve(collect(<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>nom(Hs),s)=0,s);<br />
gm rpi Rem + Rem + rx + rpi<br />
−<br />
Cs ( Rem rx + gm rpi Rem Rs + Rem Rs + Rs rx + rpi Rem + rpi Rs )<br />
• Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lam ze<strong>ro</strong>urile functiei <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> transfer Hs:<br />
> solve(collect(numer(Hs),s)=0,s);<br />
0<br />
• Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lam <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>a in <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>rent continuu Aui0:<br />
> limit(subs(s=I*omega, Hs),omega=0);limit(%,rx=0);<br />
0<br />
0<br />
Mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>lul este valabil numai pentru joasa frecventa. Daca crestem frecventa ar trebui sa regasim<br />
formula amplificarii in banda:<br />
> limit(subs(s=I*omega,<br />
Hs),omega=infinity);limit(%,rx=0);limit(%,rpi=0);<br />
( 1 + rpi gm) Rem Rs<br />
Rem rx + gm rpi Rem Rs + Rem Rs + Rs rx + rpi Rem + rpi Rs<br />
TB – CC - 9
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
( 1 + rpi gm ) Rem Rs<br />
gm rpi Rem Rs + Rem Rs + rpi Rem + rpi Rs<br />
TB – CC - 10<br />
1<br />
Ap<strong>ro</strong>ximarea la frecventa inalta<br />
se iau in consi<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>ra la frecventa <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> lucru capacitatile Cb, Ce, Cs;<br />
se neglijeaza din mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>lul<br />
π − hibrid<br />
capacitatile Cpi (sc), Cmiu (gol) si rezistentele<br />
rmiu(gol) si <strong>ro</strong>(gol);<br />
> eval(v[Out]/v[In],tens):<br />
limit(%,{Cs=infinity,Cb=infinity,Cem=infinity}):<br />
limit(%,{rmiu=infinity,<strong>ro</strong>=infinity}):<br />
Hs:=simplify(%):<br />
Expresia lui Hs este un raport <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> doua polinoame in s.<br />
• Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lam ze<strong>ro</strong>urile functiei <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> transfer Hs:<br />
> solve(collect(numer(Hs),s)=0,s);<br />
− + 1 rpi gm<br />
cpi rpi<br />
• Cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lam polii functiei <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> transfer Hs:<br />
> simplify({solve(collect(<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>nom(Hs),s)=0,s)}):<br />
> collect(<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>nom(Hs),s):<br />
S-au gasit doi poli a ca<strong>ro</strong>r valoare nu este intuitiva.<br />
Daca neglijam rezistenta rx atunci cir<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>itul are un singur pol:<br />
> solve(collect(<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>nom(limit(Hs,rx=0)),s)=0,s);<br />
rpi Rs + Rem Rs + gm rpi Rem Rs + rpi Rem<br />
−<br />
cpi rpi Rem Rs<br />
• Mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>lul este valabil pentru inalta frecventa. Daca sca<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>m frecventa ar trebui sa regasim<br />
formula amplificarii in banda:<br />
>limit(subs(s=I*omega, Hs),omega=0);limit(%,rx=0);limit(%,rpi=0);<br />
( 1 + rpi gm) Rem Rs<br />
Rem rx + gm rpi Rem Rs + Rem Rs + Rs rx + rpi Rem + rpi Rs<br />
( 1 + rpi gm ) Rem Rs<br />
rpi Rs + Rem Rs + gm rpi Rem Rs + rpi Rem<br />
• Neglijind rezistenta rx cal<st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng>lam <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng>a la frecventa mare:<br />
> limit(subs(s=I*omega, limit(Hs,rx=0)),omega=infinity);<br />
1<br />
1<br />
Pentru valorile <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> mo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>l ale <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>ului <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng>terminate in analiza Spice se traseaza diagrama<br />
Bo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> modul si faza.<br />
> H1:=limit(H, {rmiu=infinity}):<br />
> schema := {Rem=3300, Rs=2000 , Cs=10^(-4)};<br />
1<br />
schema := { Rem = 3300 , Rs = 2000 , Cs = }<br />
10000<br />
> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng>:={gm=0.0614, rx=0, rpi=3240, cpi=4.80*10^(-11) ,<br />
cmiu=2.77*10^(-12) , <strong>ro</strong>=7.58*10^4 };
<st<strong>ro</strong>ng>Etaj</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>amplificare</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>elementar</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>cu</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>bipolar</st<strong>ro</strong>ng> în conexiune colector comun<br />
<st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> cmiu = .2770000000 10 -11<br />
rx = 0 cpi = .4800000000 10 -10<br />
:= {<br />
, , , rpi = 3240,<br />
gm = .0614 , <strong>ro</strong> = 75800.00 }<br />
> Hs:=simplify(eval(H1,schema union <st<strong>ro</strong>ng>tranzistor</st<strong>ro</strong>ng> ));<br />
s ( 243. s + .3124000000 10 )<br />
Hs := 4169.<br />
12<br />
.1319622449 10 + +<br />
16 s .1013067 107 s2 .6545348312 1016 > PZ[numeric](Hs,s);<br />
⎡z1<br />
0. ⎤<br />
⎢<br />
⎥<br />
⎢<br />
⎢z2<br />
-.1285 10 ⎥<br />
⎢<br />
⎥<br />
⎢<br />
⎥<br />
⎢<br />
⎥<br />
⎢<br />
⎥<br />
⎣<br />
⎦<br />
10<br />
p1 -4.958<br />
p2 -.1303 10 10<br />
>plot({[log10(omega),20*log10(abs(subs(s=I*omega,Hs))),omega=10^(<br />
-1)..10^3],[log10(omega),20*log10(abs(subs(s=I*omega,Hs))),omega<br />
=10^3..10^8],[log10(omega),20*log10(abs(subs(s=I*omega,Hs))),ome<br />
ga=10^8..10^12]},numpoints=300,color=black,thickness=2,title="Di<br />
agrama Bo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> <st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> castig");<br />
> plot({[log10(omega),argument(subs(s=I*omega,Hs)),omega=10^(-<br />
1)..10^3],[log10(omega),argument(subs(s=I*omega,Hs)),omega=10^3.<br />
.10^8],[log10(omega),argument(subs(s=I*omega,Hs)),omega=10^8..10<br />
^12]},numpoints=300,color=black,thickness=2,title="Diagrama Bo<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng><br />
<st<strong>ro</strong>ng>de</st<strong>ro</strong>ng> faza");<br />
TB – CC - 11