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clear;
clc;
//Caption : Program to find transistor currents for npn transistor and check whether transistor is in saturation region or not after adding a Emitter Transistor.
//Given Values
//Silicon Transistor
Beta=100; //Beta
Rc=3;
Rb=50;
Re=2;
Vbb=5; //in V
Vcc=10; //in V
Vce=0.2; //in V
Vbe=0.8; //in Active region
hFE=100;
//Assuming transistor in saturated region
//Applying KVL to base circuit
//-Vbb+Rb*Ib+Vbe+Re*(Ic+Ib)=0
//Simplifing (Rb+Re)Ib+Re*Ic=Vbb-Vbe
//Applying KVL to Collector circuit
//-Vcc+Rc*Ic+Vce+Re*(Ic+Ib)=0
//Simplifing Re*Ib+(Rc+Re)Ic=Vcc-Vce
A=[(Rb+Re) Re;Re,(Rc+Re)];
B=[(Vbb-Vbe);(Vcc-Vce)];
X=A\B;
Ib=X(1);
Ic=X(2);
Ib_min=Ic/hFE;
disp('mA',Ib_min,'Minimum Ib = ');
disp('mA',Ic,'Current in transistor(Ic)');
disp('mA',Ib,'Current in transistor(Ib)');
if(Ib>Ib_min)
disp('Transistor in Saturated Region');
else
disp('Transistor not in Saturated Region.Hence must be operating in Active region');
end
//Ico<<Ib Assuming
//Itot=Ib+Ic=Ib+B*Ib=(B+1)*Ib
//Applying KVL to base circuit
//Vbb+Rb*Ib+Vbe+Re*Itot=0
Ib=(Vbb-Vbe)/(Rb+(Re*(Beta+1))); //in mA
Ic=Beta*Ib; //in mA
//Hence Ico<<Ib
//To verify the Active region Assumption
//Vcc+Rc*Ic+Vcb+Vbe=0
Vcb=(-Rc*Ic)+Vcc-Vbe-(Re*(Beta+1)*Ib); //in V
disp('V',Vcb,'Vcb = ');
if(Vcb>0)
disp('Positive value of Vcb represents reversed biased collector junction and Transistor in active region');
end
disp('mA',Ic,'Current in transistor(Ic) is ');
disp('mA',Ib,'Current in transistor(Ib) is ');
//End
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