clear; clc; //Caption:Design a video amplifier using MC1550 //Given Data Avo=-25; Vagc=20;//in V Vcc=6;//in V hfe=50; rbb=50;//in ohm Cs=5;//in pF Cl=5;//in pF Ie1=1;//in mA ft=900;//in MHz Vt=26;//in V n=2;//eeta //re2 = infinity //Since Vagc=0 , transistor Q2 is in cut off region and collector current of Q1 flows through Q3....So Ie2=0; Ie3=1;//in mA re3 = (n*Vt)/Ie3;//in ohm disp('ohm',re3,'re3='); gm = (Ie1)/Vt;//in ohm^-1 disp('ohm^-1',gm,'gm='); rbe=hfe/gm; disp('ohm',rbe,'rbe='); Ce=gm/(2*%pi*ft*10^-6); disp('pF',Ce,'Ce='); a3=1;//we make an assumption that alpha is one s=0; //Av0 = -((a3*gm)/(re3*rbb))*(1/(((1/rbb)+(1/rbe)+(s*Ce))*((1/re3)+(s*Cs))*((1/Rl)+(s*(Cs+Cl))))) //From here we can find Rl k = -((a3*gm)/(re3*rbb))*(1/(((1/rbb)+(1/rbe)+(s*Ce))*((1/re3)+(s*Cs)))); Rl=Avo/k; disp('ohm',Rl,'Rl='); //C is in picoFarad so to compensate the whole equation some constants are multiplied f1 = 1/(2*%pi*Rl*(Cs+Cl)*10^-6); disp('MHz',f1,'f1='); f2 = 1/(2*%pi*Ce*10^-6*((rbe*rbb)/(rbe+rbb))); disp('MHz',f2,'f2='); f3 = 1/(2*%pi*Cs*re3*10^-6); disp('MHz',f3,'f3='); //end