//chapter 12
//example 12.7
//page 489
printf("\n")
printf("given")
R1=120*10^3;R2=39*10^3;hie=2*10^3;R7=12*10^3;Zo=R7;R5=R1;R6=R2;hfe=100;R3=R7;Zl=R1;
Zi=(R1*R2*hie)/(R1*R2+R1*hie+R2*hie)
Zi2=(R1*R2*hie)/(R1*R2+R1*hie+R2*hie)
Av1=-(hfe*((R3*Zi2)/(R3+Zi2)))/hie
Av2=-(hfe*((R7*Zl)/(R7+Zl)))/hie
Av=Av1*Av2