%《MATLAB及其在理工課程中的應(yīng)用指南》(十一五規(guī)劃版)第八章例8－2－2程序
% 晶體管放大器低頻等效電路分析
% 西安電子科技大學(xué)出版社出版  陳懷琛編著 2007年7月
%
clear
w=logspace(0,3);
C1=1e-5;rs=100;rb=1e4;
hie=1000;hfe=100;us=1;
re=200; Ce=1e-4; rc=1000; 
C2=1e-5; rL=2000; 
for C2=[C2,10*C2]
   Ce=1e-4;
   for Ce=[Ce,10*Ce]
      for i=1:length(w)
         s=j*w(i);
         a11=1/rs+s*C1; 
         a12=-s*C1;
         a21=-s*C1;
         a22=s*C1+1/rb+1/hie;
         a23=-1/hie;
         a32=(1+hfe)/hie;
         a33=-((1+hfe)/hie+1/re+s*Ce);
         a42=hfe/hie;
         a43=-hfe/hie;
         a44=-(1/rc+s*C2./(rL*C2*s+1));
         a=[a11,a12,0,0;a21,a22,a23,0;0,a32,a33,0;0,a42,a43,a44];
         b=[us/rs;0;0;0];
         x=a\b;
         u(:,i)=x;
      end
      s=j*w;uL=u(4,:).*rL./(rL+1./(C2*s));
      loglog(w,abs(uL)),grid,hold on
   end
end
hold off,grid on
set(gcf,'color','w')