z1=32+45*i
z2=14+17*i
z3=250000*30000*i/(250000+30000*i)
for a=0:5:500
for b=-300:5:300 如果点多的话,计算会很慢
z4=a+b*i
zs=z1+(z2+z4)*z3/(z3+z4+z2)
i4=8000/zs-(8000-z1*8000/zs)/z3
u4=i4*z4
S=u4*i4'
z=real(S)
plot3(a,b,z);hold on;
end
end
clear;clc
[a b]=meshgrid(-3:0.5:3);
z1=32+45*i;
z2=14+17*i;
z3=250000*30000*i/(250000+30000*i);
z4=a+b*i;
zs=z1+(z2+z4)*z3./(z3+z4+z2);
i4=8000./zs-(8000-z1*8000./zs)/z3;
u4=i4.*z4;
S=u4.*i4';
z=real(S);
mesh(a,b,z)