作业补充1
1. p(t)=2UIsin2wt
P=UI
2. p(t)=-UIsin(2wt)
P=0
3. p(t)=UIsin(2wt)
P=0
4. Zi=Ri+jXi，ZL=RL+jXL
I=Us/(Zi+ZL)=Us/(Ri+jXi+RL+jXL)=Us/sqrt{(Ri+RL)²+(Xi+XL)²}
P负载=I²RL=Us²RL/(Ri+RL)²+(Xi+XL)²
Xi+XL=0 XL=-Xi
P负载=I²RL=Us²RL/(Ri+RL)²
Ri=RL时，P负载最⼤