XL=40x1=j40
i(t)=60cos40t x 10/(10+20+j40)
=60cos40t x 1/5∠53o
=12cos(40t-53o)
46.有一電路如【圖 17】,i(t)=? (A) 12sin(40t − 5..-阿摩線上測驗