初始值uc(0＋)＝uc(0－)＝0，稳态值uc(无穷)＝120V，时间常数T＝RC＝0.0003s，即得uc＝120(1－e指数(－10000t/3))V，ic＝Cduc/dt，uR＝(180ic＋uc)/120＝…
uC(t)=120(1-e-33333t)V, uR(t)= 120-48e-33333t V.
