二.换路定律(开闭定则) ()=a= 0 55+cJ(5)5 i (0)+ Co-i(s)dE c q=Cuc a(0)=4(0)+lois)ds 1=0时刻42()=2(0)+m0(505 0 q (0+)=9(0)+i(3)l 当〔(2)为有限值时 0 Lc(0+)=Lc(0) mi(0/→0(9(0)=g(0)电荷守恒 结论换路瞬间,若电容电流保持为有限值, 则电容电压(电荷)换路前后保持不变。[二.换路定律（开闭定则） ( )d 1 ( ) − = t C i C u t   ( )d 1 ( )d 1 0 0   − − = + − t i C i C ( )d 1 (0 ) 0 = + − − t C i C u q =C uC t = 0+时刻 ( )d 1 (0 ) (0 ) 0 0 + − = + + − i C uC uC ( ) (0 ) ( )d 0 − = + − t q t q i 当i()为有限值时 i uc C + - q (0+ ) = q (0- ) uC (0+ ) = uC (0- ) 电荷守恒 结论 换路瞬间，若电容电流保持为有限值， 则电容电压（电荷）换路前后保持不变。 1.  + − = +   + − 0 0 q(0 ) q(0 ) i( )d  + −   → 0 0 i( )d 0