R R P 2LV2L LC pi e P2 t0+i=0 i=0 t00 2t t=tm时最大 L (0)=U0 ll()=0 C CU 0 (pip,e PIt PiP dt (P-P) 0<t<t,0 i增加,u U (ePi-ep2) ppi L(P2 -P LC 减小,u<0 时u1极小 7s7 (Pe"-P2e"2) t>2tnu衰减加快 dt(P-PD( ) ( ) ( ) ( ) 1 2 1 2 2 1 0 1 2 1 2 2 10 p t p t C p t p t e e L P P U p p e p p e P P C U dt du i C − − − = − − − = − = t=0+ i=0 , t=  i=0 t = tm 时i 最大 0< t < tm i 增加, u L>0 t > tm i 减小, u L <0 t = 2 tm 时 u L 极小 ( ) ( ) 1 2 1 2 2 1 0 p t p t L P e P e P P U dt di u L − − − = = 2 tm u L tm i u L (0)= U0 t > 2 tm u L 衰减加快 t> 0 i>0 t U0 u c ( ) 1 2 2 1 2 1 0 p t p t C P e P e P P U u − − L LC = R LR p 1 ) 2 ( 2 2 1,2 = −  − LC P P 1 1 2 = u L ( )=0