P P/ 当Um==UC时 Pmn≈0.2m=0.2xlUc i PI/2 2 RL Uc>U O om/occ 0.641 2 ∴m>0.2×1am =0.2×8=1.6W 2 R L Pu >P CM Cm ∴P>16WL CC Cm Lm R U P P 2 2 1  0.2 = 0.2 当 Uom UCC 时  2 = UCC  Uom 0.2 8 1.6W 2 1 0.2 2    =  = L o m Cm R U P  PCM  PCm  PCM  1.6W Uom/UCC 0.64 1 PL/2 PE/2 PC P O