(2)由0c,查表得：a=0.218,=0.391 又：lcmax=2A Ico -Colemax =0.436A Icm=aiiemax =0.782A B人07s2x15=i86w P=1m0'c=0.436×18=7.85W 7e= =74.7% P P.=P-P=1.985W R。= Vm=19.292 cml c(2)由θc，查表得： 0 1 α = 0.218, 0.391 α = 又： max 2 ci A = 0 0 max 0.436 cm c I = = α i A 1 1 max 0.782 cm c I = = α i A 0 1 1 1 0.782 15 5.865 2 2 P IV W = =× × = cm cm 0 0.436 18 7.85 P IV W = = cm cc = ×= 0 c 74.7% PP η = = = 0 1.985 PPP W c =−= = 1 19.2 cm e cm c V R I = =Ω