1、 qq:2355394557 qq:2355394557 100 2 . 1 2015 ( 5/7) R E r P I P0 I1 I2 R1 R2 A 12 E II r B 12 E II r C 1 2 R r rR D 1 2 R r rR B 2. )QQ QQ 1 QQ ( QQ )( ) P O I 1I 2I P 0R E r S A qq:2355394557 qq:2355394557 r U C B 200 W W Pt B 3. U I r A UI I 2 r B UI +I 2 r C I 2 r D % 100 U Ir AC 4 R1R2 q ( )
2、A B R1 R2 C D BD Q=I 2 rt=Iqr R1R2 A Q=I 2 Rt=IqR=Uq R1 R2 B q C D qq:2355394557 qq:2355394557 5.(2015 ) PE PR Pr I a b c A b PR I B a C A B C PA=PB+PC D M N 1 2, 1 4 CD 6. ( 1 ) ( ) A. B. C. D. A P U 2 R A a M O b c A B C P (W) N I (A) 23 qq:2355394557 qq:2355394557 7. 2 S R0 R R0 R S R0 ( ) A.
3、 B. C. D. B S R0 R0 U 2 P B 8. A B A L d B 2L 2d ( ) A.QA QB QA QB C.QA QB QA QB B 1 12 E=6V R1 R2=R3 1 K 2 K qq:2355394557 qq:2355394557 3 K R1 2 (12 ) R1 R2 R1 P1=6W 1 2 3 1 P=U 2 /R P1R1= P2R2 P2=9W P= P1+P2=6W+9W=15W 3 2 P=I 2 R R1 I1= 1 1 R P = 2 /2A; qq:2355394557 qq:2355394557 7 I/A U/V 1
4、2 2 5 10 10 O 20 R2 I2= 2 2 R P =3 2 /4A; I= I1+I2= 2 /2A +3 2 /4A =5 2 /4A 3 Pr= I 2 r=(5 2 2 3 P =EI P = Pr+P E=10.2V 4 3 14 I II 1 2 I II 3 I II 2 I I=5A I= r R E R1= I E -r1 3 II 6A I= r R E R2= I E -r2= 12 10 3 3 I II U1=20/7V U2=5V I P1= I1U1 qq:2355394557 qq:2355394557 II P2= I2U2 4 4. a E=12V r R1 R2 R3 1 C D 2 C D 3 a a b E CD CD CD r 4 C D 1 C D I1= r R R E 2 1 =1A UV=I1R2 2 C D R2 R3 R= 3 2 3 2 R R R R =2 qq:2355394557 qq:2355394557 I2= r R R E 1 =1.5A I2R=IR3, R3 I=1A 1A
