1) E=2.1 B R1=6 R2=5 R3=3 I3=?
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R13=R1*R3/(R1+R3)=6*3/(6+3)=2
Ro=R13+R2=2+5=7
Io=E/Ro=2.1/7=0.3 A
U13=Io*R13=0.3*2=0.6 B
I3=U13/R3=0.6/3=0.2 A
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2) R1=R2=R3=R=6 r=1 E=10 B U1=?
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R23=R/2=6/2=3
Ro=R23+R1=3+6=9
Io=E/(Ro+r)=10/(9+1)=1 A
U1=Io*R1=1*6=6 B
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4) I1=1 A I2=10 A Rш=0,3 Ом Ra=?
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n=I2/I1=10/1=10
Ra=Rш*(n-1)=0.3*(10-1)=2.7 Ом
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