歐姆定律練習題

1:設點源電壓 UV 則 U/(15 + 60) = 0.2 則 U = 15(V)

則點流為1.2A時 總電阻 R= 15/1.2 =12.5

(歐姆)電阻變小,采用並聯 R2*15/(R2 + 15) =12.5

R2 = 75(歐姆)

2.電阻串聯,R1電流與R2電流相等;I = V1/R1 =V2/R2

I = 2 / 4 =0.5 (A)

R2 = (6-2)/I = 4/0.5 = 8(歐姆)