求各电路的V、I、R

求各电路的V、I、R
求各电路的V、I、R

求各电路的V、I、R
 流过10R电阻的电流：Iab = 5V / 10R = 0.5A.
B点、C点之间的电阻Rbc等于20R并联30R ,Rbc = 20 * 30 / (20 + 30) = 12 (R);
所以,Vbc = Rbc *  Iab = 12 * 0.5 = 6 （V); 流过20R电阻的电流是：Vbc / 20R = 6V / 20R = 0.3A;
流过30R电阻的电流是：Vbc / 30R = 6V / 30R = 0.2A;
总电源电压Vac = Vab + Vbc = 5 + 6 = 11（V）；
总电流：I1 = Iab = 0.5A；总电阻：Rac = Rab + Rbc = 10 + 12 = 22 （R）.