串联电路电流相等，I1=I2，即U1/R1=U2/R2，U1/U2=R1/R2并联电压各支路相等，U1=U2，I1R1=I2R2，I1/I2=R2/R1
串联时: Ⅰ1=U1／R1=Ⅰ2=U2／R2 则 U1/U2=R1/R2并联时：U1= Ⅰ1R1= U2= Ⅰ2R2 则 Ⅰ1/ Ⅰ2=R2/R1
