设电阻R1,R2,R3,...,Rn总电阻R1/R=1/R1+1/R2+1/R3+...+1/Rn假设Rm为最小电阻则1/R=1/R1+1/R2+1/R3+...+1/Rn>1/Rm即 R<Rm1/R=1/R1+1/R2+1/R3+...+1/Rn<=1/Rm+1/Rm+1/Rm+...+1/Rm=n/RmR>Rm/n即 Rm/n<R<Rm综合即 小于最小电阻,且接近最小电阻。