There are three 470ohm resistors are connected in series with a 48V source.What is the minimum power

题目

There are three 470ohm resistors are connected in series with a 48V source.What is the minimum power rating of the resistors?正确答案是0.543W,谁能解释一下为何3个同样的电阻还有最小值可言?如何计算出这个结果的,

答案

晕,你对电阻的参数有一个误解.
电阻的参数除了阻值外,还有一个参数,表征它能够通过的最大电流.通常是用功率表示的,中文叫做额定功率,英文叫做power rating.
这道题是问你这三个电阻的额定功率最小可以是多少（再小就会被烧掉）.
I=48/(3*470)
P=IIR,这个就是每个电阻的实际耗散功率,power rating必须大于这个功率,否则电阻就会烧.