所有电脑的USB都有5V输出，标准输出电流的0.5A, 如果USB divice 需要大过0.5A,当然要买自带电源的。

来源: 于 2022-07-21 09:44:24 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

要还是不要，要看你的 divice 需要的电流。一般的外接 divice 如果·超过0.5A. 都会自带 power supply 。例如外接的硬盘，特别是机械式硬盘。

 

What is the power output from a computer USB port? Most computer USB ports supply 5V of electricity with a maximum current of 0.5A. This amount of current is standard across the majority of computers and means the overall power output will be 2.5 Watts at best. Later USB designs bring that current up to 0.9A.