Given so many devices now power themselves using a USB connection, it’s important to know how much power the USB port on your laptop can supply. If a device tries to draw more power than the port can supply, you risk killing the port—or even starting an electrical fire
Not all USB ports are created equal. Your machine might have a mix of USB 2.0 and USB 3.0 connections, each of which might have different outputs. Knowing a USB plug’s power output also helps to determine if there are any problems with your ports. For example, if a port is not charging gadgets as quickly as normal, you might discover its power supply is not as high as it should be.
Thankfully, it’s easy to measure a USB port’s power output.
How to Check the Power Output of a USB Port
To check the power output of a USB port on Windows, download the free USBDeview. It’s a portable app, so no installation necessary.
Once you fire up the app for the first time, you will see a complete list of all the USB devices that you have ever used, as well as a list of your USB ports. The ports which are currently active on your machine are highlighted using a green checkbox.
To see the details of a USB port, double-click on its name. You will see all the information about the port, including when it was last used, whether it is safe to unplug any currently-connected device, and a whole lot more.
You need to locate the Power field. It will show you how many milliamperes the port can supply.
If you would like to learn about electrical safety, we covered the topic in more detail when we looked at the safety of Kodi boxes.