Every USB device uses power (50-500mA) over the USB root hub - how much does it really need?
USB devices use their cabling for Datatransfer as well as their source of electric power. Some devices even use their USB port for reloading their battery / accu.
So how much does it really consume? This question is not only for the green guys between us, a overloaded port can be deactivated by your computer or not enough power consumption might lead to a not recognisable device.
If you have trouble with a USB device, which continually "disappears" or seems not to be installed correctly, this is one possible point to look for.
The specification says, the power consumption must not be lower than 50mA, but may not exceed 500mA.
Where do I find it?
In Windows, open your device manager and open the / all USB-Root-Hubs under "USB-Controller". Check the "Power" Tab for devices and power consumption. Possibly you just need to use another USB-Port.
About the Author
Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience, including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform.