How to Increase USB Power Output

by Jeff GrundyUpdated September 28, 2017
Jupiterimages/ Images

Items you will need

  • Powered USB hub

  • USB cable

When it comes to USB devices, power requirements for them vary a bit. Although designed to produce 5 volts, many USB headers on the motherboard often produce only 4.75 volts – especially the USB ports on the front of many PCs. This can be the result of many reasons, but poor case wiring is usually the culprit. USB flash drives or mice usually function OK with little less power, but larger devices such as full-sized external hard drives and optical drives may not function at all. If you have underpowered front panel USB ports, adding a powered hub can help.

Disconnect all USB peripheral devices. This includes all your flash drives, external drives, Web cams, etc. Do not disconnect a USB keyboard or mouse without first turning off the PC. If you connected a USB keyboard or mouse to the front panel ports, shut down the computer and transfer the keyboard and mouse to USB ports on the rear of the computer.

Connect the AC adapter to the powered hub. Plug the electrical plug for the adapter into an available electrical socket. Plug the small end of the USB cable into the hub. Plug the larger, flat end of the cable into one of the front panel USB ports on your computer. Wait a few seconds for Windows to detect the hub and configure it for use on your PC.

Connect the USB peripheral devices to the empty ports on the hub one at a time. Wait for Windows to detect and configure each device before connecting another one. The voltage output from the hub should remain steady at 5 volts and adequately power your USB devices.


To ensure larger USB devices receive adequate power from the hub, connect larger external hard drives or optical drives to the ports closest to the AC adapter connection. Although not a common issue, some hubs might deliver slightly less power to the ports farthest from the AC adapter plug.


Photo Credits

  • Jupiterimages/ Images

About the Author

Jeff Grundy has been writing computer-related articles and tutorials since 1995. Since that time, Grundy has written many guides to using various applications that are published on numerous how-to and tutorial sites. Born and raised in South Georgia, Grundy holds a Master of Science degree in mathematics from the Georgia Institute of Technology.

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