USB hubs increase the number of USB devices that can connect to a computer without having to add additional hardware. Additionally, USB hubs can be useful with devices like laptops that can’t physically add more USB ports. The difference between powered and non-powered USB hubs is that the former draws its power from an electrical outlet while the latter draws its power from the computer connection.

USB

USB is the most commonly used external peripheral device connection standard for computers and other computer-like devices. Computers use USB ports to interface with devices like mice, keyboards, external hard drives, printers, scanners, gamepads, network adapters, flash drives, smartphones and cameras. The USB standard is backwards and forwards compatible, which means new devices and computers can take advantage of faster standards without sacrificing compatibility with older standards. In addition to data, USB is also a power source for devices which don’t always use a data connection. For example, a cell phone connected to a computer with a USB cable can both interface with the computer and charge its battery. A cell phone that’s connected to a wall outlet charger by USB is only using the connection as a power source.

Hubs

USB hubs are devices that connect to a computer’s existing (native) USB port to add additional ports to increase the number of devices that can be connected to the computer. However, there’s a catch when using USB hubs: all the devices have to share bandwidth and a power supply from the computer’s native USB port. The bandwidth and power from the computer’s port is the same no matter how many devices are connected. Not all USB devices are created equal: some require more power than others, and some less. USB hubs work fine with low-powered devices like mice and keyboards, but they may not be able to operate high-powered devices like webcams and flash drives. Devices may fail to work or produce error messages if the hub doesn’t have sufficient power – which is where powered USB Hubs come into play.

Powered

Powered, or active, USB hubs use an external power source, typically through a wall outlet, to bring each hub port to the same energy level as an on-system port. While active USB hubs do not need to divide power consumption across all connected devices, the hub still splits data bandwidth across all connected devices, which is something that simply cannot be avoided when using a hub. Using a powered USB hub is especially useful when using laptops, which have a limited amount of power to go around, but are the preferred type of hub for ANY type of computer/device. Although less convenient than an unpowered hub due to the need to plug it into an outlet, devices connected to powered hubs function and perform better in every way, as well as produce less errors overall, than their unpowered counterparts.

Unpowered

Non-powered, or passive, USB hubs do not have an external power source and only pull power from the computer’s USB port. Unpowered hubs typically have compatibility issues with devices that need more power to operate than the hub can provide. For example, a USB flash drive might work perfectly fine with the computer’s native USB port or an active hub, but it may not power on when connected to a passive hub – the same would hold true for a USB connected hard drive, or monitor. The USB 3.0 standard improves power management capabilities over the previous versions and may be able to use higher power devices that hubs running older standards can’t – but the safest bet is to always use an active hub where possible.