What is a Peripheral Device?

A peripheral device is any auxiliary device that connects to and works with the computer to either put information into it or get information out of it.

Usually, the word peripheral is used to refer to a device external to the computer, like a scanner, but the devices physically located inside the computer are also technically peripherals too.

Peripheral devices often aren't directly involved with a computer's main function, but that doesn't mean they aren't considered necessary components.

For example, a desktop-style computer monitor doesn't technically assist in computing but it is required to use the computer.

Another way to think about peripheral devices is that they don't work as standalone devices. The only way they work is when they're connected to, and controlled by, the computer.

A peripheral device may also be referred to as an external peripheral, integrated peripheral, auxiliary component, or I/O (input/output) device.

Types of Peripheral Devices

Peripheral devices are categorized as either an input device or an output device.

Among these types of hardware are both internal peripheral devices and external peripheral devices, either type of which might include input or output devices.

Internal Peripheral Devices

Common internal peripheral devices you'll find in a computer include an optical disc drive, a video card, and a hard drive.

Network interface cards, USB expansion cards, and other internal devices that might plug in to a PCI Express or other type of port are all types of internal peripherals.

External Peripheral Devices

Common external peripheral devices include devices like a mouse, keyboard, pen tablet, external hard drive, printer, projector, speakers, webcam, flash drive, media card readers, and microphone.

Anything that you can connect to the outside of a computer, that typically doesn't operate on its own, could be referred to as an external peripheral.