Peripheral equipment (also called: input and output devices) connects a computer to other things. It gives a computer system more features. Input is anything that goes in and output is anything that goes out. Any device for the computer that the computer can work without is peripheral equipment. This equipment is always separated from the central processing unit (CPU) by a device controller.
Peripheral equipment is necessary for people to interact with a computer system. Some peripheral equipment displays information (such as a computer monitor). Some peripherals, such as touchscreens, work for both input and output.
Peripheral equipment is often labelled I/O device (Input/Output device). I/O devices are connected to a device controller which is connected to the electronics in the computer system. An example of an output device is a set of computer speakers. Computer speakers are plugged into a device controller called an audio device. The device is connected to the rest of the system inside. An example of an input device is a computer mouse. It is connected in the same way as an output device. Most peripherals connect by cable but some connect by Bluetooth radio.
One peripheral device can be connected to many systems.
Sometimes extra memory devices such as a second hard disk can be called peripheral equipment. People who make computer programs call everything except the processor and main memory an I/O device. To an engineer working on the design of a processor, everything except the processor is called an I/O device.
An input device is anything that puts information inside a computer. It is a hardware device that sends information into the CPU. Without any input devices a computer would simply be a display device and not allow users to interact with it, similar to a TV. Below is a listing of different types of computer input devices.
- Computer mouse: The device for moving the cursor or arrow around the screen.
- Digital camera: A digital camera takes pictures to put into the computer. The pictures become information inside the computer.
- Image scanner: Digitizes a document or other two-dimensional object.
- Keyboard: The device for typing characters into the computer.
An output device is anything to which the computer sends signals, for example things that display information from the computer or make sound from the computer.