What are Peripheral Devices?

Peripheral devices are those devices that are linked either internally or externally to a computer. These devices are commonly used to transfer data. The most common processes that are carried out in a computer are entering data and displaying processed data. Several devices can be used to receive data and display processed data. The devices used to perform these functions are called peripherals or I/O devices.

Peripherals read information from or write in the memory unit on receiving a command from the CPU. They are considered to be a part of the total computer system. As they require a conversion of signal values, these devices can be referred to as electromechanical and electromagnetic devices. The most common peripherals are a printer, scanner, keyboard, mouse, tape device, microphone, and external modem that are externally connected to the computer.

The following are some of the commonly used peripherals −


The keyboard is the most commonly used input device. It is used to provide commands to the computer. The commands are usually in the form of text. The keyboard consists of many keys such as function keys, numeric keypad, character keys, and various symbols.


The most commonly used output device is the monitor. A cable connects the monitor to the video adapters in the computer’s motherboard. These video adapters convert the electrical signals to the text and images that are displayed. The images on the monitor are made of thousands of pixels. The cursor is the characteristic feature of display devices. It marks the position on the screen where the next character will be inserted.


Printers provide a permanent record of computer data or text on paper. We can classify printers as impact and non-impact printers. Impact printers print characters due to the physical contact of the print head with the paper. In non-impact printers, there is no physical contact.

Magnetic Tape

Magnetic tapes are used in most companies to store data files. Magnetic tapes use a read-write mechanism. The read-write mechanism refers to writing data on or reading data from a magnetic tape. The tapes sequentially store the data manner. In this sequential processing, the computer must begin searching at the beginning and check each record until the desired data is available.

Magnetic tape is the cheapest medium for storage because it can store a large number of binary digits, bytes, or frames on every inch of the tape. The advantages of using magnetic tape include unlimited storage, low cost, high data density, rapid transfer rate, portability, and ease of use.

Magnetic Disk

There is another medium for storing data is magnetic disks. Magnetic disks have high-speed rotational surfaces coated with magnetic material. A read-write mechanism is used to achieve access to write on or read from the magnetic disk. Magnetic disks are generally used for the volume storage of programs and information.

There are some peripheral devices found in computer systems including digital incremental plotters, optical and magnetic readers, analog to digital converters, and several data acquisition equipment.