Input Devices




A keyboard contains keys that allow a user to enter data and instructions into the computer. All computer keyboards have a typing area that includes the letters of the alphabet, numbers, punctuation marks, and other basic keys. Many desktop computer keyboards also have a numeric keypad located on the right side of the keyboard. On notebook and many handheld computers, the keyboard is built into the top of the system unit. A standard computer keyboard is called a QWERTY keyboard because of the layout of its typing area which is similar to that of a typewriter.

Advantages of using keyboards for data input include

It is not necessary to buy additional equipment because most computer systems are normally supplied with keyboards.

Entering data and instructions with keyboards is generally faster than with pointing devices.

Disadvantages of using keyboards for data input include

It takes a lot of time to practice in order to type quickly and accurately.

Typing speeds are still very slow when compared with computer speeds.



MouseA mouse is the most widely used pointing device with a GUI environment on personal computers. A mechanical mouse has a rubber ball on its underside to detect movement of the mouse. An optical mouse uses devices that emit and sense light to detect the mouse’s movement. A cordless mouse (either mechanical or optical) transmits data using wireless technology such as radio waves or infrared light waves.

Advantages of using a mouse include

A mouse is user-friendly for computer beginners.

A mouse is easy and convenient to use with a graphical user interface.

Using a mouse to select items or move to a particular position on the screen is faster than using a keyboard.

Disadvantages of using a mouse include Student Notes

It is not easy and convenient to input text with a mouse.

Issuing commands by using a mouse is slower than by using a keyboard.

A mouse is not accurate enough for drawings that require high precision.

A mouse usually requires a flat surface to operate.

A mouse needs more desk space to operate when compared with a trackball.




A joystick is a pointing device with a vertical lever mounted on a base. The lever usually includes buttons called triggers, which activate certain events when pressed. Joysticks are mainly used for computer games and ultrasound scanners in hospitals.

Advantages of using a joystick include

A joystick allows fast interactions required in most games.

Disadvantages of using a joystick include

It is difficult to use a joystick to select objects accurately on the screen.


Light Pen


A light pen is a pointing device that can detect the presence of light. Light pens are used by health care professionals (such as doctors and dentists) and design work.

Advantages of light pens include

Using a light pen is more direct and precise than using a mouse.

Light pen is also convenient for applications with limited desktop space.

Disadvantage of light pens includes

Light pens normally require a specially designed monitor to work with.




A scanner is a light-sensing input device that converts printed text and graphics into a digital form that can be further processed by the computer. Two popular types of scanners are: A flatbed scanner works like a copy machine except that it creates a file of the document rather than a paper copy. A handheld scanner can be manually passed over the image to be scanned. A portable device you can use to copy an image from paper to your computer.

Hand-held scanners are ideal for capturing small images, such as signatures and logos. A hand-held scanner is smaller, less expensive, and more portable than a flatbed scanner. Scanners are mainly used for image processing, which consists of capturing, storing, analysing, displaying, printing, and manipulating images. Many scanners also include optical character recognition (OCR) software, which can convert an image of text into a text file that can be edited.

Advantages of a scanner include

A scanner with appropriate OCR software can work as an OCR system.

Disadvantages of a scanner include

A scanner is best for two-dimensional objects only, difficult to scan 3-D objects

Scanned images usually take up a lot of storage space.


OCR (optical Character Recognizer)


Most OCR readers include a small optical scanner for reading characters and sophisticated OCR software for analysing what is read.

Advantages of OCR readers include

Written data and printed data can be read at the same time.

Hard copies of documents can be read directly into a computer without retyping.

The characters converted can later be edited by word processing software.

Disadvantages of OCR readers include

OCR readers often do not work well with handwritten characters or those in unusual fonts.


Magnetic Ink Character Reader (MICR)


A magnetic ink character recognition (MICR) reader can read text printed with magnetized ink. Magnetic ink character recognition is used most exclusively by the banking industry for processing checks. The characters represent the check number, the bank number, and the account number of customers.

Advantages of MICR readers include

MICR is difficult to forge.

Documents can still be read when folded or written on.

Disadvantages of MICR readers include

 MICR readers and encoders are very expensive

 The system can only accept a few different character sets.


Touch Screen

Tuch ScreenA touch screen is an input/output touch-sensitive display. Touch screens are often used for information kiosks located in department stores, hotels, airports, and museums. Touch screens are also used for ATM machines to allow easy access of bank accounts.

Advantages of a touch screen include

No extra peripherals are needed except the monitor.

A touch screen allows easy access to commands, which are usually identified by words or symbols on the screen.

Disadvantages of a touch screen include

Touch screens are not suitable for inputting a large amount of data because they require a lot of arm movements.

Only items already on the screen can be selected.


Bar code reader

Bar Code Reader

A bar code reader uses laser beams to read bar codes. A bar code reader reads a bar code by using light patterns that pass through the bar code lines. Bar code readers are widely used in a POS e.g. supermarkets, department stores, libraries, etc.

Advantages of using bar codes and bar code readers include

The process of data entry is fast and accurate.

Bar codes can be printed by normal printing methods.

No need to write down or key in the name of the item or its actual price.

Disadvantages of using bar codes and bar code readers include

A bar code reader may misread a bar code if there is any dirt or mark on the code.

Only numbers can be coded.












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