Input and Output Devices of a Computer

Input and Output devices are two of major components of a computer system. Input devices are those hardwares that are responsible for data input, into the computer system. They make it possible for users to key-in instructions and directives for a particular task. While output devices are those hardwares that are responsible for giving out a visual display of processed data (usually called information). An output can either be in softcopy or in hardcopy, depending on what is required by the user.

Input Devices of a Computer

• 1. Keyboard - This is one of the major input devices which is used to input words, commands in form of letters, figures, symbols etc. The keyboard is divided into five (5) main parts which are:
• (i) Alphanumeric keypad - the area that contains letters.
• (ii) Numeric keypad - the area of the keyboard that contains figures.
• (iii) Special keys - these keys include the Shift, Caps Lock, Enter, Num Lock, Space bar, Tab, and Print Screen which are used for special purposes.
• (iv) Control keys - these are keys used to nagivation and control, they include the Home key, End key, Insert key, Delete key, Page-Up key, Page-Down, Control (Ctrl), Alternate (Alt), Escape (Esc), Arrow-left key, Arrow-right key, Arrow-up key and Arrow-down key.
• (v) The function keys - there are twelve (12) function keys in the keyboard (f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11 and f12) which are used to perform specific functions and other purposes.

• 2. Mouse - Mouse is computer pointing device that is used to control the position and navigation of the cursor in a computer display screen. The mouse has two buttons, right and left which are used different purposes in the computer. Modern mouse also comes with a scroll ball in-between its click buttons (this is used to scroll a page up and down). The mouse can be used to open a file or folder by double clicking, it can also be used to view properties of a file by right clicking and going down to click on the property section. Mouse can do a lot of things in a computer system, but it can't be used for typing.

• 3. Scanner - Scanner is an input device that is used to convert hardcopy of files or documents into digital form that can be seen and displayed in a computer system monitor.

• 4. Joystick - A joystick is an input device that is used to control the position and movement of the pointer in a computer system. There are different kinds of joystick, those used in game houses, those used in controlling aircrafts by the pilot and lots more. The joystick also has similar function to a mouse in a computer system.

• 5. Light Pen - A light pen is light sensitive input device that can be used to draw lines, shapes, images and also move over them in a monitor of a computer system.

• 6. Microphone - This is used to convert sound into an electrical signal that can be stored in a computer system for various uses. This input device is used by also all computer devices either for the purpose of recording sounds which might be commands or setting up voice recognition authentication.

• 7. Barcode Readers - This is a type of scanner that reads barcodes by passing a sensitive light across the barcodes. Barcode readers are usually used to verify the authenticity of information in a product.

• 8. Digitizer - A Digitizer is an input device that is capable of converting analog signals into digital signals that can be read by the computer device. An example can be a graphics tablet that is used to draw images using your hand or sensitive pen.

• 9. Magnetic Ink Character Reader (MICR) - This is a computer input device that allows a computer to read and verify character legitimacy of documents. MICR is used in banks and other organizations. The process of reading a document with MICR is called Magnetic Ink Character Recognition.

• 10. Optical Character Reader (OCR) - This is an input device that is used in the conversion of images and text into an encoded file (images and texts). The process of scanning images and text with OCR is called Optical Character Recognition.

• 11. Optical Mark Reader (OMR) - This is another input device that is similar to OCR. It is used to read pen and pencil marks from paper documents. The process of reading pen and pencil marks with OMR is called Optical Mark Recognition. OMR is used in universities and colleges for marking student's answer sheets.

Output Devices of a Computer

• 1. Monitor - This is an output device that displays information in form of images or text format which are usually in tiny dots called pixels. Another name for monitor is Visual Display Unit (VDU). There different types of monitors. Some of the main types of monitors includes the following:
• (i) Cathode Ray Tube (CRT) Monitors - A CRT monitor is a type of traditional monitor that uses vacuum tubes. It is an analog computer display screen that shows images and text.

• (ii) Flat Panel Display (FPD) Monitors - This is a type of electronic display monitor that is light weight, has less volume and power requirements than that of the Cathode Ray Tube monitor. FPD monitor enables people to see its content (text, images, videos etc) clearly from a distance without getting too close to it.

• (iii) Touch Screen Monitors - These are monitors that are sensitive to touch, which can easily be operated by the touch of the someone's thumbs. Touch screen monitors can be seen in android phones, tablets, and also some laptops and televisions.

• (iv) Liquid Crystal Display (LCD) Monitors - This monitor is classified under Flat Panel Display (FPD) device, but it uses a light modulating or liquid crystal properties to show high-definition images and videos.

• (v) OLED Monitors - OLED which stands for organic light emitting diode monitor is a type of computer monitor that is associated with the use of organic light emitting diode to offer quality colours on screen, high contrasts, better viewing angles with low energy consumption and fast response.

• (vi) Plasma Screen Monitors - This is also classified under Flat Panel Display (FPD) device. It is made up of tiny bit of plasma, more or like a tiny neon light which is responsible for showing each pixel in quality format. Examples of plasma screen monitors can your Plasma TV at home, or cinema TV screen in entertainment buildings.

• (vii) Thin Film Transistor (TFT) Monitors - TFT is a computer display monitor that is made with thin film transistor. It is classified under LCD (Liquid Crystal Display) and these types of monitors can readily be found in laptops, notepad and notebooks.

• (viii) Digital Light Processing (DLP) Monitors - These type of computer monitors are created with a video technology made by Texas instrument which is usually used in projection of data content. DLP is used in schools and organizations for project presentations and other informative seminars.

• 2. Printer - A printer can be defined as an output device that produces hardcopy documents or files from softcopies. It takes data stored in a computer system and prints them out into a hardcopy document. There are major categories of printer we have today, we are the 2D and 3D printers.
  2D Printer
  3D Printer
  But we also have different types of printers, which includes the following:
• (i) Inkjet Printer - This is a type of printer that uses ink to create a hardcopy of document and files by putting inks onto a paper properly describing the softcopy it is printing.

• (ii) Laser Printer - A Laser kind of printer is a computer output peripheral device that uses laser to form good quality hardcopy documents. It is called an electrostatic method of digital printing.

• (iii) Thermal Printer - This printer uses heated pins in which a paper (thermochromic coated material or thermal material) is being passed through, to produce an exact replica of the softcopy document in a hardcopy form.

• (iv) Plotter Printer - A plotter printer is computer output peripheral device that is used to print vector graphics. It is a printer that can be used to create drawings and lines using pen other methods in some applications.

• (v) Multifunction Printer - This type of printer can be defined as a printer that can perform multiple printing functions such as copying, scanning and printing documents of different paper sizes (A2, A4, A5 etc). These types of printers are expensive, but serves very well for businesses that requires high work efficiency.