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Unit 5: Computer Hardware

5.1 Input and Output Devices
Notes
Input Devices are used to input data, information and instructions into the RAM. Common input
devices include Keyboard, Mouse, Joystick, Trackball, Touch Screen, Light Pen, Digitizer, Scanner,
Digital Camera, MICR (Magnetic Ink Character Recognition), OMR (Optical Mark Reader), OCR
(Optical Character Reader), Bar Code Reader and Voice-Input Device. Input Devices are classified
into the following two types :
(a) Basic Input Devices
(b) Special Input Devices
Output devices are hardware components, which are used to display or print the processed
information. Common output devices include Monitor, Printer, Plotter, Speaker and COM (Computer
Output Microfilm) device. Output devices are also classified into the following two types:
(a) Basic Output Devices
(b) Special Output Devices
In this unit, we are discussing below the structure, working and uses of these basic and special
input/ output devices.

5.1.1 Basic Input Devices

The input devices, which have become now essential to operate a today’s PC are called Basic Input
Devices. These devices are always required for basic input operations. These devices include
Keyboard, Mouse and Microphone. Today every PC has these devices as shown in Figure 5.1. Let
us discuss them.

Keyboard
Keyboard is the main basic input device of a computer. It is the most commonly used means by
which you can communicate with a computer. It consists of various types of keys that are operated
through pressure applied by finger. When any key is pressed, an electronic signal is produced. A
keyboard encoder that sends a binary code corresponding to the key pressed detects this signal.

Figure 5.1: A Personal Computer Having Basic Input Devices

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