1. INTRODUCTION TO COMPUTER CHAPTER N0 2 INPUT & INPUT & OUTPUT DEVICES OUTPUT DEVICES INSTRUCTOR: ADEEL ANJUM ADEEL ANJUM

2. INPUT DEVICES What do you know about input devices? List out input devices. Input refers to data entered into a computer for processing. Input refers to data entered into a computer for processing. The devices used to feed information into a computer are called input devices. The basic purpose of these devices is to store data. Input is of two type, one data or information and other instruction to manipulate this data to derive the required result The devices used to feed information into a computer are called input devices. The basic purpose of these devices is to store data. Input is of two type, one data or information and other instruction to manipulate this data to derive the required result Examples of input devices keyboard,mouse,scanner,joystick,biometric devices,webcam,microphone,digital camera. Examples of input devices keyboard,mouse,scanner,joystick,biometric devices,webcam,microphone,digital camera. 2

3. KEYBOARD When we press a key of keyboard the letters on that key appears on the monitor and the corresponding ASCII code activated inside the computer memory. When we press a key of keyboard the letters on that key appears on the monitor and the corresponding ASCII code activated inside the computer memory. The keyboard A keyboard is a device that convert letters, number and other characters into electrical signals that can be read by the computer’s processor. The keyboard A keyboard is a device that convert letters, number and other characters into electrical signals that can be read by the computer’s processor. look like a typewriter keyboard to which some special keys have been added. Traditional keyboard have 106 keys for desktop computer.Laptop have 85 keys.PDA have 20 keys. look like a typewriter keyboard to which some special keys have been added. Traditional keyboard have 106 keys for desktop computer.Laptop have 85 keys.PDA have 20 keys. William Austin patent an Americian in 1829 invented first type writer. William Austin patent an Americian in 1829 invented first type writer. The keyboard is divided into following divisions:  ALPHABETIC KEYPAD  NUMBERIC KEYPAD  FUNCTION KEYS  SCREEN NAVIGATION AND EDITING KEYS 3

4.  ALPHABETIC KEYPAD These keys are similar to a standard typewriter and is used to type general information. These keys are similar to a standard typewriter and is used to type general information. FOR EXAMPLE: English alphabets (from A to Z and a to z) FOR EXAMPLE: English alphabets (from A to Z and a to z)  NUMBERIC KEYPAD These keys are used to input numeric data only. These keys are used to input numeric data only. FOR EXAMPLE (0 to 9) FOR EXAMPLE (0 to 9) These keys can also be used as an alternative to the screen navigation and editing keys. These keys can also be used as an alternative to the screen navigation and editing keys.  FUNCTION KEYS These are keys marked as F1 - F12, located normally at the top of the keyboard. These are keys marked as F1 - F12, located normally at the top of the keyboard. These are special keys provided to a programmer which allow him to attach special functions to each key. These are special keys provided to a programmer which allow him to attach special functions to each key. Each of these function keys are also given some special function in different packages. Each of these function keys are also given some special function in different packages. 4

5.  SCREEN NAVIGATION AND EDITING KEYS These keys are provided to move around in the screen. These keys are provided to move around in the screen. May programs use these keys to let the user move around the screen display. May programs use these keys to let the user move around the screen display. In some keyboards these keys are also provided inside the numeric keypad as alternate keys. In some keyboards these keys are also provided inside the numeric keypad as alternate keys. Escape key,Tab key,ctrl,shift,Alt,backspace,enter,caps, Escape key,Tab key,ctrl,shift,Alt,backspace,enter,caps, Num,scroll,End,home,page up,page down.  TOUCH SCREEN A touch screen is a video display screen that has been sensitized to receive input from the touch of a finger. A touch screen is a video display screen that has been sensitized to receive input from the touch of a finger. 5

6. MOUSE It is pointing device. It is pointing device. pointing devices control the position of cursor or pointer on the screen and allows the user to select options displayed on screen. pointing devices control the position of cursor or pointer on the screen and allows the user to select options displayed on screen. The mouse is an input device that usually contains one or two buttons. The mouse is an input device that usually contains one or two buttons. As a user moves the mouse on a flat surface, the mouse controls the cursor movement on the screen. As a user moves the mouse on a flat surface, the mouse controls the cursor movement on the screen. When the user presses one of the buttons, the mouse either marks a place on the screen or makes selection from data or menu on the screen. When the user presses one of the buttons, the mouse either marks a place on the screen or makes selection from data or menu on the screen. A mouse has a sphere on its underside. This rotates as the mouse is moved along a flat surface. A mouse has a sphere on its underside. This rotates as the mouse is moved along a flat surface. The mouse translates the direction and speed of rotation into a digital signal that identifies the position or control, the cursor on the computer. The mouse translates the direction and speed of rotation into a digital signal that identifies the position or control, the cursor on the computer. We have mechanical mouse and optical mouse.mechanical also called wheel mouse and optical mouse use laser beam and special chip. We have mechanical mouse and optical mouse.mechanical also called wheel mouse and optical mouse use laser beam and special chip. 6

7.  SCANNER It is device to translate images of text,drawing,photos,into digital form. It is device to translate images of text,drawing,photos,into digital form. The images can then be processed by a computer displayed on monitor, stored on storage device, or transmitted to another computer. The images can then be processed by a computer displayed on monitor, stored on storage device, or transmitted to another computer.  WEBCAM A video camera attached to a computer to record live moving images that can be posted on website in a real time. A video camera attached to a computer to record live moving images that can be posted on website in a real time. Webcam has become popular with web user. Webcam has become popular with web user.  DIGITAL CAMERA It uses a light sensitive processor chip to capture photographic images in a digital form and store them on a small diskette inserted into camera or flash memory cards It uses a light sensitive processor chip to capture photographic images in a digital form and store them on a small diskette inserted into camera or flash memory cards  SENSORS A sensor is an input device that collects specific data directly A sensor is an input device that collects specific data directly from the environment and transmits it into a computer.sensor can be used to detect all kind of things speed,movement,weight,light,shapes, from the environment and transmits it into a computer.sensor can be used to detect all kind of things speed,movement,weight,light,shapes, images,wind,gas,smoke,light and so on.  BIOMETRIC DEVICES It is human biology input devices.biometric mean science of measuring individual body characteristic.biometric security devices identify a person through a finger prints,hand,eyes or facial characteristic. now day computer with biometric sensor that read finger prints,instead of password. 7