人教版高中英语选修计算机英语WhatAreInputDevices.ppt

Input Popular input devices keyboard mouse microphone scanner 101 to 105 keys Input devices Desk Computer Keyboards Input devices Some Extra Keys like arrow key, function keys etc Enter Key use in issuing command Num-Lock and Insert Key toggle between two states Special Keys (Shift, Ctrl and Alt) use with other keys to increase the function of a keyboard Pointing devices Features Normally with two buttons and a small wheel Moved under user’s palm Pointing devices Mechanical Mouse Has a ball on its underside A circuit converts movement into electrical signals Optical Mouse Emits light and senses Doesn’t require clean More expensive Pointing devices Trackball Rotate the ball with a finger Requires frequent cleaning An upside-down mechanical mouse Touchpad A small, flat pointing device Move fingertip across the pad Works like mouse buttons Pointing devices Joystick Used in computer games The lever allows movement in different ways Buttons activate actions Wheel Control vehicle in driving simulation software include foot pedals for acceleration and braking actions Pointing devices Touch Screen Without keyboard or mouse Mainly use pressure-sentive computer screen Light Pen Can sense light Work with a standard monitor It’s very convenient Voice Input is the process of entering data by speaking into a microphone. It is part of a kind of input called audio input. Input devices What is the voice recognition? Input devices Voice Recognition, also called speech recognition, is the computer’s ability to tell the difference between spoken words. In the past, it was designed for the busy and the disabled. Today, it mainly gives people convenience to input. A digital camera lets users take pictures and store the photographed images digitally, rather than on traditional film. Input devices It usually lets users look at, and sometimes edit, images when they are in the camera. Input devices An optical scanner Can se