Introduction to Computers Chapter 4A PDF

McGraw-Hill Technology Copyright © 2006 by The McGraw-Hill Companies, Inc. All McGraw-Hill Technology Education Copyright © 2006 by The McGraw-Hill Companies, Inc. All  Chapter 4A Video and Sound McGraw-Hill Technology Copyright © 2006 by The McGraw-Hil...

McGraw-Hill Technology Copyright © 2006 by The McGraw-Hill Companies, Inc. All McGraw-Hill Technology Education Copyright © 2006 by The McGraw-Hill Companies, Inc. All  Chapter 4A Video and Sound McGraw-Hill Technology Copyright © 2006 by The McGraw-Hill Companies, Inc. All  Monitors Most common output device Connects to the video card Categorized by color output – Monochrome One color with black background – Grayscale Varying degrees of gray – Color Display 4 to 16 million colors 4A-3  Monitors Cathode Ray Tube (CRT) – Most common type of monitor – Electrons fired from the back – Electrons excite phosphor to glow – Phosphor is arranged in dots called pixels – Dot mask ensures proper pixel is lit  Monitors CRT color – Phosphor dots arranged in triads – Red, green, and blue dots – Three colors blend to make colors – Varying the intensity creates new colors  Monitors CRT drawbacks – Very large – Very heavy – Use a lot of electricity  Monitors Liquid Crystal Display (LCD) – Commonly found on laptops – Desktop versions exist – Solve the problems of CRT – Fluorescent lights provide illumination  Monitors Passive matrix LCD – Pixels arranged in a grid – Pixels are activated indirectly Row and column are activated – Animation can be blurry  Monitors Active matrix LCD – Each pixel is activated directly – Pixels have 4 transistors One each for red, green, blue One for opaqueness – Transistors arranged in a thin film – Animation is crisp and clean  Monitors Drawbacks to LCD – More expensive than CRT – Must sit directly in front of screen – Can be more fragile than CRT  Monitors Paper-white displays – High contrast between fore and background Electro-luminescent displays (ELD) – Similar to LCD – Uses phosphor to produce light Plasma monitor – Gas is excited to produce light Monitors and Video Cards Monitors impacts user effectiveness Monitors should have – Crisp text – Clear graphics – Adjustable controls – Clear edges Monitors and Video Cards Size of monitor – Measured in inches – Measured diagonally – Actual size Distance from corner to corner – Viewable size Useable portion of the screen Monitors and Video Cards Resolution – Number of pixels on the screen – Higher number creates sharper images – Higher number creates smaller images Monitors and Video Cards Refresh rate – Number of time the screen is redrawn – Modern equipment sets this automatically – Improper settings can cause eyestrain Monitors and Video Cards Dot pitch – Distance between the same color dots – Ranges between.15 mm and.40 mm – Smaller creates a finer picture – Should be less than.22  Video Cards Device between the CPU and monitor Better cards result in better output Removes burden of drawing from CPU Have their own processor and RAM Modern cards have up to 512 MB RAM Capable of rendering 3D images Ergonomics and Monitors Eyestrain – Fatigue of the eyes – Steps to avoid Choose a good monitor Place the monitor 2 – 3 feet away Center of screen below eye level Avoid reflected light Ergonomics and Monitors Electronic magnetic fields (EMF) – Generated by all electronic devices – EMF may be detrimental to health – Steps to avoid Keep the computer at arms length Take frequent breaks Use an LCD monitor  Data Projectors Replaced overhead and slide projectors Project image onto wall or screen LCD projectors – Most common type of projector – Small LCD screen – Very bright light – Require a darkened room  Data Projectors Digital Light Projectors – A series of mirrors control the display – May be used in a lighted room  Sound Systems Integral part of the computer experience Capable of recording and playback  Sound Systems Sound card – Device between the CPU and speakers – Converts digital sounds to analog – Can be connected to several devices – Modern cards support Dolby Surround Sound  Sound Systems Headphones and headsets – Replacement for speakers and microphones – Offer privacy – Does not annoy other people – Outside noise is not a factor – Headsets have speakers and a microphone  Chapter 4A End of Chapter McGraw-Hill Technology Copyright © 2006 by The McGraw-Hill Companies, Inc. All