Monitor and Video Display Adapter
|What is it?||What are the Myths||How does it work?||Types||For the advanced user|
The monitor is primarily an output device. It converts electronic signals from the computer into a visual display that is the result of processing information. It can be thought of as a high resolution TV set. The monitor can also determine if the display will be color, black and white, or include graphical objects (pictures). The monitor displays text and images (pictures) converted to output from the video adapter. The video adapter is an expansion card that plugs into the motherboard. The adapter changes the instructions from the central processing unit (CPU) into a way that the monitor can understand it.
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Electromagnetic radiation if a by product of most home appliances such as microwaves, TVs, radios, and computer monitors. Today's computers are required to be MPRII compliant. Which means within an acceptable level of EMR (electromagnetic radiation). Be sure and look for the label MPR II reliant on the specifications for your computer.
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How Does it Produce an Image?
Within the monitor there are red, green, and blue electron guns. Each one shoots out a stream of electrons which all come together to form pixels on the screen. The higher the intensity (red, blue, or green) that is beamed from each of the guns results in the color of the pixel. The guns begins firing in the upper-left corner of the screen and moves quickly across each line of the screen to paint the image that you see. When the gun reaches the bottom right hand corner of the screen, it goes back to the top upper-left hand corner to start all over again.
Monitors have some features that are similar to a television set. There are controls that allow for brightness and contrast, and also the ability to turn the monitor on and off even while the computer is running. Other features of a good monitor would be a non-interlaced monitor that reduces screen flicker and is easier on your eyes. An interlaced monitor means that the electron gun goes across on all even numbered lines on one pass and then scans the odd number of lines on the next pass. The interlaced monitor creates a screen flicker at higher resolutions which tends to be harder on your eyes. If possible buy a non-interlaced monitor.
The size of the monitor is determined by measuring diagonally across the screen. Most monitors are 14" and 15". Be sure and look for the words" actual viewing size "on the specifications when buying a monitor to determine how large the viewing area is.. Also some computers and monitors display the screen image within a frame or border on the screen and the actual viewing area is not what you think it is. The larger the monitor display, the more information that can be displayed. One drawback is the it costs more.
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Today, most systems are sold with a display adapter that connects to a PCI "local bus", supports some Windows accelerator, and provides SVGA resolutions. The "local bus" means that the CPU can send data to the card at high speed. The video display adapter is also called the video card or graphics card. It is an expansion card that creates a circuit pathway so that data can travel from the main board to the monitor.
Elements of the Video Display Adapter:
Resolution refers to the number of dots on the screen or pixels. . It is expressed as a pair of numbers that give the number of dots on a line (horizontal) and the number of lines (vertical). Four resolutions commonly used today.
The smaller the pixels, the clearer and sharper the picture appears on the monitor. Most monitors come with a .28 dot pitch. This is the standard for monitors. Do not buy a monitor if the dot pitch is more than .28. The smaller the dot pitch the better the monitor.
Memory on the video adapter limits the number of colors that can be display at each resolution. If you want to do really high quality photography you need at least 1MB of memory. Multimedia applications with high resolution graphics need at least 2 MB of memory.
The Refresh Rate determines the speed that the display uses to paint the dots on the screen. The refresh rate requirement of a typical monitor is 70Hz. Simply speaking, refresh rate relates to the number of times a screen is redrawn. In many of the popular Internet browsers you will notice a refresh option or reload. This tells the computer to redraw the screen.
With the invention of the graphics accelerator chip on the video card, the display adapter can draw lines and boxes, scroll text, rotate graphics, make background fills, and also use and manage a mouse pointer, and other pointing devices. Application programs can now send requests and with the help of a Windows Driver routine, the adapter can calculate the bits without the help of the CPU, making the procedure faster.
For the more advanced user click here to learn how to maintain your Monitor.
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