Computer Graphic Hardware
Graphics
cards/accelerators
What is a graphic's card?
A modern graphics card is a circuit board with memory and a dedicated processor is designed specifically to handle the intense computational requirements of displaying graphics. Most of these graphics processors have special command sets for graphics manipulation built right into the chip.
Graphics cards are known by many names, such as:
- Video cards
- Video boards
- Video display boards
- Graphics boards
- Graphics adapter cards
- Video adapter cards
Why do we need a Graphics Card?
The graphics card plays an essential role in the PC. It takes the digital information that the computer produces and turns it into something human beings can see. On most computers, the graphics card converts digital information to analog information for display on the monitor; on laptops, the data remains digital because laptop displays are already digital.
Three Graphics Card Components
Here are the three basic components of a graphics
card and what they do:
- Memory: The first component that a graphics card needs is memory. The memory holds the color of each pixel. In the simplest case, since each pixel is only black or white, you need just 1 bit to store each pixel's color. Since a byte holds 8 bits, you need (640/8) 80 bytes to store the pixel colors for one line of pixels on the display. You need (480 X 80) 34,800 bytes of memory to hold all of the pixels visible on the display.
-
Computer Interface: The second component a graphics card needs
is a way for the computer to change the graphics card's memory. This is normally
done by connecting the graphics card to the card bus on the motherboard. The
computer can send signals through the bus to alter the memory.
Video Interface: The third component that the graphics card needs is a way to generate the signals for the monitor. The card must generate color signals that drive the cathode ray tube (CRT) electron beam, as well as synchronization signals for horizontal and vertical sync. It sends signals to the monitor for each pixel on each line, and then sends a horizontal sync pulse; it does this repeatedly for all 480 lines, and then sends a vertical sync pulse to the monitor.
The basic parts of a graphics card are computer interface, memory and video interface.
Advantages of Using a Graphics Cards
Though every PC has a video card that sends images from your programs to the
monitor, some of these video cards are also accelerator cards. Simply put,
with an accelerator, images get to, and move about, your monitor more quickly.
Examples of cards:
| ATI ATI's
dual monitor Radeon VE ($99) ¥ Memory: 32MB ¥ Maximum number of colors at maximum resolution: 32-bit ¥ Connectors: DVI-I, VGA, S-Video ¥ Compatible operating systems: Windows 98, Windows 2000, Windows Me |
 |
 |
Matrox Matrox Millennium G550 ($125) ¥ Memory: 32MB |
|
Hercules The Hercules 3D Prophet 4500 ($150) ¥ Memory: 64MB |
 |
 |
Creative Creative Labs' 3D Blaster Annihilator2 Ultra ($500) ¥ Memory: 64MB ¥ Connectors: VGA |
|
GEForce3 GeForce3 ($349) ¥ Memory: 64MB |
|
New Innovations
Digital Graphics
Uploading graphics to the computer
Digital image processors
Scanner/Digital Camera
JLIP program
Demonstrate how to transfer graphics to computer (digital imaging)
Save in any form i.e. gifs, jpeg, tiff