# Tutorial 11

1. Describe the three elements that make up one dot of color.

One dot of color is made up of three smaller dots: one red, one green, and one blue.

2. What is the advantage of interlacing? Is it worth doing?

Interlacing is a way of arranging a video display so that the CRT sweeps all the odd-numbered rows and then all the even-numbered rows (or vice versa). The intention of interlacing is to reduce the flicker on the screen by increasing the refresh rate (in other words, scanning the screen twice as often). An interlaced monitor can be well-suited for stand-alone servers or computers that run for long hours unattended. It might be a good choice when there will be little interaction by an operator or when cost is a primary factor. Interlacing should be avoided for normal use, because it can lead to eyestrain and headaches.

3. Should a monitor be turned on and off, or left on all day?

The most basic form of power management is to turn off the monitor, using the power switch. At the same time, the CRT is the most expensive component of a monitor and can be damaged when it is turned on and off too frequently. Because these two concepts contradict each other, there is no single correct answer. You will have to make a decision based on the customer's individual circumstances.

4. What is the "standard" type of video card used with today's computers?

Some variation of the SVGA video card is used on most computers sold today.

5. What is the formula for calculating the required memory for a monitor/video card combination?

The formula is: video memory requirement = horizontal pixels x vertical pixels x color depth.

6. What does CRT stand for?

It stands for cathode-ray tube.

7. What are HRR and VRR?

The number of times per second an electron beam sweeps is called the refresh rate. The speed at which the electron beam completes one horizontal trace is known as the horizontal refresh rate (HRR). The time taken by the monitor to complete all horizontal traces and return to the top of the screen is the vertical refresh rate (VRR).

8. Define resolution.

Resolution is the measurement of image detail produced by a monitor or printer. Monitor resolution is expressed as the number of horizontal pixels by the number of vertical pixels.

9. What is bandwidth?

With computer monitors, bandwidth is the maximum number of times per second an electron gun can be turned on and off. Bandwidth is measured in megahertz (MHz-millions of cycles per second). A typical value for a high-resolution, 17-inch color monitor would be around 100 MHz.

10. Why is it dangerous to open the monitor's cover?

The CRT part of a monitor acts like a large capacitor and is capable of holding a very large charge (30,000 volts).

11. Name four common sources of video problems.

The video-signal cable, video controller card, video-driver software, and the monitor are the four primary sources of video problems.

12. Explain one similarity and one difference between VRAM and WRAM.

Both offer dual port reads and writes, but WRAM is faster and less expensive.

13. What is a raster?

Video data is displayed on the monitor by sweeping the electron gun(s) in a series of horizontal lines or traces across the display. The line created by each sweep is called a raster. The number of rasters is used to describe the vertical resolution of a monitor.

14. What type of connector is used for an SVGA monitor?

The PGA, VGA, and SVGA monitor each use a 15-pin, three-row, female DB connector.