They are actually different things - the crt or display is the image producing device (the cathode ray tube (CRT)), and the monitor is the box containing the controls and support circuitry to the display. The monitor contains the buttons, yoke, connectors for electric power and to connect to the video card in your PC.

The image at the right shows you the monitor (the case) and the CRT (the picture screen). The CRT is a large vacuum tube filled with some type of gas that can be activated to make images appear on the CRT. The monitor controls can be used to adjust the contrast, brightness, image alignment, etc.

To a user who looks at the CRT, the most important things are generally, size of the display and the quality of the images projected on the CRT.

The size of CRT viewing area varies, usually from about 13 inches up to 21 inches for most computers (I feel a 17 inch screen is perfect.). You can purchase very large screens of up to 40 or more inches (All these measurements are diagonal measurements from upper left to lower right corners.).

The resolution of a screen is normally the number of pixels that used to display a full screen image, or you might say the "fineness" of the detail that it can display. It is really a function of both screen size and something called "dot-pitch".

The "Bus" is a problem with video - originally with the ISA bus, we could only move about 8 MB/s over the 16 bit ISA bus to a video card. With the advent of the VESA Local Bus, we could move a theoretical 132MB/s if we had a 33MHz system bus interface.

Then the PCI bus allowed much higher speeds and could handle system bus speeds of 66MHz. A VESA Local Bus interface was common on many 486 processors, and the PCI bus is most common on Pentium and later systems.

Just remember: The slower the expansion bus, the poorer the quality. The bus is on the motherboard, so if you want to upgrade, you may need a new motherboard!

Resolution is often referred to as a type of standard (the first number means horizontal pixels (640), the second means vertical pixels (200)):

The Video Adapter Card is another component that helps with total picture quality. The information going to the monitor or CRT must pass through the video adapter, and the video adapter must be able to send information to the screen in the format required and at the proper speeds. However, for a video card to work properly, you must have a high quality monitor.

What we really want is exceptional "picture quality".  We mentioned resolution and "dot-pitch" above, but that is only part of total picture quality.

There are other factors that determine the picture quality.

NOTE: Laptop Screen types such as LED, LCD, or Gas-Plasma use different methods to display information on the screen.

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