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A computer display or monitor is a computer peripheral device capable of showing still or moving images generated by a computer. It is driven by a graphics card and generally conform to one or more display standards.

There are several different technologies used for displaying the actual image as with television:

A modern CRT display is quite flexible. It can often handle all resolutions from 640x480 up to 1600x1200 with 32-bit colour and a variety of refresh rates.

In some technical circles, the name "display" is preferred over "monitor" which is ambiguous with the other senses of "monitor" meaning "machine-level debugger" or "thread synchronization mechanism." Computer displays have also been known as visual display units or VDUs.

Early CRT-based VDUs that were incapable of graphics were known as 'glass teletypes', because of the similarity to their electromechanical predecessors.

Monochome displays can only display one colour either as on or off. Grayscale displays, can show only levels of a single colour. In both cases the display was usually green, orange or gray (white).

Colour monitors may show either digital colour (each of the red, green and blue signals may be either on or off, giving eight possible colours: black, white, red, green, blue, cyan, magenta and yellow) or analog colour (red, green and blue signals are continuously variable allowing any combination to be displayed). Digital monitors are sometimes known as TTL because the voltages on the red, green and blue inputs are compatible with TTL logic chips.

Most modern computer displays can show thousands or millions of different colours in the RGB colour space by combining red, green, and blue dots in varying intensities.

Some display technologies (especially LCD) have an inherent misregistration of the colour planes, that is, the centers of the red, green, and blue dots do not line up perfectly. In 2001, software designers began to exploit the misregistration to produce sharper images such as Microsoft's technology called ClearType™.

Moving texts can be in italics, even when the display resolution is too low to show static italics: an apparent shift of a fraction of a pixel is obtained by a corresponding time delay.