What is the most basic output device of a computer?

The most basic output device of the computer is the "monitor". The display is the main tool for human-computer dialogue. It is a display tool that displays certain electronic files on the screen through a specific transmission device. It can display commands or data entered by the keyboard, and can also display the results of computer data processing. . There are two main types of commonly used monitors: 1. CRT monitor, used for desktop microcomputers; 2. LCD monitor, used for portable microcomputers.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

"Monitor" is the most basic output device of the computer.

Display, also known as monitor, is the main tool for realizing human-computer dialogue. It is a display tool that displays certain electronic files on the screen through a specific transmission device. It can not only display the commands or data entered by the keyboard, but also display the results of computer data processing.

The monitor is the computer screen (Computer Screen / Display). The monitor receives signals from the computer and forms an image, acting like a television receiver. Some computer screens use LCD displays. Computer screens are also called visual displays.

There are two main types of commonly used monitors.

• One is a CRT (Cath-odeRayTube, cathode ray tube) display, used for general desktop microcomputers;

  Divided by color: it can be divided into monochrome ( black and white) monitors and color monitors.

• The other is a liquid crystal (Liquid Crystal Display, LCD for short) display, used for portable microcomputers.

Color monitor is also called graphics monitor. It has two basic working modes: character mode and graphic mode. In character mode, the display content is based on standard characters, and the character glyphs are composed of dot matrix, which is stored in the glyph generator. In graphics mode, the display content is in pixels, and each point (pixel) on the screen can be controlled by the program for brightness and color, so higher quality graphics or images can be displayed.

Technical parameters

• Resolution

Resolution (Resolution) refers to the sum of pixels that make up the image, that is, how many pixels the screen contains. It is generally expressed as the product of horizontal resolution (the number of pixels in a scan line) and vertical resolution (the number of scan lines). For example, 1920×1080 means that the horizontal direction contains 1920 pixels and the vertical direction contains 1080 pixels. The total number of pixels on the screen is their product. The higher the resolution, the more pixels the picture contains, and the more detailed and clear the image is. The resolution of the display is affected by the size of the display, (pixel pitch of the picture tube), circuit characteristics, etc.

The resolution of the monitor is divided into three types: high, medium and low. The resolution indicator is expressed by the product of the number of pixels per line on the screen and the number of lines per frame (each screen image). The larger the product, that is, the smaller and larger the number of pixels, the higher the resolution and the clearer and more beautiful the graphics.

• Grating pitch and dot pitch

Grating pitch refers to the distance between parallel gratings of cathode picture tubes (unit: mm). The advantage of using a cathode-type picture tube is that its grid pitch will not deform after being used for a long time, and the display will not deteriorate in image quality after being used for many years.

Dot pitch (or stripe pitch) is a very important hardware indicator of the display. It refers to the distance between a luminous point of a given color and the nearest adjacent luminous point of the same color. This distance cannot be changed by software, which is different from the resolution. At any same resolution, the smaller the dot pitch, the clearer and more delicate the displayed image, and the higher the resolution and image quality.

• Bandwidth

Bandwidth is a very important parameter of the monitor, which can determine the performance of the monitor. The so-called bandwidth is the abbreviation of the display video amplifier passband width. The bandwidth of a circuit actually reflects the circuit's response speed to input signals and the resolution capability of the display. The wider the bandwidth, the smaller the inertia, the faster the response speed, the higher the signal frequency allowed to pass, and the smaller the signal distortion. The unit of bandwidth is MHz, and its value can be calculated using the formula "horizontal resolution × vertical resolution × refresh rate" [5].

• Refresh rate

The refresh rate of the monitor is divided into vertical refresh frequency and horizontal refresh frequency. The unit of vertical refresh rate (Vertical scanning frequency) is MHz, which is determined by the horizontal refresh rate and screen resolution. The vertical refresh rate indicates how many times the screen image is redrawn per second, that is, every second The number of screen refreshes [5] The horizontal refresh rate is called Horizontai scanning trequency, which refers to the number of times the monitor scans horizontal lines per second, and the unit is kHz;.

Display adapter

The display adapter, also known as the display controller, is the interface component between the display and the host. It is inserted into the computer in the form of a hardware card. on the motherboard. The resolution of the display is not only determined by the cathode ray tube itself, but also by the logic circuit of the display adapter. Commonly used adapters are:

(1) CGA (ColourGraphicAdapter) color graphics adapter, commonly known as CGA card, is suitable for low-resolution color and monochrome displays. The display modes it supports are:

character mode, 40 columns × 25 rows, 80 columns × 25 rows, 4 colors or 2 colors.

In graphics mode, 320×200, 4 colors; 640×200, 2 colors.

(2) EGA (EnhancedGraphicAdapter) enhanced graphics adapter, commonly known as EGA card, suitable for medium-resolution color graphics displays. The display modes it supports are: in character mode, 80×25 columns, 256 colors; in graphics mode, 640×350, 16 colors

Super EGA card supports 800×600, 16 colors.

(3) VGA (VideoGraphicArray) video graphics array, commonly known as VGA card, is suitable for high-resolution color graphics displays. The standard resolution is 640×480, 256 colors. Most of them are enhanced VGA cards, such as SuperVGA cards, etc., with resolutions of 800×600, 1024×768, etc., and 256 colors.

(4) Chinese display adapter

In the process of developing the Chinese character system, China has developed some display adapters that support Chinese characters, such as GW-104 card, CEGA card, CVGA card, etc., which solved the problem Fast display problem of Chinese characters.

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