What is VDT?
Visual display terminal or video display (VDT) is a computer screen. VDT shows text and images generated by computer. VDT can be part of a computer or a separate hardware device connected to a computer with a cable. These separate devices are sometimes called computer monitors. Today's VDT can reproduce millions of colors, all created by mixing the primary colors of red, green and blue.
shows reproductive text and images using pixels. Pixel is the smallest color unit of the reproduced VDT. The size of the pixel depends on the screen resolution. The higher the resolution, the smaller the pixel and the sharper the image. VDTS project pixels on the screen using different types of technology. CRT is a vacuum tubing a similar picture on TV. Electricity moves back and forth through the screen and hits phosphor dots on the inside of the tube. Like TVs, VDTs that use these tubes are bulky and heavy. Flat panel displays can be compared to DSPlei CRT, which can be more than wide legs, several inches. LCD and gas plasma are two common types of flat panels.
LCD screens have been used since the 80s in digital hours and calculators. LCD screens are now commonly found in laptops and other small computers. These screens are ignited using a fluorescent light or emitting light (LED). The rear light is always on and the images are reproduced to VDT by blocking the parts of the light.
Pass Electricity Passed via a liquid crystal inside the screen changes the polarity of the crystal. Polarized crystal blocks light. The filter located in front of the rear light changes the color of the light that is not blocked and projected on the VDT.
plasma screens work using gas instead of liquid crystal. They have small chambers filled with plasma gas on the screen. The color is added to the gas by mixing phosphorus and electricity in a way similar toThe way the color projected on the CRT screen. Originally plasma screens used more energy than LCD screens. Improved technology has since improved the energy efficiency of VDT in plasma.