High Speed Cathode Ray Tube (TV)

Описание: If you want to know how a TV works, click the "more info" button below. This is a high speed video, shot at 420FPS of a cathode ray tube television. This is just static, but you can still see the way that these older types of televisions worked. Now most people use LCD or Plasma TVs, but those are not very interesting to look at in high speed.

How this type of TV works is that there is a tube inside of it called the Cathode Ray Tube (CRT) which is the screen that you are looking at. Electricity at the back of it provides the negative charge (cathode) while a part of the tube further down provides the positive charge (anode). This cathode/anode arrangement is called the electron gun. It accelerates a small ray of electrons at the screen's center, which would cause just a small, white dot to form in the middle of the screen. The reason that the entire screen can be covered by light is because this stream of electrons is magnetic, and is affected by an electromagnet that can control the position of the dot at extremely high speed. To make actual images appear on the screen, an electronic device inside the television receives the signal, and converts it into the electronic pattern in the TV that can actually be used in the television. Elsewhere inside the TV, there is a device that simply controls the electromagnet, causing it to cross the screen horizontally at extremely high speeds that even this camera did not pick up. Then, as it sweeps horizontally across the screen, it more slowly passes vertically from the top of the screen down. The image is a series of on/off patterns in the electron gun, causing the pattern of the motion on the screen to resemble the image input into the TV. The phosphorescent screen retains some of the energy for a small amount of time, and because of that, the image remains as a glow-in-the-dark image for a fraction of a second. This allows you to see the images as a continuous video, instead of a blinking series of photos. The different colors come from different small pieces of pixels on the screen. There is a red, a green, and a blue on each pixel, that glows differently based on the amount of energy it receives. At the size of these individual color sections of each pixel, your eye will conceive them as one color each, and with all the different pixels, it will conceive an image. The reason that the TV needs to use a phosphorescent screen, is because the electron ray is not visible on its own.