Katodstrålerör

Katodstrålerör, often abbreviated as CRT, is a vacuum tube containing one or more electron guns and a fluorescent screen, used to display images. In a CRT, an electron beam is accelerated and focused by an electron gun, then deflected by magnetic or electric fields. This deflected beam strikes the phosphorescent coating on the inside of the screen, causing it to glow and create a visible image.

The electron gun generates a stream of electrons by heating a cathode filament. These electrons are then accelerated towards the screen by a high voltage. Deflection coils or plates manipulate the path of the electron beam, allowing it to scan across the screen in a pattern, typically from left to right and top to bottom, line by line. The intensity of the electron beam is modulated to control the brightness of each point on the screen, forming the image.

CRTs were the dominant display technology for televisions and computer monitors for much of the 20th century. Their advantages included good color reproduction, fast response times, and high contrast. However, CRTs are bulky, heavy, and consume significant power. They also suffer from screen flicker and geometric distortions.

In recent decades, CRTs have been largely replaced by newer display technologies such as liquid crystal displays (LCDs), plasma displays, and organic light-emitting diodes (OLEDs), which offer thinner profiles, lower power consumption, and improved image quality. Despite their decline in consumer electronics, CRTs remain in use in some specialized applications, such as oscilloscopes and older medical imaging equipment.