cathode ray tubes

Cathode ray tubes, abbreviated CRT, are vacuum tubes that produce images by firing electron beams at a phosphorescent screen.

For most of the twentieth century, CRTs were the standard display technology in televisions and computer monitors, creating images line by line as the beam swept across the screen.

My old CRT monitor weighed a ton compared to modern flat screens.

The technology has been largely replaced by LCD and LED displays, though CRTs remain valued by some gamers and video professionals for their color accuracy and response time.