CRTs

CRTs, or cathode ray tubes, are vacuum-sealed glass devices that create images by directing electron beams onto phosphor-coated screens. They were the dominant display technology for televisions and computer monitors from the mid-20th century until the early 2000s.

A CRT contains a sealed glass envelope with an electron gun, a high-voltage anode, and a deflection system. Electrons are emitted by the gun, accelerated toward the screen, and steered by magnetic fields in a raster sweep across the phosphor-coated surface to form an image.

In color CRTs, three electron guns emit red, green, and blue electrons that strike a phosphor screen behind a shadow mask or aperture grille to form full-color images. Focus and convergence controls ensure sharpness and correct alignment of the colors.

CRTs offer high contrast, fast response, and wide viewing angles, with strong color depth. They are bulky, heavy, and power-hungry, and prone to burn-in and geometric distortion. They are also sensitive to magnetic fields and can implode if the glass is damaged.

Their use declined with flat-panel displays such as LCDs and LEDs, though CRTs remain in some specialized equipment and retro gaming setups. Typical lifespans range from 20,000 to 30,000 hours, depending on usage and care.

Safety and disposal require caution: CRTs contain leaded glass and high-voltage circuitry, and recycling programs recover valuable materials.