Braun tube

A Braun tube, also known as a cathode ray tube (CRT), is an early type of display device used in televisions and monitors. Inside a sealed glass screen, an electron gun fires a stream of tiny electrons toward a phosphorescent screen. When the electrons hit the screen, they make it glow in specific colors, creating images. Magnetic or electric fields steer the electron beam to form pictures line by line. Though largely replaced by newer technologies, Braun tubes played a key role in the development of electronic displays.