A Braun tube is a type of cathode ray tube (CRT) used primarily in oscilloscopes and other electronic devices to display waveforms and signals. It works by directing a beam of electrons onto a phosphorescent screen, which lights up to create visual representations of electrical signals. This technology was developed in the late 19th century and has been essential in the field of electronics for analyzing and troubleshooting circuits. The Braun tube is named after the German physicist Karl Ferdinand Braun, who invented it in 1897. While modern technology has largely replaced CRTs with flat-panel displays, the Braun tube remains significant in the history of electronics and is still appreciated for its role in the development of early television and radar systems.