vacuum tube

vacuum tube

Electron tube consisting of a sealed glass or metal enclosure from which the air has been withdrawn. It was used in early electronic circuitry to control a flow of electrons. In the first half of the 20th century, vacuum tubes allowed the development of radio broadcasting, long-distance telephone service, television, and the first electronic digital computers, which were the largest vacuum-tube systems ever built. Transistors have replaced them in virtually all applications, but they are still occasionally used in display devices for television sets and computers (cathode-ray tubes), in microwave ovens, and as high-frequency transmitters on space satellites.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on vacuum tube, visit

Seen & Heard

What made you look up vacuum tube? Please tell us what you were reading, watching or discussing that led you here.

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More