tube
In electronics, vacuum tubes are devices that are used to amplify or modify signals, typically by manipulating the movement of electrons in vacuum space. In addition to the name of a vacuum tube, it is also called an electron tube, a thermionic tube, and a radio valve. It was once used in most electronic devices, but is now being replaced by smaller, cheaper transistors or semiconductors, integrated circuits, etc. in most electronic devices, and vacuum tubes are used only in high-power, high-power electronic devices.