Traveling-wave tube
![Cutaway view of a helix TWT. (1) Electron gun; (2) RF input; (3) Magnets; (4) Attenuator; (5) Helix coil; (6) RF output; (7) Vacuum tube;](/Images/godic/202501/14/TWTA0743.png")
![Ruselectronics TWT from the 1980s used in the Russian Gorizont communication satellites](/Images/godic/202501/14/TWT_Shtormovka0743.jpg")
![Diagram of helix TWT](/Images/godic/202501/14/Traveling_wave_tube_diagram0743.png")
![Soviet UV-1008 (УВ-1008) TWT from 1976, with waveguide input and output](/Images/godic/202501/14/Uv_1008_19760743.jpg")
A traveling-wave tube (TWT) is a specialized vacuum tube that is used in electronics to amplify radio frequency (RF) signals in the microwave range. The TWT belongs to a category of "linear beam" tubes, such as the klystron, in which the radio wave is amplified by absorbing power from a beam of electrons as it passes down the tube. Although there are various types of TWT, two major categories are: