thermionic tube
Meaning
A thermionic tube is a vacuum device that controls current via a heated cathode emitting electrons. It powered early radios, amplifiers, and computers, and is also called a vacuum tube or valve.
Synonyms
Hyponyms
Examples
Technical difficulties of all sorts have been ignored, certainly, but also ignored are means as yet unknown which may come any day to accelerate technical progress as violently as did the advent of the thermionic tube.