If you were building a tube amplifier in the early 1990s ... still use travelling wave tubes, and very high power industrial equipment that uses vacuum and gas-filled tubes for control or ...

Vacuum tubes fueled a technological revolution. They made the amplification of signals a reality for transatlantic telephone cables (and transcontinental ones too), they performed logic for early ...

Long the backbone of electronics, semiconductors are finding new uses in the development of electronic noses and tongues.