LAUSR

Vacuum tubes appeared at the break of the 20th century, giving birth to electronics [1]. By the 1930s, they had become established as a mature technology, spreading into areas such as radio communications, longdistance radiotelegraphy, radio broadcasting, telephone communication and switching, sound recording and playing, television, radar, and air navigation [2]. During World War II, vacuum tubes were used in the first electronic computers, which were built in the United Kingdom and the United States [3]. Although vacuum tubes had been a successful technology, they were also bulky, fragile, and expensive; had a short life; and consumed a lot of power to heat the thermo emitters. These drawbacks promoted the search for completely new devices. Alternative solutions had long been considered but without significant developments.