The introduction of vacuum tubes at the beginning of the 20th century was the starting point of the
rapid growth of electronics. With vacuum tubes the manipulation of signals became possible, which
could not be done with the early telegraph and telephone circuit or with the early transmitters that
used high-voltage sparks to create radio waves. The transistor, invented in 1948, has now almost
completely replaced the vacuum tube in most of its applications. The transistor provides the same
functions as the vacuum tube but at reduced cost, weight, and power consumption and with higher
reliability.
VACUUM TUBE
