This day in tech 1904- vacuum tube invented

British electrical engineer John Ambrose Fleming invented the thermionic valve.
Photo: Hulton-Deutsch Collection / Corbis

1904: British engineer John Ambrose Fleming invents and patents the thermionic valve, the first vacuum tube. With this advance, the age of modern wireless electronics is born.

Although the Supreme Court eventually invalidated Fleming's U.S. patent -- ruling that the technology he used for his invention was already known -- he remains the acknowledged inventor of the vacuum tube, a diode (having two electrodes) that would have far-reaching applications. The tube was standard equipment in radio receivers, radar sets, early television sets and other forms of electronic communication for at least half a century, until it was replaced by solid-state electronics in the mid-20th century.