English engineer John Ambrose Fleming received a patent for the thermionic valve, better known as the vacuum tube, on November 16, 1904.

The two-electrode vacuum-tube rectifier, which Fleming called the oscillation valve, and some peers called the Fleming valve, was a major breakthrough. However, whether the breakthrough actually belonged to Fleming was debated in and out of court.

The United States Supreme Court eventually invalidated the patent because of an improper disclaimer and maintained that the technology in the patent was known art when filed.

Even still, Fleming continued to work on his diode and saw its use in radio receivers and radars for many decades afterward, until it was superseded by solid state electronic technology.