John Ambrose Fleming

Fleming is best known for inventing the two-electrode rectifier, known as the Fleming valve or vacuum tube, which he patented in 1904. This device became the absolute foundation for the rapidly expanding field of electronics and radio broadcasting.

Before inventing the vacuum tube, Fleming worked extensively with early wireless technology, serving as a scientific advisor to the Marconi Company. He designed the power plant and transmitter for the first transatlantic wireless message sent by Guglielmo Marconi.

The Fleming valve utilized the Edison effect, operating as a diode that allowed electrical current to flow in only one direction. This ability to rectify alternating current into direct current and detect weak radio signals made it an indispensable component in early radio receivers.

He was a prominent English physicist and electrical engineer who studied under James Clerk Maxwell at Cambridge. He later became a professor at University College London, where he established England's first electrical engineering laboratory.