In 1904, John Ambrose Fleming invented the first practical electron tube called the 'Fleming Valve', which is a diode rectifier. In 1906, Lee de Forest invented the audion later called the triode, which provided signal amplification.
On April 6, 1914, Hiram Percy Maxim proposed the formation of the American Radio Relay League.
4. Benjamin Franklin was a prolific inventor. He invented the lightning rod, the Franklin stove, studied electricity, discovered the Gulf Stream, started the first library, and on and on. Among his many other inventions, what musical instrument did he invent?
Ben also holds a lot of firsts - first U.S. ambassador, first political cartoonist, first American philosopher, organized the first fire department, and on and on.
5. Who among the following invented the small pox vaccine?
British inventor Frank Whittle was the first to patent his design for a jet engine in 1930. Although an engine designed by Dr. Hans Von Ohain was the first to fly in 1939. Whittle's jet engine first flew in 1941.