In 1849, when Ambrose Fleming was born in the manse of a Congregational minister in Lancaster, England, the telegraph was only five years old. By the time of his dead nearly a hundred years later, in 1945, Fleming's invention originally known as Fleming's Valve had ushered in the age of radio and television.

When Ambrose was four, his father accepted a call to a new Church in London. In the ensuing years, the boy dabbed in electricity and magnetism and came under the spell of Michael Faraday's famous science lectures for children at the Royal Institution. Later, spurred by Faraday's example to become a scientist, he pursued scientific studies at the University College, London, and obtained his bachelor's degree in 1870. In 1877, after teaching science for a time, Fleming won admission to St. John's College, Cambridge University, where he could sit at the feet of the brilliant physicist James Clerk Maxwell. Fleming became one of Maxwell's star pupils and was often the only student attending Maxwell's lectures. Of Maxwell, Fleming later commented: "He saw so much deeper into scientific problems than ordinary persons that his utterances often appeared obscure." Fleming joined Maxwell's research staff at the Cavendish Laboratory and designed a special version of the Wheatstone bridge for accurately comparing standards of resistance. Maxwell promptly dubbed the device "Fleming's banjo."

In 1879, Fleming earned his doctorate in science at London University. After serving for a short time as a professor of mathematics and physics, he became a consultant to the fledgling Edison Electric Light Company. Then in, 1885, he became the first professor of the new science of electrical engineering at his alma mater, University College, London, where he served for forty-one years. He often quipped that the only equipment in the electrical engineering department when he began consisted of a blackboard and a piece of chalk! (CHEAP!) During these years, he conducted notable research in many fields, particularly in the study of properties of materials at the low temperatures and in photometry (the measurement of light intensity).

Some years later, Fleming began investigating the strange phenomenon known as the Edison effect. He soon developed a vacuum tube that could change, or rectify, high-frequency alternating current into direct current. This device, which he called a thermionic diode, was patented in 1904. Because of this invention, Fleming undoubtedly must be credited as among that handful of men who launched the electronic age.

In 1929, Fleming was knighted by King George V of Great Britain for his scientific achievements, and Dr. Fleming became Sir John Ambrose Fleming.

A Timeline of Fleming's life
1849 born in Lancaster, England
1870 receives his B.Sc degree
1877 begins graduate studies under Maxwell
1879 receives his D.Sc degree
1885 becomes a professor of electrical engineering
1901 helps Marconi transmit transatlantic wireless signals
1904 patents the thermionic diode
1929 knighted by the king
1930s helps start the Evolution Protest Movement;writes books opposing evolution
1945 dies in Sidmouth, England