Radio receiver crude triode, was invented in 1906 by Lee De Forest as a more sensitive detector for radio receivers, by adding a third electrode to the thermionic diode detector, the Fleming valve. It was not widely used until its amplifying ability was recognized around 1912. The first tube receivers, invented by De Forest and built by hobbyists until the mid 1920s, used a single Audion which functioned as a grid-leak detector which both rectified and amplified the radio signal. There was uncertainty about the operating principle of the Audion until Edwin Armstrong explained both its amplifying and demodulating functions in a
Owen Williams (engineer) excelled in mathematics. He was apprenticed to the Electrical Tramways Co. in London in 1907 and at the same time did an engineering degree at the University of London. In 1912 Williams assumed a position as engineer and designer with the Trussed Concrete Company. Seven years later, he started his own consulting firm, Williams Concrete Structures. He was then appointed chief consulting civil engineer to the British Empire Exhibition which included the old Wembley Stadium. The commission also included the Palace of Industry building in Brent, the first building in the United Kingdom to use concrete as the exterior. The