Triode were invented, Philipp Lenard used the principle of grid control while conducting photoelectric experiments in 1902. The first vacuum tube used in radio was the thermionic diode or Fleming valve, invented by John Ambrose Fleming in 1904 as a detector for radio receivers. It was an evacuated glass bulb containing two electrodes, a heated filament and a plate (anode). Triodes came about in 1906 when American engineer Lee De Forest and Austrian physicist Robert von Lieben independently patented tubes that added a third electrode, a grid, between the filament and plate to control current. Von Lieben's partially-evacuated three-element tube, patented
Howard Johnson (electrical engineer) off with his last post "Seek inspiration" on 24 June 2013. Howard Johnson (electrical engineer) Howard Johnson is an electrical engineer, known for his consulting work and commonly referenced books on the topic of signal integrity, especially for high speed electronic circuit design. He served as the chief technical editor for Fast Ethernet and Gigabit Ethernet standardisation, and was recognized by the IEEE as an "Outstanding Contributor" to the IEEE P802.3z Gigabit Task Force. Johnson earned his Bachelor of Science in Electrical Engineering (1978), Masters of Electrical Engineering (1979), and PhD (1982) from Rice University. His dissertation was titled "The