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
Bob Adams (electrical engineer) Bob Adams (electrical engineer) Robert Whitlock Adams is a Technical Fellow at Analog Devices, Inc. (ADI) in Wilmington, Massachusetts. His focus is on signal processing and analog-to-digital conversion for professional audio. He is a leader in the development of sigma-delta converters, introducing architectural advances including mismatch shaping, multi-bit quantization, and continuous-time architectures. Adams graduated with a Bachelor of Science in Electrical Engineering from Tufts University in 1976. From 1977 to 1988 he worked for DBX, a professional audio recording company. There, he helped develop the industry's first audio converter with greater than 16-bit resolution, as well as one of the