Robert von Lieben
Robert von Lieben was a self-taught Austrian physicist known for developing one of the first telephone amplifier valves using a cathode beam relay.
Von Lieben was born to a wealthy family in Vienna in 1878. Although he did not obtain an engineering degree, his parents’ fortune enabled him to pursue his scientific curiosity outside of a formal university setting. He collaborated in his early twenties with of the leading figures in Austrian physics, Walther Nernst, whose laboratory developed the electrochemical phonograph. He also interned at the engineering company Siemens-Schuckertwerke.
In 1906, von Lieben obtained a patent for a cathode-beam relay, which purported to amplify electrical signals of any frequency by feeding the tube with electromagnetic or electrostatic signals.
He improved this design in the following years. In 1910, he patented a cathode-beam relay with a control grid that improved its reliability. The new valves were filled with mercury vapor to help achieve a high vacuum.
Von Lieben’s research was performed in partnership with a number of large German electrical firms—AEG, Siemens & Halske, and Telefunken—under the aegis of the German government, which sought to bolster the empire’s technological advantages. They would continue to develop the Lieben valve after its inventor’s early death in 1913.
Oskar Blumtritt, The Lieben Valve: A German "Universal Amplifier" (June 2004).