Marc Amsler Marc Amsler Marc Amsler (born February 5, 1891 in Vevey, Switzerland – died May 3, 1968) was a professor of ophthalmology in the Eye Clinic at the University of Zurich. He took the position as professor of ophthalmology in Zurich in 1944. His predecessor was Prof. Alfred Vogt. Prior to assuming the position at Zurich, Dr. Amsler was chief ophthalmologist in Lausanne, since 1935. His predecessor there, under whom he worked beforehand, was Jules Gonin. During his time in Lausanne, Amsler was instrumental in creating the Jules Gonin Medal which is awarded every four years and is considered the highest
Control grid are strictly comparable, so there was no advance in this area. However, early screen-grid tetrodes of the 1920s, have C of only 1 or 2fF, around a thousand times less. 'Modern' pentodes have comparable values of C. Triodes were used in VHF amplifiers in 'grounded-grid' configuration, a circuit arrangement which prevents Miller feedback. Control grid The control grid is an electrode used in amplifying thermionic valves (vacuum tubes) such as the triode, tetrode and pentode, used to control the flow of electrons from the cathode to the anode (plate) electrode. The control grid usually consists of a cylindrical screen or