thermionic tube
61Work function — In solid state physics, the work function is the minimum energy (usually measured in electron volts) needed to remove an electron from a solid to a point immediately outside the solid surface (or energy needed to move an electron from the Fermi… …
62Cathode heater — A cathode heater is a filament used to heat the cathode in a vacuum tube or cathode ray tube. Before transistors and integrated circuits came into widespread use, electronic devices used vacuum tubes. The cathode element had to achieve the… …
63Thermoïonique — Vue rapprochée d une lampe au mercure à basse pression montrant une émission lumineuse autour de la partie centrale du filament. Cette émission lumineuse est provoquée par une émission thermoïonique. La couche blanche du filament est… …
64Space charge — is a concept in which excess electric charge is treated as a continuum of charge distributed over a region of space (either a volume or an area) rather than distinct point like charges. This model typically applies when charge carriers have been… …
65Albert Hull — Infobox Scientist name = Albert Wallace Hull box width = caption = Albert Wallace Hull birth date = birth date|1880|4|19 birth place = Southington, Connecticut death date = death date and age|1966|1|22|1880|4|19 death place = residence = United… …
66De Forest, Lee — born Aug. 26, 1873, Council Bluffs, Iowa, U.S. died June 30, 1961, Hollywood, Calif. U.S. inventor. He had invented many gadgets by age 13, including a working silverplating apparatus. After earning a Ph.D. from Yale University, he founded the De …
67Oscilloscope history — This article discusses the history and gradual development of the Oscilloscope. Contents 1 Hand drawn oscillograms 2 Automatic paper drawn oscillograph 3 Photographic oscillograph 4 …
68Electric current — Electromagnetism …
69Field emission — (FE) is the emission of electrons from the surface of a condensed phase into another phase due to the presence of high electric fields. In this phenomenon, electrons with energies below the Fermi level tunnel through the potential barrier at the… …
70Triode — A triode is an electronic amplification device having three active electrodes. The term most commonly applies to a vacuum tube (or valve in British English) with three elements: the filament or cathode, the grid, and the plate or anode. The… …
