The term " thermionic emission " is now also used to refer to any thermally-excited charge emission process, even when the charge is emitted from one solid-state region into another.
42.
Following J . J . Thomson's identification of the electron in 1897, the British physicist Owen Willans Richardson began work on the topic that he later called " thermionic emission ".
43.
The work function is important in the theory of thermionic emission, where thermal fluctuations provide enough energy to " evaporate " electrons out of a hot material ( called the'emitter') into the vacuum.
44.
Thermionic emission is the flow of electrons from a heated charged metal or metal oxide surface, caused by thermal vibrational energy overcoming the work function ( electrostatic forces holding electrons to the surface ).
45.
Electrons are usually generated in an electron microscope by a process known as thermionic emission from a filament, usually tungsten, in the same manner as a light bulb, or alternatively by field electron emission.
46.
Included in this portion of the syllabus are thermionic emissions with their characteristic curves, diodes, triodes and multi-electrode valves; and the use of valves as rectifiers, oscillators, amplifiers, detectors and frequency changers, stabilisation and smoothing.
47.
The filament emitted electrons by thermionic emission ( the Edison effect ), discovered by Thomas Edison in 1884, and a positive voltage on the plate caused a current of electrons through the tube from filament to plate.
48.
The source of energy causing the electron emission can be heat ( thermionic emission ), light ( photoelectron emission ), ions, or neutral particles, but normally excludes field emission and other methods involving a point source or tip microscopy.
49.
His influence on the development of solid state physics extends to a deep understanding of many facets such as surface physics, of thermionic emission, of transport phenomena in semiconductors and of collective excitations in solids such as spin waves.
50.
:: : The magnetron that is the heart of the microwave oven is a vacuum tube and like most vacuum tubes, it includes a heater that must heat up before thermionic emission of electrons can begin inside that vacuum tube.
