In this case, the electron gun acceleration potential limits the emission current.
2.
After flashing the emission current is high but unstable.
3.
The emission current density " J " varies from position to position across the emitter surface.
4.
In this case, the emission current is regulated by the thermionic emission process, given by the Richardson Dushman equation.
5.
The thermionic emission current density, J, rises rapidly with increasing temperature, releasing a significant number of electrons into the vacuum near the surface.
6.
The emission current as given above is many times greater than that normally collected by the electrodes, except in some pulsed valves such as the cavity magnetron.
7.
The total emission current " i " from a defined part of the emitter is obtained by integrating " J " across this part.
8.
In 1926, Rother, using a still newer platform galvanometer of sensitivity 26 pA, measured the field emission currents in a " hard " vacuum between closely spaced electrodes.
9.
The solution was to add another grid between the screen grid and the main anode, called the suppressor grid ( since it suppressed secondary emission current toward the screen grid ).
10.
For practical emitters, the emission current density used in Fowler-Nordheim-type equations is always the current density at some reference point ( though this is usually not stated ).
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