Space 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 emitted from some region of a solid—the cloud of emitted carriers can form a space charge region if they are sufficiently spread out, or the charged atoms or molecules left behind in the solid can form a space charge region. Space charge usually only occurs in dielectric media (including vacuum) because in a conductive medium the charge tends to be rapidly neutralized or screened. The sign of the space charge can be either negative or positive. This situation is perhaps most familiar in the area near a metal object when it is heated to incandescence in a vacuum. This effect was first observed by Thomas Edison in light bulb filaments, where it is sometimes called the Edison effect, but space charge is a significant phenomenon in many vacuum and solid-state electronic devices.
Other articles related to "space charge, charge":
... Space charge tends to reduce shot noise ... Shot noise results from the random arrivals of discrete charge the statistical variation in the arrivals produces shot noise ... A space charge develops a potential that slows the carriers down ...
... tool for studying electrically active defects (known as charge carrier traps) in semiconductors ... DLTS investigates defects present in a space charge (depletion) region of a simple electronic device ... This voltage pulse reduces the electric field in the space charge region and allows free carriers from the semiconductor bulk to penetrate this region and recharge the defects causing their non-equilibrium ...
... The perveance defines the space charge limited current that can be emitted from a device ... TC electron emission will occur in one of two different regimes temperature or space charge limited current flow ... are accelerated enough by the electron gun to escape the space charge ...
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—Blaise Pascal (16231662)