Dictionary of Electrical Engineering

Commonly used terms in the Electrical industry.

expulsion tube arrester
a gapped lightning arrester which establishes the power-follow arc in a tube lined with a substance which generates a sufficient quantity of gas when heated to blow out the arc. See power follow, lightning arrestor.
extended source
a (light) source in which rays are emitted from a large source area. Compare with point source.
externally vented machine
classification describing an electrical machine constructed with an open frame in which ventilation air is forced through the machine by blower(s) mounted outside the machine enclosure.
extinction angle
time in electrical degrees from the instant the current in a valve reaches zero (end of conduction) to the time the valve voltage changes sign and becomes positive.
extinction cross section
the sum of the scattering and the absorption cross sections.
associated with the outside or exterior. In devices and device modeling, extrinsic refers to that part of the device or model associated with the passive structures that provide interconnects and contacts to other components, but are still considered a part of the device.
extrinsic fiber optic sensor
a fiber optic sensor where the fiber delivers light to and from a sensing element external to the fiber. Chemical sensors are an example where the sensing element exhibits a change in optical property such as absorption, fluorescence or phosphorescence upon detection of the species to be measured.