Dictionary of Electrical Engineering

Commonly used terms in the Electrical industry.

in electrical systems, any of a variety of electromechanical devices that convert mechanical power into electrical power, typically via Faraday induction effects between moving and stationary current-carrying coils and/or magnets. Electrostatic generators use mechanical motion to physically separate stationary charges to produce a large electrostatic potential between two electrodes.
generator coherency
a group of generators where the rotor angles swing in synchronism with one another following a disturbance. Usually, generators in close electrical proximity and at some distance from the fault tend to be coherent.
generator differential relay
a generator differential relay is a differential relay specifically designed for protection of electric power generators. Variations include allowances for split-phase winding machines.
generator inertia constant
a term proportional to the combined moment of inertia of the turbine-generator mass.
geometric transformation
transforms the pixel co-ordinates of an image to effect a change in the spatial relationships of elements in the image. The change often takes the form of a stretching or warping of the image.
geothermal energy
thermal energy in the form of hot water and steam in the earth's crust.

See ground-fault circuit interrupter

See ground fault interrupter
common notation for current gain. GI is dimensionless.
glass laser
laser in which the host medium for doping with laser atoms is a glass.
(1) an incorrect state of a signal that lasts a short time compared to the clock period of the circuit. The use of "glitch" in describing power systems is generally avoided. hazard.

(2) slang for a transient that causes equipment crashes, loss of data, or data errors. global alignment a method of alignment where the mask is aligned globally to the whole wafer (as opposed to field-by-field alignment).
global positioning system (GPS)
system of 18 primary satellites in medium earth orbit, distributed so that at least four are simultaneously visible from each point on the globe; typically used in timing and positioning applications.
Global System for Mobile Communications (GSM)
a set of systems specifications that describe the Pan European digital mobile cellular radio system. This set of 13 recommendations describe service, synchronization, hardware, operating and maintenance characteristics for the system.
globally asymptotically stable equilibrium
an asymptotically stable equilibrium (see the definition) with a region of attraction (see the definition) equal to
globally asymptotically stable state

See asymptotically stable in the large
in power line work, this refers to conductors which are energized with voltages low enough to be safely contacted by workers wearing suitable rubber gloves, to the range of voltages at which the practice is allowed, and to the gloves themselves.
common notation for DC transconductance.

See gas metal arc welding
head the top of a tower.
a device connected to a rotating machine by which the speed-regulating system is automatically adjusted to maintain constant speed under various load conditions.