electro-, electr-, electri-

(Greek > Latin: electric, electricity; from amber, resembling amber, generated from amber which when rubbed vigorously [as by friction], produced the effect of static electricity)

Electronics in our lives consists of numerous tools

Equipment which we use everyday relies on electronics to function including calculators, car controls, cameras, washing machines, medical scanners, mobile telephones, radar systems, computers; as well as many other applications or devices which are listed in this unit.

electrooculography, electro-oculography
1. Oculography in which electrodes placed on the skin adjacent to the eyes measure changes in standing potential between the front and back of the eyeball as the eyes move.
2. A sensitive electrical test for detection of retinal pigment epithelium dysfunction.
3. The study and interpretation of electroencephalograms made by moving the eyes a constant distance between two fixed points.
4. The recording and interpretation of the voltages which go with eye movements.

Eye-position voltages from electrodes placed on the skin near the eye are amplified and applied to a strip-chart recorder.

electro-optic coefficient
A measure of the extent to which the index of refraction changes with applied high electric fields; such as, several parts per ten thousand for applied fields of the order of twenty volts per centimeter.

Since the phase shift of a light wave is a function of the index or refraction of the medium in which it is propagating, the change in index can be used to phase modulate the light wave by shifting its phase at a particular point along the guide, by changing the propagation time to the point.

electro-optic deflection
The effect whereby a light beam is deflected by a birefringent prism when its polarization is changed by voltage applied to an electro-optical crystal through which the beam passes.

The deflection of the beam depends on its particular polarization.

electro-optic effect
The change in the index of refraction of a material when subjected to an electric field.

The effect can be used to modulate a light beam in a material since many properties; such as, light-conducting velocities, reflection, and transmission coefficients at interfaces, acceptance angles, critical angles, and transmission modes, are dependent on the refractive indexes of the media in which the light travels.

electrooptic material, electro-optic material
1. A material in which the indexes of refraction (a ratio of the speed of light in a vacuum relative to that speed through a given medium) are changed by an applied electric field.
2. A material having refractive indexes which can be altered by an applied electric field.
electro-optic modulator
An instrument that uses an applied electric field to alter the polarization properties of light.
electro-optic phase modulation
The modulation (variation of amplitude or frequency) of the phase of a light wave; such as, by changing the index of refraction and the velocity of propagation and hence the phase at a point in the medium in which the wave is propagating, in accordance with an applied field serving as the modulating signal.
electrooptic radar, electro-optic radar
1. A radar system which collects information by detecting the effects of an electric field on an optical observable fact.
2. A radar system using electrooptic, or electro-optic, techniques and equipment instead of microwave to perform an acquisition and tracking operation.
electro-optic shutter
A device used to control or to block a light beam by means of the Kerr electro-optical effect (a change in rotation of light reflected off a magnetic field).
electrooptical birefingence, electro-optical birefingence, electrooptical Kerr effect, electro-optical Kerr effect
1. A pattern of double refraction exhibited by certain refracting materials when exposed to an electric field.
2. Birefringence induced by an electric field or an optical property in which a single ray of unpolarized light splits into two components traveling at different velocities and in different directions.

In birefringent materials either the separation between neighboring atomic structural units is different in different directions, or the bonds tying such units together have different characteristics in different directions.

electrooptical character recognition, optical-character recognition, OCr
1. That branch of character recognition concerned with the automatic identification of handwritten or printed characters by any of various photoelectric methods.
2. A method for the machine-reading of typeset, typed, and, in some cases, hand-printed letters, numbers, and symbols using optical sensing and a computer.

The light reflected by a printed text; for example, is recorded as patterns of light and dark areas by an array of photoelectric cells in a optical scanner.

electro-optical detector
An instrument which detects radiation by utilizing influence of light in forming an electrical signal.

The detector may be a phototube; a photononductive, photovoltaic, or a photojunction cell; a phototransistor; or a thermal detector; such as, a thermocouple or a bolometer (a device for detecting and measuring small amounts of thermal radiation).

electro-optical effect, electro optical effect
1. The effect where certain transparent dielectrics become doubly refracting when placed in an electric field.
2. The change in the index of refraction of a material when subjected to an electric field.

The effect can b used to modulate a light beam in a material since many properties; such as, light-conduction velocities, reflection, and transmission coefficients at interfaces, acceptance angles, critical angles, and transmission modes, are dependent on the refractive indexes of the media in which the light travels.

electro-optical effect, electrooptical effect
The effect wherein certain transparent dielectrics (materials which are poor conductors of electric current) become doubly refracting (bending of electromagnetic waves as they pass between materials with different refractive indices or magnitude of some physical effect) when placed in an electric field.
electro-optical fingerprint recognition, electrooptical fingerprint recognition
A biometric technology that provides for the scanning, comparison, and identification of fingerprints without the traditional need for ink and paper.

An optical scanning and recognition system is used in conjunction with a matching system to enable efficient authentication for secure spaces and devices. Like other finger scanning technologies, electro-optical fingerprint recognition makes it possible to quickly and accurately compare a given fingerprint image to thousands of stored images.

Electro-optical fingerprint scanners are generally designed to be portable, easy to use, and physically rugged. The devices are becoming more widely used as an alternative to passwords for consumer electronics or as part of a two-factor authentication system where more stringent security is required.

The fingerprint is optically scanned directly from the finger and the resulting image is focused onto a small chip. The chip converts the focused image into a digital file that can be processed, stored, and compared with other fingerprint images.

The high-resolution digital images can be processed like any other scanned images, eliminating problems caused by aliasing (also called jaggies) and making it possible to quickly compare a fingerprint image with other fingerprint images in a large database.

The references or sources of information for compiling the words and definitions in this unit are listed at this Electronic Bibliography page or specific sources are indicated when they are appropriate.

A cross reference of word units that are related, directly and/or indirectly, with "electricity": galvano-; hodo-; ion-; piezo-; -tron; volt; biomechatronics, info; mechatronics, info.