# electro-, electr-, electri-

### 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.

electrostatic field
1. An electric field that is associated with static (stationary, non-moving) electric charges.
2. An electric field with constant intensity; such as, that which is produced by stationary or static charges.
3. The region around an electrically charged subject which will induce an electrical charge on a second object, causing it to experience a force.

The voltage gradient or measure of the change of the physical quantity between two points at different potentials.

electrostatic fieldmeter
An apparatus with a non-contract probe or sensor for measuring the electrostatic field produced by a charged body.

It provides a measurement of the electrostatic field strength or the electrostatic voltage at a calibrated distance from a charged body.

electrostatic focus (s) (noun), electrostatic focuses (pl)
1. In television picture tubes, a technique of directing an electron beam in a cathode-ray tube by changing the voltage applied to the focusing electrode.
2. The production of a focused electron beam in a cathode-ray tube with the application of an electric field.
electrostatic focusing (s) (noun), electrostatic focusings (pl)
1. The point at which rays of light, heat, etc., meet, diverge, or seem to diverge after being reflected from a mirror, bent by a lens, etc.
2. A method of focusing the cathode-ray beam to a fine spot by the application of electrostatic potentials to one or more elements of an electron lens system.
electrostatic force, Coulomb force
1. The force exerted by stationary objects that are bearing an electric charge on other stationary objects bearing an electric charge.

If the charges are of the same sign, then the force is repulsive; if they are of opposite signs, the force is attractive.

The strength of the force is described by Coulomb's law or a law that was formulated by Charles Augustin de Coulomb (1736-1806), French physicist, which describes the electric forces between charged objects.

The law states that:

• like charges repel each other and unlike charges attract each other,
• the attraction or repulsion acts along the line between the two charges,
• the size of the force varies inversely as the square of the distance between the two charges,
• the size of the force is proportional to the value of each charge.

2. A force resulting from the attraction of stationary, charged bodies, proportional to the product of their magnitudes and inversely proportional to the square of the distance between them.
3. A force on a charged particle resulting from an electrostatic field, equal to the electric field vector times the charge of the particle.
4. Like charges in close proximity produce forces of repulsion between them; consequently, if two surfaces bear appreciable and approximately equal densities of charged groups on their surfaces appreciable forces of repulsion may occur between them.

The range of these forces is determined primarily by the ionic strength of the intervening medium, forces being of minimal range at high ionic strength.

The forces are effective over approximately twice the double layer of their thickness.

electrostatic galvanometer
A galvanometer or an instrument used to determine the presence, direction, and strength of an electric current in a conductor which is operated by the effects of two electric charges on each other.
electrostatic gyroscope
A gyroscope in which an electrostatic field supports a central beryllium ball (metal with a high ratio of strength to weight or the lightest structural metal known) that is surrounded by six electrodes in a vacuum inside a ceramic envelope.

A gyroscope is a mechanical or an optical tool which is used to maintain orientation during motion.

A mechanical gyroscope consists of a rapidly spinning wheel set in a framework that permits it to tilt freely in any direction or to rotate around any axis.

An optical gyroscope, laser or fiber, measures the interference pattern generated by two light beams, traveling in opposite directions inside a mirrored ring or fiber loop, in order to detect very small changes in motion.

Gyroscopes are utilized in compasses, in automatic pilots on ships and aircraft, in the steering mechanisms of torpedoes, in antiroll equipment on large ships, and in inertial guidance systems or resistance of objects to any changes in their status of motion.

An apparatus which is held against the ear that reproduces incoming electrical signals as sound.

It relies on changes in electrical charges across a diaphragm stretched between two perforated, polarized plates.

All parts of the diaphragm experience equal forces and the sound is inherently more linear.

electrostatic imaging
A radiographic technique in which the ionic charge liberated during the irradiation process is converted into a visible image.

The image may be produced by an electronic read-out device or by liquid or powdered toner.

electrostatic induction
1. The process of charging an object electrically by bringing it near another charged object, then touching it to a ground.
2. Modification in the distribution of an electric charge on one material under the influence of an electric charge on a nearby object which takes place whenever any object is placed in an electric field.
3. The production of an electric charge in an object when placed near a charged body.
4. A process of inducing stationary electric charges on an object by brining it near another object that has an excess of electric charges.

A positive charge will produce a negative charge, and a negative charge will produce a positive charge.

electrostatic instrument
1. A reference to an acoustical device; such as, a loudspeaker or microphone, which derives mechanical or electrical energy from the effect of an electrostatic field.
2. A meter which depends for its operation on the forces of attraction and repulsion between electrically charged bodies.
electrostatic interactions, Coulomb interactions
The charged particle interactions of charged particles associated with the Coulomb forces which they exert on one another.

It includes the forces between two charged particles; such as, between electrons and protons, that according to Coulomb's law is proportional to the product of the charges and inversely proportional to the square of the distance between them and which is either repulsive or attractive, to each other depending on the relationship of the charges.

electrostatic latent image
In an electrostatic copier, the invisible image formed on the zinc oxide coated paper by the action of light.
electrostatic lens
1. A collection of plates or cylinders with electrostatic properties which cause an electron beam to refract in a manner similar to the refraction of light by an optical lens.
2. An arrangement of electrostatic fields that acts upon beams of charged particles similar to the way a glass lens acts on light beams.
3. An electrostatic field with axial (a line of symmetry of an optical system, such as the line passing through the center of a lens) or a plane symmetry which acts upon beams of charged particles of uniform velocity; such as, glass lenses act on light beams.

The action of electrostatic fields with axial symmetry is similar to that of spherical glass lenses, whereas the action of electrostatic fields with plane symmetry is like that of cylindrical glass lenses.

electrostatic loudspeaker, capacitor loudspeaker
1. Any type of loudspeaker in which the mechanical energy is produced by the action of two electrically charged conductors; for example, a moving-coil microphone.
2. A loudspeaker in which the mechanical forces are produced by the action of electrostatic fields.

In one type, the fields are produced between a thin metal diaphragm and a rigid metal plate.

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.