# 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.

electromagnetic surveying (s) (noun), electromagnetic surveyings (pl)
A method of prospecting below the surface of the earth: The process involves the use of electromagnetic surveying during which the use of electric current waves on the top level are utilized to penetrate into the soil and to indicate if there are any new ores down below.

Such electromagnetic surveying can determine if there is gold, silver, or other metals by finding them and then recording their existence to those who are looking for the minerals.

electromagnetic susceptibility
1. A measure of the tolerance of a circuit to undesired electromagnetic energy.
2. The tolerance of circuits and components to all sources of interfering electromagnetic energy.
electromagnetic system of units, electromagnetic units, emu (noun) (plural used as a singular)
1. A system of electrical units, based on the centimeter, gram, and second, in which a unit of magnetic pole is by definition such that two units of the same sign placed one centimeter apart in free space will repel each other with a force of one dyne.

Units in the system are usually presented with the prefix ab-; such as, abampere, abvolt, etc.

2. A centimeter-gram-second system of electric and magnetic units in which the unit of current is defined as the current which, if maintained in two straight parallel wires having infinite length and being one centimeter apart in vacuum, would produce between these conductors a force of two dynes (units of force) per centimeter of length.

Other units are derived from this definition by assigning unit coefficients in equations relating electric and magnetic quantities.

electromagnetic tester
1. A nondestructive test method for engineering materials, including magnetic materials, that use electromagnetic energy having frequencies less than those of visible light to yield information regarding the quality of the tested materials.
2. The theory of the propagation of energy by the combined electric and magnetic fields which are included in Maxwell's equations.

Maxwell's equations refers to the fundamental equations, developed by J.C. Maxwell, for expressing radiation mathematically and describing the condition at any point under the influence of varying electric and magnetic fields.

electromagnetic theory
The theory of propagation of energy by the combined electric and magnetic fields included in Maxwell's equations.

See electromagnetic theory of light or take a look at production and interrelation of electric and magnetic fields, Maxwell's equations for explanations of what the term, Maxwell's equations, is all about.

electromagnetic theory of light
1. The theory which states that electromagnetic and light waves have identical properties.
2. The theory that light consists of electromagnetic radiation and therefore obeys Maxwell's equations; contrasted with earlier concepts that light was a stream of tiny particles or light was a wave in a medium of ether.

Maxwell's equations consists of the four fundamental equations that describe the behavior of electric and magnetic fields in time and space and the dependence of these fields on the distribution and behavior of electric charges and currents.

These four partial differential equations relate to the electric and magnetic fields to their sources, charge density, and current density.

electromagnetic transduction (s) (noun), electromagnetic transductions (pl)
1. A wave produced by the oscillation of an electric charge or a wave in which there are both electric and magnetic displacements.
2. A transverse wave associated with the transmission of electromagnetic energy.
electromagnetic transduction device (s) (noun), electromagnetic transduction devices (pl)
Instruments that consist of a magnet, generally rare earth (either samarium cobalt or neodymium iron boron), and an energizing coil.

The magnet is attached to the ossicular chain (any of certain small bones, as those of the middle ear), tympanic membrane, or the inner ear (round window or fenestra).

A fluctuating magnetic field is generated when the coil is energized by a signal, which corresponds to an acoustic input and this magnetic field causes the magnet to vibrate.

The vibrating magnet, in turn, causes movement of either the ossicular chain or the cochlear fluids directly.

The force generated is inversely proportional to the square of the distance between the coil and magnet (e.g., doubling the distance between the magnet and coil results in an output of one-fourth the force); therefore, these two components must be maintained in close proximity to one another to realize an efficient system.

electromagnetic unit, EMU (noun) (s)
1. A unit based primarily on the magnetic effect of an electric current.
2. Any unit in the centimeter-gram-second system of units for measuring electricity and magnetism that gives a value of one to the magnetic constant; for example, the abampere, abfarad, abhenry, or the abvolt.
electromagnetic vibrator
A mechanical instrument for interrupting the flow of direct electric current and thereby making it a pulsating current.

This takes place when a circuit requires an alternating current to operate and a reed within the vibrator is alternately attracted to two electromagnets.

electromagnetic vulnerability (s) (noun), electromagnetic vulnerabilities (pl)
The characteristics of electromagnetic vulnerabilities consist of a system that can cause it to suffer a definite degradation (incapability of performing a designated mission) as a result of having been subjected to a certain level of electromagnetic environmental effects.
—Dictionary of Military and Associated Terms; US Department of Defense.
electromagnetic wave
1. An oscillation of the electric or magnetic field associated with the propagation of electromagnetic radiation.
2. A wave which consists of both electric and magnetic variation.
3. A wave of electromagnetic radiation generated by the oscillation of a charged particle and characterized by periodic variations of electric and magnetic fields.
4. A wave of energy made up of an electric and a magnetic field which is generated when an electric charge oscillates or is accelerated.

Light waves and radio waves are electromagnetic waves, according to their frequencies and wavelengths.

The primary kinds of electromagnetic waves, ranging from the longest to the shortest wave length, are long radio waves, short radio waves, infrared rays, visible light, ultraviolet light, X-rays, and gamma rays.

electromagnetic wave filter, electromagnetic-wave filter
1. A device that allows electromagnetic waves of certain frequencies to pass while effectively attenuating (weakening) others.
2. Any device to transmit electromagnetic waves of desired frequencies while substantially reducing the strength of all of the other frequencies.
electromagnetic waves
Any of a continuous spectrum of waves propagated by simultaneous oscillation of electric and magnetic fields perpendicular to each other and both perpendicularly to the direction of the propagation of the waves.

Included in the spectrum, in the order of increasing frequency (or decreasing wavelength) are the following types of waves: radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

electromagnetical
1. Electromagnetism or the magnetism produced by a current of electricity.
2. A reference to the branch of physics which deals with electricity and magnetism.

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.