1. Created by or relating to electromagnetism; that is, the interaction of electricity and magnetism.
2. Involving or relating the interaction of electric and magnetic fields, both static and dynamic.
3. A reference to magnetism that is induced by an electric current.
4. Pertaining to radiation; such as, light, microwaves, X-rays, gamma rays, or radio waves.
5. Referring to the combined electric and magnetic fields associated with radiation or movements of electrons or other charged particles through conductors or space.

1. A braking system whose force is supplied by an adjustable spring counteracted by a solenoid, a centrifugal thruster, and an actuator, in which the actuating force is supplied by current flowing through a solenoid or an electromagnet.
2. An emergency braking system which is automatically applied to an electric-powered apparatus when a power failure occurs.
3. An electric brake design in which the electromagnet is a small disc (spot) attached to an actuating lever is supplied by current flowing through a solenoid, or through an electromagnet which is attracted to disks on the rotating member, actuating the brake shoes.

This force is counteracted by the force of a compression spring.

4. The contact component of an electric braking system.

An electromagnetic system is a technology which is intended to replace the steam catapults that have been used on aircraft carriers since the mid-1950's.

The Navy plans to install the Electromagnetic Aircraft Launch System on the USS Gerald R. Ford, a next-generation aircraft carrier scheduled to go into service in 2015.

The Electromagnetic Aircraft Launch System technology is designed to handle newer, heavier, and faster aircraft than the traditional steam catapults, the Navy says.

The Navy says EMALS will provide "higher launch energy capacity;" improvements in system weight, maintenance, and efficiency; and greater accuracy of end-speed control and smooth acceleration at both high and low speeds".

The Electromagnetic Aircraft Launch System is a multimegawatt electric power system involving generators, energy storage, power conversion, a 100,000 hp electric motor, and an advanced technology closed loop control system with diagnostic health monitoring.

This technology reduces stress on airframes because they can be accelerated more gradually to a takeoff speed than steam-powered catapults.

A system composed of several waveguides that are symmetrically arranged with a related excitation medium in order to become excited with equal amplitudes and phases to in order to provide a net gain in energy.

An instrument for measuring electromagnetic forces by balancing them against gravity.

1. A cathode ray tube in which the beam of electrons produced in the tube's filament is deflected by a magnetic field.
2. A cathode-ray tube in which electromagnetic deflection is used on the electron beam.

1. A friction clutch that operates by the action of electric power from a dynamo on a magnetic coupling between conductors.
2. A clutch based on magnetic coupling between conductors; such as, a magnetic fluid and power clutch, an eddy-current clutch, or a hysteresis clutch.

Electromagnetic clutches operate electrically, but they transmit torque mechanically.

The use of an electromagnetic wave to pass information between two points.

1. The extent to which a piece of hardware will tolerate electrical interference from other equipment, and will interfere with other equipment.
2. The capability of electronic equipment or systems to be operated in the intended electromagnetic environment at design levels of efficiency.
3. The ability of electronic equipment and systems to operate in the proximity of electromechanical devices, without causing or suffering unacceptable degradation in output or performance.
4. The capacity of an appliance or circuit to function correctly in its intended electromagnetic environment without transmitting unwanted signals to adjacent equipment or receiving unwanted interference from nearby sources.

1. An electromagnetic configuration of an installation that includes all radiators of significant amounts of energy.
2. Electromagnetic configuration of an installation, including all significant radiators of energy.

1. All electromagnetic radiation, including light, radio transmission and electricity, travels at approximately 186,000 miles (300,000 kilometers) per second; more than seven times around the equator in one second. More precisely, the speed is 299,792,458 meters per second in a vacuum.
2. The speed of the propagation of electromagnetic waves in a vacuum.

1. A coupling between circuits or conductors that are mutually affected by the same electromagnetic field.
2. A coupling that exists between circuits when they are mutually affected by the same electromagnetic field.

An instrument that detects cracks in iron or steel objects by applying a strong magnetizing force and measuring the resulting magnetic flux through the object.

When a flawed portion passes through the magnetizing coil, the magnetic flux drops.

1. A movement of charged particles in the atmosphere giving rise to electric and magnetic fields; such as, those in the ionosphere that transmit radio signals.
2. Motions of charged particles; for example, in the ionosphere, that are giving rise to electric and magnetic fields.

1. The use of a magnetic field or external horizontal-deflection and vertical-deflection coils to deflect an electron beam in a television picture tube or an oscilloscope.
2. Deflection of an electron stream by means of a magnetic field.

In a television picture tube, the magnetic fields for horizontal and vertical deflection of the electron beam are produced by sending sawtooth currents through coils in a deflection yoke which goes around the neck of the picture tube.

1. A delay line the operation of which is based on the time of propagation of electromagnetic waves through distributed or lumped (concentrated) capacitance and inductance.
2. A delay line consisting simply of a transmission line carrying pulse trains.

The delay time generally available is not sufficient for storing a large number of pulses within a reasonable line length.

1. A random or periodic electromagnetic occurrence that is superimposed on a desired signal.
2. An electromagnetic development, usually impulsive, that is superimposed on a desired signal.

The disturbance may be random or periodic.

Forms of radiant energy associated with radio waves, heat waves, light waves, gamma rays, cosmic rays, X-rays, and other types of electromagnetic radiation.

1. The radio-frequency field or fields existing in a given area or desired in an area to be shielded.
2. The resulting product of the power and time distribution, in various frequency ranges, of the radiated or conducted electromagnetic emission levels that may be encountered by a military force, system, or platform when performing its assigned mission in its intended operational environment.

It is the sum of electromagnetic interference; electromagnetic pulse; hazards of electromagnetic radiation to personnel, ordnance, and volatile materials; and the natural phenomena effects of lightning and precipitation static.

An antisymmetric second-rank tensor whose elements are proportional to the electric and magnetic fields.

1. All forms of energy emanating from an electrical source and transmitted through the air.

Included are the fields produced by light, radio, X-rays, and gamma rays and the higher the frequency of the fields produced, the more energy is contained.

2. The combination of electric and magnetic fields that surround moving electrical charges (for example, electrons); such as, those in electric currents.

Electromagnetic fields apply a force on other charges and can induce current flows in nearby conductors.

3. An oscillating electric field and its associated magnetic field acting at right angles to each other and at right angles to their direction of motion.
4. The region surrounding a moving electric charge which consists of magnetic and electric force fields especially related; such as, to orientation and strength, and that possesses a definite amount of energy.
5. A field created by the interplay of an electric field and a magnetic field when an electric current passes through a wire.

An electromagnetic field consists of two kinds of energy: electrostatic (potential energy) and electrodynamic (kinetic energy).

1. An instrument that measures the rate of flow (movement of electric charges, gases, liquids), without interruption of the flow, by producing an electromagnetic field in a liquid that creates an interior current, proportional to the actual flow rate, which is detected by two electrodes.
2. A flowmeter that offers no obstruction to liquid flow.

Two coils produce an electromagnetic field in the conductive moving fluid.

The current induced in the liquid, detected by two electrodes, is directly proportional to the rate of flow.

3. A flowmeter in which changes in the flow of blood are measured through impedance to electromagnetic lines of force that are introduced across a stream of blood.

It has the great advantage that an intact blood vessel can be used.

A method of adjusting the electron beam in a television picture tube by varying the direct current flowing through the coils attached to the tube, and so, altering or changing the surrounding magnetic field: The electromagnetic focusing field is produced by sending an adjustable value of direct currents through a focusing coil mounted on the neck of the tube.

A form of energy which produces all the interactions between charged particles; such as, electricity, magnetism, chemical reactions, etc.

Electromagnetic force stops solids from falling apart, and acts between all particles with electric charges.

The elementary particle which is the carrier for the electromagnetic force is the photon.

A horn-shaped antenna structure which provides highly directional radiation of radio waves in the 100 megahertz or higher frequency range.

Signal power is fed to the horn by a waveguide or an exciting dipole or loop at the input end of the horn.

Adverse medical symptoms said to be caused by exposure to a physical field produced by moving electrically charged objects or physical properties of matter that causes it to experience a force when near other electrically charged material: "Research has indicated that those who suffer from electromagnetic hypersensitivity have symptoms that are caused by obscure or unknown sources including environmental intolerance attributed to electromagnetic fields (IEI-EMF) or electromagnetic hypersensitivity (EHS), which is also referred to as electrohypersensitivity, electrosensitivity, and electrical sensitivity."

"Those who claim to suffer from electromagnetic hypersensitivity report having headaches, fatigue, stress, sleep disturbances, skin symptoms like being stuck with needles, burning sensations and rashes, pains and aches in the muscles, and other health problems."

1. Generation of an electromotive force, in an insulated conductor moving in an electromagnetic field, or in a fixed conductor in a moving magnetic field.
2. The production of electric current in a circuit when it is passed through a changing magnetic field.
3. Voltage produced in a coil as a result of the relative motion between the coil and magnetic lines of force; such as, flux linkages passing through the coil changes.
4. The production of an electromotive force in a circuit by the variation of the magnetic field with which the circuit is connected.
5. The generation of an electromotive force by changing the magnetic flux through a closed loop circuit, or by moving a conductor across the magnetic field.

This principle is the basis for the electric generator and electric motor.

1. The characteristic delay of a current response in an electric circuit as it reaches its maximum or zero value after the source voltage is applied or removed.
2. Characteristic delay of a current in an electric circuit in reaching its maximum value, or in returning to zero, after the source voltage has been removed or applied.

1. A long-range force involving the electric and magnetic properties of elementary particles.
2. The interaction caused by elementary particles that results from the coupling of charge to the electromagnetic field.
3. The interaction due to electric charge; this includes magnetic effects that have to do with moving electric charges.
4. An interaction between charged elementary particles which is intermediate in strength between the strong and weak interactions.

1. Interference in a circuit caused by the radiation of an electric or magnetic field or the operation of a nearby electric motor; for example, the disturbance on a television set.
2. The harmful impairment of a desired electromagnetic signal by an electromagnetic disturbance.
3. Electromagnetic phenomena which, either directly or indirectly, can contribute to a degradation in the performance of an electronic receiver or system.

The terms radio interference, radio-frequency interference, noise, emi, and rfi have all been used at various times in reference to the same definition context.

4. An electrical, or electromagnetic, disturbance in a system caused by natural phenomena (lightning), low-frequency waves from electromechanical devices, or high-frequency waves from chips and other electronic devices; such as, radar, radio and TV signals, motors with brushes, and power lines.

Such electromagnetic disturbances can induce unwanted voltages in electronic circuits, damage components, and cause malfunctions.

Shields, filters, and transient suppressors are used in an effort to protect electronics from electromagnetic interferences.

1. An electron lens in which electron beams are focused by an electromagnetic field.
2. An electromagnet designed to produce a suitably shaped magnetic field for the focusing and deflection of electrons or other charged particles in electron optical instruments.
3. An electron lens consisting of a homogeneous axial electric field and a magnetic field, used in high-quality image tubes for high Modulation Transfer Function (MTF, a measurement of monitor sharpness) and small geometrical distortion requirements.

A security system that uses magnetic strips in objects that are read by a scanner in an antenna or a sensitizer/desensitizer.

1. An instrument used to measure and to record the movement rate of a vessel through water, having an electromagnetic sensing element that hangs from the vessel (craft designed for water transportation) and which produces a voltage that is directly proportional to the vessel's speed.
2. A log containing an electromagnetic sensing element extended below the hull of a vessel or ship.

This device produces a voltage directly proportional to the speed through the water.

1. A system that measures and records electromagnetic currents within a formation that is being drilled.
2. A method of well logging in which a transmitting coil sets up an alternating electromagnetic field, and a receiver coil, placed in the drill hole above the transmitter coil, that measures the secondary electromagnetic field induced by the resulting eddy currents within the formation.

1. The mass of a moving charge whose kinetic energy appears to account for the discrepancy between the total field energy and the field energy of a purely static electric field.
2. The contribution to the mass of an object from its electric and magnetic field energy.

1. An area or surface that is capable of reflecting electromagnetic waves.
2. A surface or a region capable of reflecting radio waves; such as, one of the ionized layers in the upper atmosphere.

1. The process of mixing molten metals or alloys by applying an electromagnetic field to produce eddies (movements in streams of fluids in which the currents double back on themselves causing miniature whirlpools).
2. The mixing of molten alloys by exposing the melt to a strong magnetic field while passing direct electrical current between electrodes at opposite ends of the crucible.

The stirring action results from an interaction of the magnetic field of the current-carrying molten alloy with the external transverse magnetic field.

1. A measure of the magnetic strength of a magnet or a current-carrying coil, expressed as the torque produced when the magnet or coil is set with its axis perpendicular to unit magnetic flux density which is measured in ampere meters squared.
2. The magnetic moment of a current-carrying coil, equal to the product of the current, the number of turns, and the area of the coil.
3. The vector magnetic moment of a current-carrying coil, equal to the product of the current, the number of turns, and the area of the coil.

The direction is given by the right-hand rule (right hand rule) or hand rule, which refers to a current-carrying wire where the rule is that if the fingers of the right hand are placed around the wire so that the thumb points in the direction of current flow, the fingers will be pointing in the direction of the magnetic field produced by the wire.

1. Noise in a communications system resulting from undesired electromagnetic radiation.
2. Any undesired electromagnetic disturbance.

1. An oscillograph that records signal waveforms by means of a moving-coil galvanometer or it is also known as a device for recording the wave-forms of changing currents, voltages, or any other quantity that can be translated into electric energy; such as, sound waves.
2. An oscillograph in which the recording mechanism is controlled by a moving-coil galvanometer; such as, a direct-writing recorder or a light-beam oscillograph (device for making a record of the wave forms of fluctuating voltages or currents).

The term electromagnetic is used to describe the combined electric and magnetic fields which are associated with movements of electrons through conductors.

The process includes the combined electrical and magnetic effects exhibited by and used by equipment, apparatus, and instruments; and, in terms of radiation, to describe the radiation which is associated with a periodically varying electric and magnetic field that is traveling at the speed of light; such as, light waves, radio waves, X-rays, gamma radiation, etc.

A transverse electric wave, transverse electromagnetic wave, or transverse magnetic wave.

A transverse electric wave and a transverse magnetic wave are electromagnetic waves in which the magnetic field vectors are every where perpendicular to the directions of propagation.

The effects of electromagnetic interference produced by human-made apparatus.

The seriousness of this interference ranges from annoying interference that affects a radio or television channel to interference which causes failure of an important communication channel or a cardiac pacemaker.

1. The electrostatic scalar potential plus the magnetic vector potential.
2. A collective name for a scalar potential, which reduces to the electrostatic potential in a time-independent system, and the vector potential for the magnetic field.

The electric and magnetic fields can be written in terms of these potentials.

1. Any form of rocket propulsion possessing both magnetic and electric properties; especially, one in which the propellant is accelerated by an electromagnetic field.

Specifically, such power in a flight vehicle generated by the electromagnetic acceleration of a plasma fluid.

2. Motive power for flight vehicles produced by electromagnetic acceleration of a plasma fluid.

1. A broadband, high-intensity, and short-duration burst of electromagnetic energy resulting from a nuclear explosion.
2. An electromagnetic reaction of large magnitude resulting from a thermonuclear explosion.
3. The pulse of electromagnetic radiation generated by a large thermonuclear explosion.
4. A powerful form of radiation released by a nuclear explosion, which has the effect of disrupting or disabling the electronically operated missile systems of a country.

1. A device that moves conducive liquid through a pipe by sending current through the liquid.

Used in a nuclear reactor cooling system for liquid alkali metal circulation.

2. A pump in which a conductive liquid is made to move through a pipe by sending a large current transversely through the liquid.

Such a current reacts with a magnetic field which is at right angles to the pipe and to the current flow in order to move the current-carrying liquid conductor just as a solid conductor is moved in an electric motor.

1. The emission and propagation of radiation associated with a periodically varying electric and magnetic field traveling at the speed of light.

Types include gamma radiation, X-rays, ultraviolet, visible, and infrared radiation, and radar and radio waves.

2. Radiation that is produced with a combination of magnetic and electric forces.

It exists as a continuous spectrum of radiation, from that with the highest energy level and the shortest wavelength (gamma rays) to that with the lowest energy and longest wavelength (long radio waves).

All forms of electromagnetic radiation travel at the speed of light.

Light, radio waves, and X-rays are forms of electromagnetic radiation. Almost all of our knowledge of extraterrestrial objects comes from emitted or reflected electromagnetic radiation (visible light or radio waves).

1. The emission and propagation of radiation associated with a periodically varying electric and magnetic field traveling at the speed of light, including gamma gray X-rays, and ultraviolet, light, infrared, and radio waves.
2. A reconnaissance activity for the purpose of locating and identifying potentially hostile transmitters of electromagnetic radiation, including radar, communication, missile-guidance, and navigation-aid equipment.

Identification generally includes determination of frequency, type of modulation, pulse data, antenna characteristics, and bearing to the transmitter.

1. A switch that opens and closes contacts by the action of an electromagnetic element.
2. A relay in which current flow through a coil produces a magnetic field that results in contact actuation.
3. A device that opens or closes contacts by settling "moving" contacts against "fixed" contacts when current passes through an electromagnet.

The electric current sets up a magnetic attraction between the core of the electromagnet and a hinged arm to the tip of which is attached the "moving" contact.

The movement of the arm towards the core of the electromagnet brings "moving" and "fixed" contacts together.

When an electric current is withdrawn, a spring returns the arm to to its original position and the contacts separate.

The repelling action between like poles of electromagnets.

1. A rocket that is accelerated by means of a plasma engine or an electrical-reaction engine in which magnetically accelerated plasma is used as the propellant.
2. An engine for space travel in which neutral plasma is accelerated and directed by external magnetic fields that interact with the magnetic field produced by electric current flow through the plasma.

The term plasma in these definitions refers to a gas-like state of matter consisting of positively charged ions, free electrons, and neutral particles.

Plasma is found in the stars, the sun, the solar wind, in lightning, and in fire.

An illness caused by radiation coming from cell phones, microwave or cell phone towers, radar, satellite, infrared, Wifi, GPS, RFID tags, computers, power lines, and other electrical equipment: "Individuals who are badly affected with EMF sensitivity suffer with headaches, insomnia, irritability, behavior disorders, autism, nerve and/or muscle pain, leukemia, tumors or cancer, heart attacks and other ailments."

"Certain population groups that have a tendency to suffer from elecromagnetic sensitivities include children, the elderly, and people with other illnesses."

"EMF Sensitivity is a highly controversial field of medicine; so, finding treatment for this illness is difficult, if not impossible, apparently because medical authorities do not consider electromagnetic fields a cause of the sicknesses as claimed by patients."

The separation of ions of varying mass by a combination of electric and magnetic fields.

In the most common application, an isotopic mixture of ions is produced by either electron bombardment of a gas or thermionic emission.

The ionized particles are accelerated and collimated (adjusted the line of sight) into a beam by a system of electrodes, and the beam is projected into a magnetic field where the paths of the ions depend on their mass-to-charge ratio.

1. An instrument that separates ions of different mass by passing them through a combination of electric and magnetic fields.
2. A device in which ions of varying mass are separated by a combination of electric and magnetic fields.

A metal screen or enclosure placed around circuits to reduce the effects of both electric and magnetic fields.

Electromagnetic fields are caused by motors, generators, relays, or devices whose operation dempends on alternating fields.

Shielding is achieved by a reflection or absorption of fields while reflection occurs at the surface, and it is not usually affected by shield thickness.

Absorption, however, occurs within the shield and it is highly dependent on the thickness of the shield.

1. A means of preventing two circuits from electromagnetically coupling by placing at lest one of the circuits in a grounded enclosure of magnetic conductive material.
2. A process, similar to electrostatic or magnetostatic shielding, for suppressing changing magnetic fields or electromagnetic radiation at a device.
3. Electromagnetic shielding is the process of limiting the penetration of electromagnetic fields into a space, by blocking them with a barrier made of conductive material that has the property of conducting an electric current.

1. An intense electromagnetic wave resulting from the coincidence of several waves of different velocities in a nonlinear dispersive medium.
2. An electromagnetic wave of significant intensity that results when waves with different intensities propagate with different velocities in a nonlinear optical medium, and faster-traveling waves from a pulse of light catch up with preceding, slower traveling waves.

1. The ordered sequence of all known forms of electromagnetic radiations, extending from the shortest cosmic rays through gamma rays, X-rays, ultraviolet radiation, visible radiation, and infrared radiation, and including microwaves and all other wavelengths of radio energy.
2. The entire range of different types of electromagnetic waves, extending from the very long, low-frequency radio waves, through infrared and light waves, to the very short, high-frequency cosmic rays and X-rays which can be generated physically.

This range of electromagnetic wavelengths extends almost from zero to infinity and includes the visible portion of the spectrum known as light.

3. A list, chart, graph, or diagram showing the relationships among all known types or range of electromagnetic radiation including the range of frequencies and wavelengths.
4. The total range of wavelengths, extending from the shortest to the longest wavelength or conversely, that can be generated physically.

This range of electromagnetic wavelengths extends practically from zero to infinity and includes the visible portion of the spectrum known as light.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Microphones in which the voltages are varied by an electromagnet; such as, ribbon or velocity microphones, dynamic or moving-coil microphones, and reluctance or moving-vane microphones.

• Ribbon or velocity microphones are those in which electric output depends on the velocity of the air particles that form a sound wave; examples are a hot-wire microphone and a ribbon microphone in which the conductor is a thin ribbon of aluminum alloy moving perpendicularly in a magnetic field. It is strongly directional and can be used to reduce unwanted side noise.
• Dynamic or moving-coil microphones consist of moving-conductor microphones in which the flexible diaphragms are attached to a coil positioned in the fixed magnetic fields of a permanent magnet.
• Reluctance or moving-vane microphones consist of diaphragms acted upon by sound waves that are connected to armatures which vary the reluctance in magnetic fields each of which is surrounded by a coil.

1. A clock which uses electronic circuits to count the number of oscillations (movements going backward and forward) in quartz crystal to determine the timekeeping impulses that activate a digital display.
2. A clock in which the timekeeping impulse is provided by the oscillations (alternating current and associated electric and magnetic fields) of a tiny tuning fork attached to an electronic circuit.

1. A division of electronic warfare in which actions are taken to interfere with a military enemy's use of the electromagnetic or a range of electromagnetic radiation or waves, used in military air defenses and interceptions.
2. The disruption of the operation of a military enemy's equipment; as by jamming radio or radar signals.
3. A military offensive or defensive tactic or device using electronic and reflecting apparatuses (apparatus or systems allowing certain functions) to reduce the military effectiveness of enemy equipment involving electromagnetic radiation; such as, guidance, radar, communication, or other radio-wave devices.