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.
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.
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.
2. A cathode-ray tube in which electromagnetic deflection is used on the electron beam.
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.
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.
2. Electromagnetic configuration of an installation, including all significant radiators of energy.
2. The speed of the propagation of electromagnetic waves in a vacuum.
2. A coupling that exists between circuits when they are mutually affected by the same electromagnetic field.
When a flawed portion passes through the magnetizing coil, the magnetic flux drops.
2. Motions of charged particles; for example, in the ionosphere, that are giving rise to electric and magnetic fields.
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.
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.
2. An electromagnetic development, usually impulsive, that is superimposed on a desired signal.
The disturbance may be random or periodic.
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.
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).
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.
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.
Signal power is fed to the horn by a waveguide or an exciting dipole or loop at the input end of the horn.
"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."
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.
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.
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.
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.
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.
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.
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.
2. The contribution to the mass of an object from its electric and magnetic field energy.
2. A surface or a region capable of reflecting radio waves; such as, one of the ionized layers in the upper atmosphere.
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.
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.
2. Any undesired electromagnetic disturbance.
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 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 and a transverse magnetic wave are electromagnetic waves in which the magnetic field vectors are every where perpendicular to the directions of propagation.
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.
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.
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.
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.
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.
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).
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.
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.
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.
"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."
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.
2. A device in which ions of varying mass are separated by a combination of 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.
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.
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.
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.
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.
2. The tolerance of circuits and components to all sources of interfering electromagnetic energy.
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.
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.
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.
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.
2. A transverse wave associated with the transmission of electromagnetic energy.
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.
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.
This takes place when a circuit requires an alternating current to operate and a reed within the vibrator is alternately attracted to two electromagnets.
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.
2. Any device to transmit electromagnetic waves of desired frequencies while substantially reducing the strength of all of the other frequencies.
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.
- 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.
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.
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.
Such radiation results commonly from the acceleration of an electric charge, and is propagated in a vacuum at the speed of light.
2. The range of wavelengths, or frequencies, over which electromagnetic radiation is propagated.
The longest wavelengths, or lowest frequencies, are those of radio waves, and the shortest wavelengths are those of gamma rays.