Electromagnets are used in many situations where a rapidly or easily variable magnetic field is desired. Many of these applications involve deflection of charged particle beams; the cathode ray tube and mass spectrometer fall into this category. Other devices cause electromagnetic fields to interact with fields from permanent magnets and produce forces. Electromagnetic actuators take advantage of the fact that, if the core of a solenoid is displaced toward one end of the coil, a force will occur tending to push the core farther in tha ...

See also:

Electromagnet, Electromagnet - Introduction, Electromagnet - Electromagnets and permanent magnets, Electromagnet - Devices that use electromagnets, Electromagnet - Force on ferromagnetic materials

Read more here: » Electromagnet: Encyclopedia II - Electromagnet - Devices that use electromagnets

See also:

Electromagnet, Electromagnet - Introduction, Electromagnet - Electromagnets and permanent magnets, Electromagnet - Devices that use electromagnets, Electromagnet - Force on ferromagnetic materials

Read more here: » Electromagnet: Encyclopedia II - Electromagnet - Electromagnets and permanent magnets

The simplest type of electromagnet is a coiled piece of wire. A coil forming the shape of a straight tube (similar to a corkscrew) is called a solenoid; a solenoid that is bent so that the ends meet is a toroid. Much stronger magnetic fields can be produced if a "core" of paramagnetic or ferromagnetic material (commonly iron) is placed inside the coil. The field produced by the coil causes the iron to magnetize and generate a field of its own. This field can be hundreds or thousands o ...

See also:

Electromagnet, Electromagnet - Introduction, Electromagnet - Electromagnets and permanent magnets, Electromagnet - Devices that use electromagnets, Electromagnet - Force on ferromagnetic materials

Read more here: » Electromagnet: Encyclopedia II - Electromagnet - Introduction

Crystals are tools that augment the flow of energy. They are like magnifying glasses, enhancing that which lies behind them (our thoughts, feelings, intentions and desires). This applies not only to desirable energy, however, but to all energy, both positive and negative. Through conscious use of crystals as tools, we can enhance anything we undertake. Quartz crystals have electromagnetic properties, hence their use in a lot of electrical devices. The human energy field is also electric (electromagnetic), and crystals can similarly enhance human energies.

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An X-ray microscope uses electromagnetic radiation in the soft X-ray band to produce images of very small objects. Unlike visible light microscopes, X-rays do not reflect or refract easily, and they are invisible to the human eye. Therefore the basic process of an X-ray microscope is to expose film or use a charge-coupled device (CCD) detector to detect X-rays that pass through the specimen, rather than light which bounces off the specimen. Early X-ray microscopes by Kirkpatrick and Baez used grazing-incidence reflective optics ...

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Because electromagnetic radiation such as normal radio communication cannot travel through thick conductors such as salt water, communication with submarines when they are submerged is a difficult technological task which requires specific techniques and devices. In many cases, the obvious solution is to surface and raise an antenna above the water surface to use standard technology. This is not sufficient, however, for nuclear-powered submarines. These vessels, developed during the Cold War by the major military powers, are ca ...

Including:

Communication with submarines - Acoustic transmission Communication with submarines - Very low frequency Communication with submarines - Extremely low frequency Communication with submarines - Standard radio technology

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A Cochlear implant is a device implanted in the inner ear to restore hearing by stimulating nerves inside the cochlea. Current devices are used with an external sound processor, the size of a cell phone. The sound processor converts the sound into electrical signals that run through a thin cable to a pad placed behind the external ear over a receiving pad under the skin. The signals are transmitted through the skin by electromagnetic induction and through an internal cable to electrodes inside the cochlea. The cochlear implant can giv ...

Including:

Cochlear implant - Who can use a Cochlear Implant? Cochlear implant - The Device
Cochlear implant - Processing Cochlear implant - Transmitter Cochlear implant - Receiver Cochlear implant - Electrode array Cochlear implant - Programming the Speech Processor Cochlear implant - Current Devices
Cochlear implant - Objections to use
Cochlear implant - The Older Patient Cochlear implant - Children

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Electricity is a property of matter that results from the presence of electric charge. Together with magnetism, it constitutes the fundamental interaction known as electromagnetism. Electricity is responsible for many well-known physical phenomena such as lightning, electric fields and electric currents, and is put to use in industrial applications such as electronics and electric power. Electricity - Concepts in electricity. In casual usage, the term electricity is applied to several related concept ...

Including:

Electricity - Concepts in electricity Electricity - History
Electricity - Ancient Electricity - Modern
Electricity - Electric charge Electricity - Electric field Electricity - Electric potential Electricity - Electric current Electricity - Electrical energy Electricity - Electric power Electricity - SI electricity units
Electricity - Devices Electricity - Engineering Electricity - Safety Electricity - Electrical phenomena in nature

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In quantum optics, shot noise are caused by the fluctations of detected photons, therefore again a consequence of discretisation (of the energy in the electromagnetic field in this case). Shot noise is a main part of quantum noise. Shot noise is not only measurable in measurements at the few photons level using photo-multipliers, but also at stronger light intensities measured by photodiodes when using high temporal resolution oscilloscopes. As the photo-current is linear to the light intensity (photon number), the fluctuations of the electromagnetic field are usuall ...

See also:

Shot noise, Shot noise - Electronic devices, Shot noise - Quantum Optics, Shot noise - Space charge

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Devices used for scaring birds away from aircraft near airfields by microwave hearing and induction of vertigo exist (Kreithen ML. Patent #5774088 “Method and system for warning birds of hazards” USPTO granted 6/30/98). But the majority of applications are dedicated for direct machine to brain wireless communication, with numerous patents. ...

See also:

Microwave auditory effect, Microwave auditory effect - Natural sources of electromagnetic perception, Microwave auditory effect - Full spectrum electromagnetic perception, Microwave auditory effect - Primary Cold War-era research in the US, Microwave auditory effect - Peaceful applications, Microwave auditory effect - Weaponization, Microwave auditory effect - Patented applications

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Many plastics are birefringent, because their molecules are 'frozen' in an stretched conformation when the plastic is moulded or extruded. For example, cellophane is a cheap birefringent material. Birefringent materials are used in many devices which manipulate the polarization of light, such as wave plates, polarizing prisms, and Lyot filters. There are many birefringent crystals: birefringence was first described in calcite crystals by the Danish scientist Rasmus Bartholin in 1669. The refractive indices of several (uniaxial) birefri ...

See also:

Birefringence, Birefringence - Electromagnetic waves in an anisotropic material, Birefringence - Examples of birefringent materials, Birefringence - Biaxial birefringence, Birefringence - Measuring birefringence, Birefringence - Birefringence in fiber optics

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The first working sonar was built by Reginald Fessenden in the United States in 1914. It used an electromagnetic moving-coil oscillator that would emit a low frequency noise, then switch to listening mode to receive the echoes. Because of its crude technology, it could not precisely determine direction. The first device to be called a "hydrophone" was developed when the technology matured, and used ultrasonic waves, which would provide for higher overall acoustic output, as well as increasing detection. The ultrasonic waves were produ ...

See also:

Hydrophone, Hydrophone - History, Hydrophone - Directional hydrophones, Hydrophone - Damping and reflecting, Hydrophone - Arrays, Hydrophone - Geophysics

Read more here: » Hydrophone: Encyclopedia II - Hydrophone - History

Many plastics are birefringent, because their molecules are 'frozen' in an stretched conformation when the plastic is moulded or extruded. For example, cellophane is a cheap birefringent material. Birefringent materials are used in many devices which manipulate the polarization of light, such as wave plates, polarizing prisms, and Lyot filters. There are many birefringent crystals: birefringence was first described i ...

See also:

Birefringence, Birefringence - Electromagnetic waves in an anisotropic material, Birefringence - Examples of birefringent materials, Birefringence - Biaxial birefringence, Birefringence - Measuring birefringence, Birefringence - Birefringence in fiber optics

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Electronic devices are used to perform a wide variety of tasks. The main uses of electronic circuits are the controlling, processing and distribution of information, and the conversion and distribution of electric power. Both of these uses involve the creation or detection of electromagnetic fields and electric currents. While electrical energy had been used for some time to transmit data over telegraphs and telephones, the development of electronics truly began in earnest with the advent of radio. ...

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Electronics, Electronics - Electronic devices today, Electronics - CAD/CAM of electronic circuits, Electronics - Electronic systems, Electronics - Electronic test equipment, Electronics - Electronic components, Electronics - Analog circuits, Electronics - Digital circuits, Electronics - Mixed-signal circuits, Electronics - Heat dissipation, Electronics - Noise, Electronics - Electronics theory

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The meaning of the term maser has changed slightly since its introduction. Initially the acronym was universally given as "microwave amplification by stimulated emission of radiation," which described devices which emitted in the microwave region of the electromagnetic spectrum. The principle of stimulated emission has since been extended to more devices and frequencies, and so the original acronym is sometimes modified, as suggested by Charles H. Townes [3], to "molecular amplification ...

See also:

Maser, Maser - History, Maser - Technology, Maser - Some common types of masers, Maser - Astrophysical Masers, Maser - Uses, Maser - Hydrogen maser, Maser - Terminology, Maser - Masers in science fiction

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Square waves are universally encountered in digital switching circuits and are naturally generated by binary (two-level) logic devices. They are used as timing references or "clock signals", because their fast transitions are suitable for triggering synchronous logic circuits at precisely determined intervals. However, as the frequency-domain graph above shows, square waves contain a wide range of harmonics; these can generate electromagnetic radiation or pulses of current that interfere with other nearby circuits, causing noise or errors. T ...

See also:

Square wave, Square wave - Origins and uses, Square wave - Examining the square wave, Square wave - Characteristics of imperfect square waves, Square wave - Other definitions

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When fitting components together to carry electromagnetic signals, it is important to match impedance, which can be achieved with various matching devices. Failing to do so is known as impedance mismatch and results in signal loss and reflections. The existence of reflections allows the use of a time-domain reflectometer to locate mismatches in a transmission system. For example, a conventional radio frequency antenna for carrying broadcast television in North America was standardized to 300 ohms, using balanced, unshielded, flat wiri ...

See also:

Electrical impedance, Electrical impedance - AC steady state, Electrical impedance - Definition of impedance, Electrical impedance - Impedance of different devices, Electrical impedance - Resistor, Electrical impedance - Capacitor, Electrical impedance - Inductor, Electrical impedance - Reactance, Electrical impedance - Combining impedances, Electrical impedance - In series, Electrical impedance - In parallel, Electrical impedance - Circuits with general sources, Electrical impedance - Magnitude and phase of impedance, Electrical impedance - Peak phasor versus rms phasor, Electrical impedance - Matched impedances, Electrical impedance - Inverse quantities, Electrical impedance - Acoustic impedance, Electrical impedance - Data-transfer impedance, Electrical impedance - Application to physical devices

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The implant is surgically placed under the skin behind the ear. The basic parts of the device include: External: a microphone, a speech processor which selectively filters sound to prioritise audible speech and sends the electrical sound signals through a thin cable to the transmitter, a transmitter, which is a magnetic pad placed behind the external ear, and transmits the processed sound signals to the internal device by electromagnetic induction, ...

See also:

Cochlear implant, Cochlear implant - History, Cochlear implant - How the implant works, Cochlear implant - Processing, Cochlear implant - Transmitter, Cochlear implant - Receiver, Cochlear implant - Electrode array, Cochlear implant - Programming the speech processor, Cochlear implant - Who can use a cochlear implant?, Cochlear implant - Current devices, Cochlear implant - Objections to use, Cochlear implant - The Older Patient, Cochlear implant - Children, Cochlear implant - Cochlear implant in popular culture

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Every electric current produces a magnetic field. The magnetic field can be visualized as a pattern of circular field lines surrounding the wire. Electric current can be directly measured with a galvanometer, but this method involves breaking the circuit, which is sometimes inconvenient. Current can also be measured without breaking the circuit by detecting the magnetic field it creates. Devices used for this include ...

See also:

Current electricity, Current electricity - Relation between current and charge, Current electricity - Conventional current, Current electricity - The speed of an electric current, Current electricity - Current density, Current electricity - Electromagnetism, Current electricity - Ohm's law, Current electricity - Electrical safety

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International standard IEC 60364 distinguishes three families of earthing arrangements using the two-letter codes TN, TT, and IT. The first letter indicates the connection between earth and the power-supply equipment (generator or transformer): The second letter indicates the connection between earth and the electrical device being supplied: Earthing system - TN network. In a TN earthing system, one of the points in the generator or transformer is connected with ea ...

See also:

Earthing system, Earthing system - IEC nomenclature, Earthing system - TN network, Earthing system - TT network, Earthing system - IT network, Earthing system - Properties, Earthing system - Cost, Earthing system - Safety, Earthing system - Electromagnetic compatibility, Earthing system - Regulations, Earthing system - Application examples, Earthing system - Reference

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