Modern amplifier equipment still labels the input that accepts the output from a modern magnetic pickup cartridge as the " phono " input, abbreviated from " phonograph ". Boy and phonograph

* A search-coil magnetometer with nonlinear amplifier to measure the Earth's, Moon's and interplanetary magnetic field.

Because it can be difficult to hear an acoustic bass guitar without an amplifier, even in settings with other acoustic instruments, most acoustic basses have pickups, either magnetic or piezoelectric or both, so that they can be amplified with a bass amp.

* Saturable Cored Reactor, a type of magnetic amplifier

# REDIRECT magnetic amplifier

It was in the mid -' 50s, while working as an amplifier designer at Gibson Guitars, that Lover figured out how to wire two coils electrically out of phase and with reversed magnetic polarities.

The magnetic amplifier ( colloquially known as a " mag amp ") is an electromagnetic device for amplifying electrical signals.

The magnetic amplifier was invented early in the 20th century, and was used as an alternative to vacuum tube amplifiers where robustness and high current capacity were required.

The magnetic amplifier was most prominent in power control and low-frequency signal applications from 1947 to about 1957, when the transistor began to supplant it.

The magnetic amplifier has now been largely superseded by the transistor-based amplifier, except in a few safety critical, high reliability or extremely demanding applications.

The magnetic amplifier is a static device with no moving parts.

The windings of a magnetic amplifier have a higher tolerance to momentary overloads than comparable solid-state devices.

The magnetic amplifier is also used as a transducer in applications such as current measurement and the flux gate compass.

Frequency response of a high gain amplifier is limited to about one-tenth the excitation frequency, although this is often mitigated by exciting magnetic amplifiers with currents at higher than utility frequency.

A saturable reactor, illustrating the principle of a magnetic amplifier

For controlled saturation characteristics the magnetic amplifier employs core materials that have been designed to have a specific B-H curve shape that is highly rectangular, in contrast to the slowly-tapering B-H curve of softly saturating core materials that are often used in normal transformers.

The typical magnetic amplifier consists of two physically separate but similar transformer magnetic cores, each of which has two windings-a control winding and an AC winding.

A magnetic amplifier was used as voice modulator for a 2 kilowatt Alexanderson alternator, and magnetic amplifiers were used in the keying circuits of large high-frequency alternators used for radio communications.

E. F. W. Alexanderson of the General Electric Company applied for his magnetic amplifier patent in 1912 and was responsible for developed a system of transoceanic radio communications, using continuous wave transmission over great distances.

1 " described an amplifier for telephone signals that used a magnetic field to modulate an arc in a mercury rectifier tube.

Chapter 8, is entitled `` On Magnetism '' and in it are included such remarks as, `` One has always been tempted to compare the magnetic forces with the electrical forces.

The form of galvanic activity is halfway between the magnetic form and the electrical form.

The pressure gradient producing the jet is due to the nature of the magnetic field in the arc ( rapid decrease of current density from cathode to the anode ).

A proton magnetic resonance study of polycrystalline Af as a function of magnetic field and temperature is presented.

An electrostatic system suffers generally from image plane curvature leading to defocusing in the peripheral image region if a flat viewing screen ( or interstage coupler ) is utilized, while a magnetic system requires accurate adjustment of the solenoid, which is heavy and bulky.

The conversion to magnetic tape is not yet completed, he said, and added Field's long service in state government and welfare employ gave him familiarity with the welfare program.

The magnetic quantum number,, describes the magnetic moment of an electron in an arbitrary direction, and is also always an integer.

In September of 1820, Ampère ’ s friend and eventual eulogist François Arago showed the members of the French Academy of Sciences the surprising discovery of Danish physicist Hans Christian Ørsted that a magnetic needle is deflected by an adjacent electric current.

One technique used to reach very low temperatures ( thousandths and even millionths of a degree above absolute zero ) is adiabatic demagnetisation, where the change in magnetic field on a magnetic material is used to provide adiabatic cooling.

Scientists dismiss these mechanisms as implausible since, for example, the magnetic field, when measured from earth, of a large but distant planet such as Jupiter is far smaller than that produced by ordinary household appliances.

In retrospect the name change was unfortunate, not only because the Greek roots alone do not reveal the anode's function any more, but more importantly because, as we now know, the Earth's magnetic field direction on which the " anode " term is based is subject to reversals whereas the current direction convention on which the " eisode " term was based has no reason to change in the future.

An alternating magnetic field is applied at the atomizer ( graphite furnace ) to split the absorption line into three components, the π component, which remains at the same position as the original absorption line, and two σ components, which are moved to higher and lower wavelengths, respectively ( see Zeeman Effect ).

Total absorption is measured without magnetic field and background absorption with the magnetic field on.

The advantage of this technique is that total and background absorption are measured with the same emission profile of the same lamp, so that any kind of background, including background with fine structure can be corrected accurately, unless the molecule responsible for the background is also affected by the magnetic field ; the disadvantage is the increased complexity of the spectrometer.

Alioth has a relatively weak magnetic field, 15 times weaker than α CVn, but it is still 100 times stronger than that of the Earth.

Sakharov, in association with Igor Tamm, proposed confining extremely hot ionized plasma by torus shaped magnetic fields for controlling thermonuclear fusion that led to the development of the tokamak device.

Gray also built a simple loudspeaker device into later models, which consisted of a diaphragm vibrating in a magnetic field.

He designed the first instruments used in satellites to measure cosmic radiation and ozone, and in 1951 or 1952 designed the MOUSE (" Minimal Orbital Unmanned Satellite, Earth "), a proposed satellite that would contain Geiger counters for measuring cosmic rays, photo cells for scanning the Earth, telemetry electronics for sending data back to Earth, a magnetic data storage device, and rudimentary solar energy cells.

* Nonlinearity: If the current through a ferromagnetic core coil is high enough that the magnetic core saturates, the inductance will not remain constant but will change with the current through the device.

An MRI scanner is a device in which the patient lies within a large, powerful magnet where the magnetic field is used to align the magnetization of some atomic nuclei in the body, and radio frequency fields to systematically alter the alignment of this magnetization.

A device that stores computer data on magnetic tape is a tape drive ( tape unit, streamer ).

At the Jülich Institute of Neurosciences and Biophysics, the world's largest PET / MRI device began operation in April 2009: a 9. 4-tesla magnetic resonance tomograph ( MRT ) combined with a positron emission tomograph ( PET ).

A stellarator is a device used to confine a hot plasma with magnetic fields in order to sustain a controlled nuclear fusion reaction.

Unlike a videocassette recorder ( VCR ), which uses removable magnetic tape cartridges, a TiVo DVR stores television programs on an internal hard drive that can only be removed by disassembling the device.

A tape drive is a data storage device that reads and writes data on a magnetic tape.

A tokamak is a device using a magnetic field to confine a plasma in the shape of a torus.

A radial magnetic field of a hundred gauss ( about 100 – 300 G, 0. 01 – 0. 03 T ) is used to confine the electrons, where the combination of the radial magnetic field and axial electric field cause the electrons to drift azimuthally, forming the Hall current from which the device gets its name.

The magnetic compass was first invented as a device for divination as early as the Chinese Han Dynasty.

The IPL device is usually a disk drive, but exactly the same procedure is also used to IPL from other input-type devices, such as tape drives, or even card readers, in a device-independent manner, allowing, for example, the installation of an operating system on a brand-new computer from an OS initial distribution magnetic tape ( for disk controllers, the </ tt > 02h </ tt > command also causes the selected device to seek to cylinder < tt > 0000h </ tt >, head < tt > 0000h </ tt >, and to search for record </ tt > 01h </ tt >, thereby also simulating a stand-alone seek command, </ tt > 07h </ tt >, and a search ID equal command, </ tt > 31h </ tt >; seeks and searches are not simulated by tape and card controllers ).

Inductive ( magnetic ) and capacitive ( electric ) field strengths are near-field effects, and are only important if the device under test ( DUT ) is designed for location close to other electrical equipment.

Effects of a HEMP device depend on a very large number of factors, including the altitude of the detonation, energy yield, gamma ray output, interactions with the Earth's magnetic field, and electromagnetic shielding of targets.

Hard sectoring in a magnetic or optical data storage device is a form of sectoring which uses a physical mark or hole in the recording medium to reference sector locations.

It has been suggested, controversially, that the Vikings exploited a similar device ( the " sunstone ") in their extensive expeditions across the North Atlantic in the 9th – 11th centuries, before the arrival of the magnetic compass in Europe in the 12th century.

The spiraling of electrons in a cylindrical vacuum chamber within a transverse magnetic field is also employed in the magnetron, a device for producing high frequency radio waves ( microwaves ).

A SQUID ( for superconducting quantum interference device ) is a very sensitive magnetometer used to measure extremely subtle magnetic fields, based on superconducting loops containing Josephson junctions.

It is for this reason that a patient with the device installed cannot be tested with the use of an MRI, which is a magnetic imaging device.