scholarly journals XII. A new current weigher and a determination of the electromotive force of the normal Weston cadmium cell

1908 ◽  
Vol 207 (413-426) ◽  
pp. 463-544 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic System ◽  
Electric Circuit ◽  
Secular Variations ◽  
System Of Units ◽  
Electro Magnetic ◽  
The Magnetic Field ◽  
A Current ◽  
Mutual Action

A Current can be measured absolutely in the electro-magnetic system of units either by means of the action of the current on a magnet, or of the current on a current. The former method has the disadvantage that at least two independent measurements are necessary. For example, in using an electro-magnetic balance, the strength of the magnet acted on by the electric circuit has to be determined, as well as the force exerted on the magnet by the circuit. In galvanometers, either of the sine or tangent type, the magnetic field produced by the electric circuit is compared with the earth’s horizontal field, the strength of which is determined independently. Further, as the strength of artificial magnets cannot be regarded as truly constant, and the earth’s field is subject to diurnal and secular variations, this class of measurement is not ideal. In the electrodynamic class of measurement the mutual action between two or more coils carrying current takes the form of a torque, as in electrodynamometers, or a direct force, as in current weighers. In electrodynamometers the torque may be measured with a bifilar suspension, the torsion of a wire or spring, or by means of a gravity balance. Current weigher measurements are almost always made by direct comparison with gravity, which is believed to be constant, and is known to a higher degree of accuracy than the strengths of any magnet or magnetic field that has yet been measured.

Design and Fabrication of a Micro-Actuator Based on Electromagnetic Membrane Device

2012 ◽  
Vol 488-489 ◽  
pp. 1451-1456
Author(s):  
Rong Hua Ma ◽  
Jian Hao Zhong
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Physical Size ◽  
Ac Power ◽  
Coil Structure ◽  
Electro Magnetic ◽  
Ndfeb Permanent Magnet ◽  
The Magnetic Field ◽  
A Current

The purpose of this study is to develop a micro electro-magnetic actuator manufactured by MEMS-based fabrication and electroplating techniques. This actuator presented a novel technique in the electromagnetic fabrication and smaller physical size than the traditional counterparts for micro actuators and provides a faster response time and lower cost. A micro coil structure is released from FeCl3 etchant and bonded on a thin film (Parafilm”M”, Pechiney Plastic Packaging Inc.) to achieve an actuator-membrane structure. When an external AC power is applied to a micro coil, a magnetic field is created to attract and repel through an NdFeB permanent magnet, and the displacement of the membrane is increased as a current of AC power. The results show the measured magnetic field intensity weakens as the distance between the coil and the Gauss meter probe increases. However, it is observed that the magnetic field intensity does not increase linearly with the number of series coils, which is due to the distance between series coils.

scholarly journals 3. An Electro-Magnetic Declinometer

1884 ◽  
Vol 12 ◽  
pp. 544-560 ◽  
Author(s):  
A. Tanakadaté ◽  
J. A. Ewing
Keyword(s):  
Magnetic Field ◽  
Electric Circuit ◽  
East And West ◽  
Electro Magnetic ◽  
Magnetic Meridian ◽  
Terrestrial Magnetic Field ◽  
A Current ◽  
Lines Of Force

The terrestrial magnetic field will in general be disturbed in the neighbourhood of an electric circuit; but if the circuit be a plane set at right angles to the terrestrial lines of force, the direction of the field will remain unchanged at all points in the plane of the circuit. To determine the magnetic meridian, we have only to place a plane circuit in such a direction that, when a current in the circuit is started and stopped, no change takes place in the position of a small magnet hung at a point in the plane of the circuit, and free to turn in azimuth. The plane of the circuit will then lie magnetically east and west.

scholarly journals The galvanometer constant of a circular coil of many windings

1935 ◽  
Vol 150 (871) ◽  
pp. 487-494
Keyword(s):  
Magnetic Field ◽  
Rectangular Channel ◽  
Number Of Layers ◽  
Circular Coil ◽  
Absolute Measure ◽  
The Mean ◽  
The Wire ◽  
The Magnetic Field ◽  
A Current

In a number of investigations the strength of the magnetic field at the centre of a circular coil of many turns due to a current in the coil is required. Among these may be mentioned the determination of the ampere in absolute measure by the method adopted by Rayleigh and Sidgwick. Let a be the mean radius of the coil, N the number of turns, 2 b and 2 c the axial and radial dimensions of the rectangular channel in which the coil is wound, d and d 0 the covered, α bare diameters of the wire, m the number of windings in a layer, and n the number of layers.

On the Configuration of the Magnetic Field of β CrB

1976 ◽  
Vol 32 ◽  
pp. 613-622
Author(s):  
I.A. Aslanov ◽  
Yu.S. Rustamov
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Radial Velocity ◽  
Magnetic Field Strength ◽  
Complex Shape ◽  
Rotation Period ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Secular Variations ◽  
The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

MAGNETIC FIELD IMPACT UPON TRIBOTECHNICAL CHARACTERISTICS OF PERMANENT CONNECTIONS IN RELATION TO FRICTION SHOCK ABSORBERS

2020 ◽  
Vol 2020 (10) ◽  
pp. 4-11
Author(s):  
Victor Tikhomirov ◽  
Aleksandr Gorlenko ◽  
Stanislav Volohov ◽  
Mikhail Izmerov
Keyword(s):  
Magnetic Field ◽  
Friction Factor ◽  
Physical Contact ◽  
Active Centers ◽  
Press Fit ◽  
Electro Magnetic Field ◽  
Investigation Methods ◽  
Electro Magnetic ◽  
The Impact ◽  
The Magnetic Field

The work purpose is the investigation of magnetic field impact upon properties of friction steel surfaces at fit stripping with tightness through manifested effects and their wear visually observed. On the spots of a real contact the magnetic field increases active centers, their amount and saturation with the time of dislocation outlet, and has an influence upon tribo-mating. The external electro-magnetic field promotes the increase of the number of active centers at the expense of dislocations outlet on the contact surface, and the increase of a physical contact area results in friction tie strengthening and growth of a friction factor. By the example of friction pairs of a spentonly unit in the suspension of coach cars there is given a substantiation of actuality and possibility for the creation of technical devices with the controlled factor of friction and the stability of effects achieved is also confirmed experimentally. Investigation methods: the fulfillment of laboratory physical experiments on the laboratory plant developed and patented on bush-rod samples inserted with the fit and tightness. The results of investigations and novelty: the impact of the magnetic field upon the value of a stripping force of a press fit with the guaranteed tightness is defined. Conclusion: there is a possibility to control a friction factor through the magnetic field impact upon a friction contact.

Study of MFM Application in Semiconductor Failure Analysis

2004 ◽  
Author(s):  
Way-Jam Chen ◽  
Lily Shiau ◽  
Ming-Ching Huang ◽  
Chia-Hsing Chao
Keyword(s):  
Magnetic Field ◽  
Failure Analysis ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Current Flow ◽  
Force Microscopy ◽  
The Magnetic Field ◽  
A Current

Abstract In this study we have investigated the magnetic field associated with a current flowing in a circuit using Magnetic Force Microscopy (MFM). The technique is able to identify the magnetic field associated with a current flow and has potential for failure analysis.

Sensor of Current or Magnetic Field Based on Magnetoresistance Effect in (La0.7Ca0.3)0.8Mn1.2O3 Manganite Film

2009 ◽  
Vol 154 ◽  
pp. 157-161 ◽  
Author(s):  
V.P. Dyakonov ◽  
S. Piechota ◽  
K. Piotrowski ◽  
A. Szewczyk ◽  
H. Szymczak ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Short Circuit ◽  
Operation Time ◽  
Electric Circuit ◽  
Current Sensor ◽  
Detectable Change ◽  
Magnetoresistance Effect ◽  
Manganite Film ◽  
Current Value ◽  
A Current

The main objective of the performed investigations was to enhance sensitivity of a current sensor to weak changes of magnetic field. New design of the sensor of current based on magnetoresistance effect – MRE (MRE = (RH - R0)/R0 , where RH is the resistance in magnetic field and R0 is the resistance without magnetic field) was developed. The sensor was produced in the form of an annular magnet with a gap, in which the (La0.7Sr0.3)0.8Мn1.2О3 manganite film possessing large negative MRE was inserted. Nominal current in a controllable electric circuit can change from a few tenths parts of ampere to a hundred of amperes. The limit detectable change of current value depends on the size of gap in the annular magnet. The operation time of sensor at current overload and short circuit is less than 0.3 sec. These magnetoresistors are thermally stable over the temperature range from (- 50 ° С) to (+ 50 ° С). Proposed sensors based on MRE can be applied in many electrical arrangements and devices.

Zum Rotations-Zeeman-Effekt in Dimethylketen / Molecular Zeeman Effect and the Determination of the Molecular g Values, Paramagnetic Susceptibilities, and Molecular Quadrupole Moments in Dimethylketene

1972 ◽  
Vol 27 (4) ◽  
pp. 597-600 ◽  
Author(s):  
D. Sutter ◽  
L. Charpentier ◽  
H. Dreizler
Keyword(s):  
Magnetic Field ◽  
Zeeman Effect ◽  
Microwave Spectrum ◽  
Quadrupole Moments ◽  
Selection Rules ◽  
Rotational Transitions ◽  
The Magnetic Field

Abstract The rotational Zeeman-Effect in the microwave spectrum of dimethylketene was investigated at fieldstrengths close to 22 kG. Only ΔJ= 1 rotational transitions with ΔM = ± 1 selection rules did show appreciable splittings due to the magnetic field. From the splittings the diagonal elements of the molecular gr-tensor were determined to be: gaa = ∓ 0.020(3) ; gbb = ∓ 0.0165(8) ; gcc= + 0.0126(5). (Only the relative signs of the g-values are obtained from the experiment). The susceptibility anisotropics were found to be close to zero.

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