A measure of the quantity of magnetism in a magnetic field.

Related Terms


A sensor that uses the Hall effect to measure magnetic field strength.


  1. A unit of length equal to 5.5 yards or 16.5 feet. Also called POLE, PERCH. 2. One of the imaginary slender soft iron bars which are assumed to be components or parameters of a craft’s magnetic field caused by magnetism induced in soft iron.


A material used to prevent, dissolve, or facilitate removal of oxides and other undesirable surface substances. Also, the measure of the quantity of magnetism, taking into account the strength and extent of the magnetic field.

Functions Of Fluxes

Continuity of grain structure across a soldered or welded joint can only be obtained if the metals are brought into atomic contact, and this is not possible if the metals are coated with oxide layers, grease, corrosion products or other surface films. Mechanical cleaning can only remove the bulk of such surface films, some form of chemical cleaning being necessary to complete the cleaning operation. Fluxes perform some or all of the following functions:

They chemically clean the surfaces to be joined,

They prevent the formation of new oxide layers during the heating cycle of the joining process,

They assist the filler metal to run freely into the joint, and

They assist the "wetting" process by which surfaces alloying occurs.


Iron or steel which is easily magnetized by induction, but loses its magnetism when the magnetic field is removed. The opposite is HARD IRON.


A device used to measure the intrinsic hysteresis loop of a sample of magnetic material.


Deviation of a magnetic compass due to transient magnetism caused by eddy currents set up by a changing number of lines of force through soft iron as the ship changes heading. Due to these eddy currents, the induced magnetism on a given heading does not arrive at its normal value until about 2 minutes after change to the heading. This error should not be confused with RETENTIVE ERROR.


A derived unit of magnetic flux in the International System of Units; it is that magnetic flux which, linking a circuit of one turn, would produce in it an electromotive force of 1 volt if it were reduced to zero at a uniform rate in 1 second.


A type of inclinometer that has a coil which rotates in the earth's field and in which a voltage is induced when the rotation axis does not coincide with the field direction; used to measure the dip angle of the earth's magnetic field. Also known as dip inductor; earth inductor compass; induction inclinometer.


A type of fluxmeter in which a light coil of wire is suspended in a magnetic field in such a way that it can rotate; the ends of the suspended coil are connected to a search coil of known area penetrated by the magnetic flux to be measured; the flux is determined from the rotation of the suspended coil when the search coil is moved.


The production of magnetic flux by supplying electric current to the field poles of a generator to create a variable magnetic field.

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