In 1930, TC1 decided that the magnetic field strength (H) is of a different nature from the magnetic flux density (B), and took up the question of naming the units for these fields and related quantities, among them the integral of magnetic flux density.
(magnetic flux) is measured in webers (symbol: Wb) so that a flux density of 1 Wb/m 2 is 1 tesla. The SI unit of tesla is equivalent to (newton·second)/(coulomb·metre). In Gaussian-cgs units,
In the CGS system, the unit of the H-field is the oersted and the unit of the B‑field is the gauss. In the SI system, the unit ampere per meter (A/m), which is equivalent to newton/weber, is used for the H‑field and the unit of tesla is used for the B‑field.
The units for magnetic flux Φ, which is the integral of magnetic field over an area, are the weber (Wb) in the SI and the maxwell (Mx) in the cgs system. The conversion factor is 10 8, since flux is the integral of field over an area, area having the units of the square of distance, thus 10 4 (magnetic field conversion factor) times the square of 10 2 (linear distance conversion factor, i.e., centimetres per meter). 10 8 = 10 4 × (10 2 ) 2.
A sensitive DC SQUID magnetometer able to discriminate changes as small as one quantum, or about 2 Wb, is used to monitor the gyroscope. A precession, or tilt, in the orientation of the rotor causes the London moment magnetic field to shift relative to the housing. The moving field passes through a superconducting pickup loop fixed to the housing, inducing a small electric current. The current produces a voltage across a shunt resistance, which is resolved to spherical coordinates by a microprocessor. The system is designed to minimize Lorentz torque on the rotor.
) through a surface is the surface integral of the normal component of the magnetic field flux density B passing through that surface. The SI unit of magnetic flux is the weber (Wb) (in derived units: volt \cdot seconds), and the CGS unit is the maxwell. Magnetic flux is usually measured with a fluxmeter, which contains measuring coils and electronics, that evaluates the change of voltage in the measuring coils to calculate the measurement of magnetic flux.
When a charged particle—such as an electron—is placed in a magnetic field, it experiences a Lorentz force proportional to the strength of the field and the velocity at which it is traveling through it. This force is strongest when the direction of motion is perpendicular to the direction of the magnetic field; in this case the force :where q is the charge on the particle in coulombs, v the velocity it is traveling at (centimeters per second), and B the strength of the magnetic field (Wb/cm²). Note that centimeters are often used to measure length in the semiconductor industry, which is why they are used here instead of the SI units of meters.