When the metal rotor blade passes through the gap, the magnetic flux is shunted and the induction on the microcircuit is zero. In addition, the Hall sensor is more expensive than a magnetoelectric and theoretically less reliable because it contains an electronic circuit, but large-scale production and development of technology minimize these factors. The main one is that which is inherent in any electronic circuit: the sensor is sensitive to electromagnetic interference arising in the power circuit (for the precautionary measures dictated by this circumstance, let us say below). The sensor has other advantages as well, but we will mention shortcomings. To control the electronics is a considerable plus. Third, the electrical signal from the sensor has, in the terminology of specialists, a rectangular shape: when turned on, it immediately dials a certain and constant value, and does not have the character of bursts. Secondly, and this is especially important, a change in the frequency of operation (in other words, engine speed) does not cause a shift in the measurement moment. Such a device has a number of undeniable advantages. Quantum Hall EffectĮven later, with the development of microelectronics, it was possible to make a miniature sensor containing everything you need - a permanent magnet and a chip with a sensitive element. For example, an abnormal Hall effect can be observed in samples with magnetization. Ī necessary condition for observing the anomalous Hall effect is a violation of invariance with respect to the time reversal in the system. The occurrence of a voltage (electric field) in a sample perpendicular to the direction of the current through the sample, observed in the absence of an applied constant magnetic field (that is, a phenomenon completely similar to the Hall effect, but observed without an external constant magnetic field) is called the anomalous Hall effect. tW251bGwsMSwxLDEsImNvbS5hcHAuYm9vay5BT1RMVkVXSVdQWEFYWUdNWiJd Wheel speed sensors of the Hall. For some metals (for example, such as lead, zinc, iron, cobalt, tungsten), a positive sign is observed in strong fields, which is explained in the semiclassical and quantum theories of a rigid body. In this approximation, the sign of the Hall constant depends on the sign of charge carriers, which allows one to determine their type for a large number of metals. ThenĬoefficient proportionality between and called the coefficient (or constant ) of the Hall. Where - concentration of charge carriers. Charging will continue as long as the resulting electric field of charges does not compensate for the magnetic component of the Lorentz force:Įlectron velocity can be expressed in terms of current density:
Thus, the Lorentz force will lead to the accumulation of a negative charge near one face of the bar, and a positive charge near the opposite.
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