SU892379A1 - Device for measuring magnetic field induction - Google Patents

Description

I

The invention relates to a measurement technique, in particular to magnetic field induction meters, and can be used in automation, control and monitoring circuits.

The closest to the proposed technical entity is a device for measuring the induction of a magnetic field, in which the sensitive element is designed as a unipolar field-effect transistor, the voltage on the load resistor of which varies in accordance with the magnitude of the induction of the measured magnetic field

However, in the absence of a magnetic field on the load resistor, there is some initial voltage. Therefore, in order to comply with the zero value of the magnetic field, the zero value of the voltage applied to the indicator, a circuit is necessary to compensate for the initial voltage across the load resistor. Except2

First, the unipolar field effect transistor has a substantial temperature dependence of the characteristics. Increasing temperature stability entails a complication of the circuit and design. All this complicates the design of the device, increases the power consumption, ee, dimensions and cost of construction and reduces its reliability.

The purpose of the invention is to increase the sensitivity.

This goal is achieved by the fact that in a device for measuring the induction of a magnetic gtol, containing a sensitive element with load

15 by collector resistors, the sensing element is designed as a balanced bipolar toroid magnetotransmission, which is a plate of semiconductor material

Claims (1)

20 with an emitter of minority carriers at one end, a base contact at the opposite end, and two electrically symmetric collectors of minority carriers located between them. The drawing shows the block diagram of the device for measuring the magnetic field induction. The device contains a bipolar balanced magnetotransistor 1, which is in a magnetic field with induction B, has a plate 2 of semiconductor material, an emitter 3 basic contact 4, two electrically symmetric collectors 5 and 6, load collector transistors 7 and 8, the difference of the voltage drops of which enters the indicator 9 (or the corresponding device) and the sources 10 and 11 of the power supply to the emitter and collector circuits. The device works as follows. In the absence of a magnetic field (), the collector currents 5 and 6 with equal load collector resistors 7 and 8 are the same, therefore, the difference is O, and on the indicator 9 the voltage is 0. When a magnetic field is applied to the magnetotransistor but the plane in which the collectors 5 and 6 are located, the emitter 3 and the base contact k, minor current carriers in the magnetotransistor plate 2, injected by the emitter 3, are deflected by the Lorentz forces and by the action of the Hall electric field to one of the collectors (in the case of the n-type plate material and in the direction of the magnetic field shown in the drawing, to the collector 5 and in the case of the p-type plate material to the collector 6). As a result, at the collector to which minority current carriers deviate, their concentration increases, and at the opposite collector it decreases, which leads to an increase in the current of the corresponding collector and a decrease in the current of the opposite collector. Moreover, the larger the magnitude of the magnetic field B, the stronger the minority carriers deviate, the greater the difference in the collector currents and, therefore, the longer the voltage difference across the load collector resistors 7 and 8, recorded by the indicator 9. Using balanced bipolar The magnetotransistor in the MOM device has the advantage that the deviation of minor current carriers occurs not only due to the Lorentz forces, but also due to the Hall’s electric field, the sensitivity of such a magnet otranzistorov to the magnetic field is higher than the sensitivity of unipolar field-effect transistors. In addition, the use of a balanced (bipolar magnetotransistor is equivalent to approximately double the sensitivity. The dimensions of magnetotransistor 1 are small, so the entire volume of plate 2 is almost uniform (it has, close to the electrophysical parameters). how are the conditions as close as possible during the entire process of manufacturing the magnetotransistor, therefore their characteristics are very close and have almost equal The change in time and temperature. As a result, the temporal and temperature stability of a balanced magnetotransistor is very high and significantly better than that of a unipolar field-effect transistor. The spatial resolution and sharpness of directionality, as in the case of using a unipolar field-effect transistor, have a balance The size of the active magnetotransistor is determined by the size of the active part (practically plate size, sensitivity, to the magnetic field and noise. Apparatus for measuring the induction of a magnetic field containing a sensitive element with load collector resistors, characterized in that, in order to increase the sensitivity, the sensitive element is designed as a balanced bipolar magnetotransistor, which is a plate of semiconductor material with an emitter of non-main current carriers one end, the base contact on the opposite end and two electrically symmetric non-basic collectors located between them current carriers. Sources of information taken into account in the examination 1. USSR author's certificate G 298905, cl. G 01 R 33/02, 1969