SU954906A1 - Device for creating weak uniform magnetic field - Google Patents

Description

one

The invention relates to magnetic measurements, in particular, to techniques for creating weak uniform magnetic fields, and can be used as a measure of magnetic induction, primarily for alternating magnetic fields.

A device for creating a weak uniform field is known which contains a power source, a current measuring means and a single-layer solenoid.

The minimum value of the generated magnetic induction is determined by the minimum value of the measured current and the conversion factor K a (connecting the value of the magnetic induction T TLZ with the value of the supply current I A, KB V / 1), which for given dimensions of the solenoid depends on the number of turns per unit length one.

However, this device does not allow you to get a floor of less than Tl, as this is associated with difficulties with precision-. measurement and stabilization of small-to-i

COB caused by the influence of noise and noise during the creation of variable magnetic fields.

It is also known a device for creating weak uniform magnetic fields, which contains a power source, current measuring means and two coaxial windings with a common center of symmetry and the opposite direction of their magnetic fields 2.

ten

However, the uniformity of the magnetic field in the working volume is insufficient.

The purpose of the invention is to increase the uniformity of the magnetic field in the working volume.

15

Claims (2)

This goal is achieved by the fact that a device for creating a weak uniform magnetic field containing two coaxial opposite-switched windings with a common center of symmetry, two resistors, one of which is connected in series with the first winding and the other in series with the second. each other, and the registering device, the first and second windings are made of a vein and a braid of a coaxial cable with the same diameter of turns, the number of turns and the step of winding. FIG. 1 shows a block diagram of the device; in fig. 2 is one of the constructive embodiments of a coil of two identical windings (in section). The device for creating a weak uniform magnetic field (Fig. 1) contains two coaxial windings Gui 2 with a common center of symmetry and the opposite direction of their magnetic fields, a power source 3, a recording device k, two resistors 5 and 6, one of which (5) is connected in series with the first winding 1 and the other (6) in series with the second 2, with both the circuits thus formed connected in parallel to each other, and both the windings 1 and 2 have the same diameter, number of turns and winding pitch. On the dielectric frame 7 (Fig. 2, a coaxial cable is wound with a coil, the cable core is winding 1, and the braid of this cable is winding 2. These windings are coaxial) and have a common center of symmetry, the same number of turns, winding pitch, average the diameter of the turn, i.e., the plane of the first turn of the first winding coincides with the plane of the first turn of the second winding and, accordingly, the planes of the subsequent turns. The device works as follows. When the power source 3 is turned on in the device winding circuits, mutually opposing currents are set, somewhat different in magnitude due to the inequality of the actual resistance values of these circuits. As a consequence, two completely identical magnetic fields are created in their spatial configuration, the magnetic induction vectors of which at each point in space are directed toward each other, but not equal in absolute value. Thus, an effective magnetic field is the difference between two opposing mafy-netic fields, and the recorded current of the device is equal to the sum of the currents of windings 1 and 2. The device conversion ratio is the ratio of the effective magnetic field to the recorded current of power, and compared with a single winding, it decreases in RfR2 / izl where R and R are the resistances of the circuits of the first and second windings (R R2). The ratio of the resistances of the circuits 1 and 2 is determined by selecting resistors 5, 6 in these circuits. By reducing the Kg conversion factor of the device by a factor of 250-300 compared with a single winding, the accuracy, uniformity and stability of the magnetic fields created by the device remain the same as the original single winding. The dependence of the magnetic induction on the frequency of the power supply current is not observed, since the device has a low inductance, and, therefore, there is no need. introduction of frequency corrections. The proposed device makes it possible to obtain rather weak magnetic fields with the same accuracy, uniformity, stability, and frequency dependence, as in the case of creating stronger fields, using standard power sources and current measurement tools without significant material costs. The invention The device for creating a weak uniform magnetic field containing two opposite coaxial windings with a common center of symmetry, two resistors, one of which is connected in series with the first winding and the other in series with the second, etc.) to a friend, and a recording device, characterized in that, in order to increase the uniformity of the magnetic field in the working volume, the first and second windings are made by dwelling and braiding of a coaxial cable with the same diameter ohm turns, the number of turns and step winding. Sources of information taken into account during the examination 1. Measuring equipment, 1968, 11, p. 77-78. and 2.Jungerraan J.D., Patten S.G. Rev. Scient Justrum, 31, I960, N- 2, p. 171., S -CZb f CZ    V a 4g. / / 2 FIG. 2