SU437990A1 - Device for determining a dynamic loop of magnetization reversal of ferromagnetic materials - Google Patents

Description

I

The invention relates to the field of magnetic measuring technology and can be used to register the dynamic cycle of magnetization reversal of magnetic materials in both digital and analog form. The results obtained by the device can be used to calculate other parameters of magnetic materials characterizing the behavior of the latter in alternating magnetic fields.

Devices are known for imaging and recording the dynamic cycle of magnetization reversal of magnetic (Matrix, which can, but be divided according to the principle of operation on ferrometers with a recording on a galvanometric scanner, ferrographs with a cathode ray tube and strobosconic devices, and only the latter allows direct recording dynamic cycle of magnetization reversal.

However, ferrometers and ferrographs depict a dynamic cycle of magnetization reversal only on the screen of an oscilloscope, and one of these devices does not display the measurement results in digital form. In addition, the accuracy of ferrographs with a recording on a cathode ray tube is low, and the errors of the stroboscopic device due to repeated direct signal conversion are significant.

The purpose of the invention is to increase the measurement accuracy.

This is achieved by the fact that the proposed device is connected in series by a reversible counter, a code analog converter, a comparator and a selective pulse shaper connected to the corresponding key in each measurement channel, as well as a logic device connected between the output of the selective pulse shapers and the reference pulse shaper and second inputs of keys and reverse counters. The second input of the comparator in the channel of the measured induction is connected with the output of the integrator, and in the channel of the measurement of the magnetic field strength - with the magnetizing winding of the test sample.

FIG. 1 shows a block diagram of the device.

Sample 1 has a magnetizing winding 2, which is connected to an AC voltage source 3. Nanometer, proportional to the intensity of the magnetic field in the sample, is removed from resistor 4, and from measuring winding 5, the voltage is proportional to the first derivative of induction in the sample. At the output of the integrator 6, there is a voltage proportional to the induction itself. Voltages proportional to the magnetic field polarity and magnetic induction are fed to the inputs of the comparators 7, 8, the second inputs of which are connected to the outputs of code-converter 9, 10 converters controlled by reversible counters 11, 12 connected via switches 13, 14 to the generator 15 pulses. The output signals of the comparators are received through selective pulse shapers 16, 17 on the inputs of the logic device 18. A output of the reference signal shaper 19 is connected to the third input of the same logic device, at its input a voltage proportional to magnetic induction is given. The output signals of the logic device control. the distribution of clock pulses, the counting direction of the reversible counters, the selective formatiro-20 drive of the pulses and the driver of the reference signal. The digital printer 20 and the discretization unit 21, which controls the digital printer, are connected to the outputs of the reversible counters, and the analog-25 digital recorder 22 is connected to the outputs of the analog-to-analog converter.

When the end of the compensating vector / C is stationary on the path of the magnetization reversal vector n Y ((0 and H (t is the instantaneous value of voltage proportional to the intensity of the field H; {in (O is the instantaneous value of voltage proportional to the induction E of sample B.) each rotation of the reversal vector occurs simultaneous balancing on both components only at the moment of coincidence of these vectors (Fig. 2). If the instantaneous value of the component of the compensating vector U "(t) is slightly smaller than that shown in Fig. 2, the balancing this component comes before equilibrium in component / ds (OE is the advance of the moment of equilibration of one of the components of the magnetization reversal vector in relation to the moment of equilibration of the second component between the two reference impulses MOR, which are detected at the upstream branch of the cycle at point D, registrations of the falling cycle branch at point G (Fig. 2) are used in a logic device to generate a control pulse of a compensating vector. In this case, opens

Subject invention

A device for determining a dynamic loop of magnetization reversal of ferromagnetic materials, containing an alternating current source, a test sample with magnetizing and measuring windings, an integrator, a driver of the reference pulses, a pulse generator connected to two keys in the channel for measuring the induction and field strength, analog and digital

recording devices, characterized in that, in order to improve measurement accuracy, it is equipped with a series-connected reversible counter, a code-analog converter, a comparator and a selective pulse shaper connected to the corresponding key in each measurement channel, as well as a logic device connected between the selective outputs pulse shapers and

the driver of the reference pulses and the second inputs of keys and reversible meters, the second input of the comparator in the induction measurement channel is connected to the output of the integrator, and in the magnetic field strength measuring channel - with the magnetizing winding of the test sample. the key 14 and the key 13 is closed, thereby receiving an increment of component / k (0 up to the moment when the equilibration of the component already and B (t) is ahead of the moment of equilibrating the component UH (Ov points A and E marked on the dynamic cycle (Fig. 2), the signal is formed in logic device 18 for switching the counting direction of the reversible counter 12, and at points C and for reversing the counting 13. Signals of the counting direction of the reversible counters simultaneously determine which edge of the signals in the comparators output and which reference signal using To form control pulses in the logic unit. (The arrow in Fig. 2 with the designation H indicates that, starting from the moment A, the reversible counter in the voltage channel subtracts and uses the negative edge of the comparator output signal; other symbols are decoded in the same way). After switching on the device, the compensating vector is first changed only by the component U. g g