SU1307407A1 - Device for measuring parameters of barkhausen effect - Google Patents

Abstract

The invention relates to the field of magnetic measurements and can be used to study the properties of ferromagnetic materials and products, mainly of complex geometric shape. An introduction to the device for measuring the parameters of the Barkhausen effect of the high-frequency generator 7, the analog switch 8, the impedance meter 9, the analog storage unit 10, the nonlinear element 11, the detector 12 and the zero organ 13 increases the measurement accuracy by reducing 5 and the effect of the gap between induction transducer and ferromagnetic sample. 2 Il. S Faie.1

Description

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The invention relates to magnetic measurements and can be used to study the properties of ferromagnetic materials and products, especially of complex geometry,

The aim of the invention is to improve the measurement accuracy by reducing the influence of the gap between the induction transducer and the ferromagnetic transducer.

FIG. 1 shows a block diagram of the device; FIG. 2 shows timing diagrams explaining its principle of operation.

A device for measuring the parameters of the Barkhausen effect (FIG. 1) contains a series-connected alternating bias current 1, a power amplifier 2, an induction converter 3 for detecting Barkhausen noises, an amplifier 4 and a recording unit 5, an integrator 6, sequentially connecting high-frequency oscillator 7, analog switch 8, impedance meter 9, analog storage unit 10 and nonlinear element 11, as well as a serially connected detector 12 and zero organ 13, the integrator 6 is connected between winding 14 feedback the converter 3 and the second input of amplifier 2; the output of the analog switch 8 and the input of the impedance meter 9 are connected to the measuring winding 15 of the converter 3. The output of the nonlinear element 11 is connected to the control input of the amplifier 4, the output of which is connected to the input of the detector 12, The output of the zero-organ 13 is connected to the control input of the analog switch 8. The converter 3 also contains a magnetizing winding 16 and a magnetic circuit 17. The generator 1, the amplifier 2 and the integrator 6 with the winding 14 form a magnetizing bridge. Lok 18.

The operation of the device, taking into account the timing diagrams (Fig. 2).

The generator current 1, proportional to the signal and amplified by amplifier 2, and flowing through the winding 16 of the induction converter 3, creates a magnetic flux that closes along the magnetic conductor 17 of the converter 3 and the ferromagnetic sample 19 In order to maintain a given law of induction, the device has b realized with the help of additional winding 14 of converter 3 and integrator 6. In measurement 25

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Q. in the fuse winding 15, the emf of the Barkhausen noise (signal AND in Fig. 2) is induced, which is then amplified by amplifier 4,

The effect of the gap on the emf of Barkhausen noise (BF) is corrected as follows.

The current of the high-frequency generator 7, flowed across the winding 15 of the converter 3, creates an alternating field. The frequency of the generator 7 is chosen in the range of 800-1000 kHz. In this case, it can be considered that the insertion resistance of the winding 15 depends only on the gap between the transducer 3 and the ferromagnetic sample 19. The output signal of the impedance meter 9 is fixed by the block 10 and is fed to the input of the nonlinear element 11, the output of which controls the gain of the amplifier 4 and thereby compensating for the effect of the gap. The characteristic of the nonlinear element 1i allows linearizing the dependence of the emf of the SB on the gap and is constructed taking into account the nonlinear connection between the gap and the Bnosim1) 1m resistance of the winding 15 of the converter 3.

The independence of the magnetization reversal conditions from the high-frequency signal is caused in the device by the separation of the emf of the SB and the signal generator of the generator 7 in time. The detector 12 extracts the envelope of the EMF 1CB (signal U in Fig. 2), which is converted by the null organ 13 into a square signal (IJ4 in Fig. 2). The output signal of the zero-organ 13 controls the operation of the analog key 8. With a non-zero signal U, key 8 disconnects generator 7 from converter 3, and in the absence and passes the high-frequency signal of generator 7 to converter 3 (signal U in Fig. 2). Since the upper frequency bandwidth of amplifier 4 usually does not exceed 300 kHz, the high-frequency signal of generator 7 does not pass to the input of detector 12 and does not affect the operation of analog switch 8,

Thus, periodically connecting the oscillator 7 allows the adjustment of the amplifier 4. At the same time, the output voltage of the unit 10 remains constant for a half-period of the magnetization reversal. This makes it possible to almost completely eliminate the influence of gap instability on the result of measuring the EMF of SB.

Claims (1)

Invention Formula A device for measuring the parameters of the Barkhausen effect, containing a series-connected alternating magnetization current generator, a power amplifier, an induction transducer, an amplifier, and a recording unit, characterized in that, in order to increase the measurement accuracy, a series-connected high-frequency generator, analog switch, meter A full sonoctule, an analog storage unit and a non-linear element, as well as a sequentially connected detector and a null organ, the output of which is connected to the control input of an analog switch, is input connected to the impedance meter, and the detector input is connected to the input of the unit registration and to the output of the amplifier, the control input of which is connected to the output of the nonlinear element. Editor I, Gorvat Compiled by S. Shumilishska Tekhred L. Oleinik Order 1629 / 4fST Circulation 731 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Фа2.2 Proofreader M. Demchik Subscription