SU970290A1 - Device for reversal magnetization of ferromagnetic materials - Google Patents

Description

The invention relates to magnetic measurements and is intended for the reversal of magnetization of ferromagnetic materials by a field of any shape when determining their dynamic magnetic characteristics. Known automatic magnetizer demagnetizing mustache. The property contains two differentiating chains connected to the channels for measuring the intensity and the induction of the sample under study, an amplifier, a voltage-frequency converter, a binary reversible counter, a code-analog converter, an output amplifier, and a register (three ger), seven-bit binary counter, second transducer, analogue code, matching amplifier, switching and control elements 1. This device has a low frequency of magnetization reversal of the sample, because of the presence of a voltage-frequency converter in its circuit. This is explained by the fact that in order to obtain good accuracy at the output of the converter, the code is analogous to a voltage-frequency converter via a binary reversible counter, the output frequency of the latter cannot be high, therefore the speed of the device cannot be high. It is also known an automatic magnetizing device containing a series-connected pulse generator, a differentiating chain, a clock generator, a counter, a decoder, integrators on the number of outputs of the decoder, an adder, a multiplier, and a magnetizing coil of the sample, the second multiplier input is connected via a harmonic signal generator with the output of the pulse generator, and the measuring winding through the integrator is connected to the vertical channel of the oscilloscope, the horizontal channel l which is associated with a magnetizing coil and a resistor in its chain. This device has a higher frequency of the magnetization reversal current than in the previously discussed device 21. However, in the device, the frequency frequency of the magnetization reversal current is limited. The purpose of the invention is to expand the frequency range.

The goal is achieved by the fact that a device containing a magnetizing winding connected to it, a counter and a decoder of a MotaHOCTH amplifier and a magnetizing winding connected to it, as well as a summing amplifier, and a block of variable resistors whose output is connected to the inputs of a summing amplifier , as well as a low-pass filter, the output of which is connected to the input of the power amplifier, the input to the output of the summing amplifier, and the inputs of the analog key switch box yucheny to the output of the decoder.

The drawing shows a block diagram of the device.

The device consists of a series-connected pulse generator 1, counter 2, decoder 3, block 4 of analog switches, block 5 variable resistors, cyclical amplifier b, low-pass filter 7, amplifier 8 of power and magnetizing winding 9 of the sample. A positive + Uon and negative-Uon reference voltages are applied to the block of analog switches.

The device works as follows.

Generated by generator 1, rectangular pulses of a given frequency gradually fill counter 2, the states of which are analyzed by decoder 3. At the outputs of the decoder alternately pulses appear that open the analog keys of block 4 connected via these outputs Through an open analog key and through a variable connected to it the resistor of the block 5 to the input of the summing amplifier 6 under the action of positive + Uon or negative -UUP of the reference voltages applied to the inputs of the analog switches of block 4 passes a current, values which depends on the resistance of the variable resistor ,, in which the current flows. The output voltage of the summing amplifier is 6 step and repeating in shape a periodically varying input TC, the amplitude of which is set by adjusting the values of variable resistors, and the direction is connected to the inputs of the analog switches to a positive + Uon or negative - Ugp reference voltage. Smoothing the gradation of the output, periodically changing according to a given law, the voltage of the summing amplifier, is performed by a low-pass filter 7, after which the voltage is applied to the input of the amplifier 8

power for magnetizing winding 9 of a sample of current of the required form in a magnetized winding.

The generation of the forms of a magnetization reversal by high-speed devices (analog switches, variable resistors) allows significant. raise the upper limit of the frequency range of the magnetization reversal current. Introduction of a lower filter

Frequency allows to obtain current forms with continuous derivatives. By introducing a block of variable resistors, simplification of the tuning of the forma of the magnetizing current, the values of which determine it, is achieved.

Claims (2)

Invention Formula A device for magnetization reversal of ferromagnetic materials, containing a series-connected pulse generator, a counter and a decoder, a power amplifier and a magnetizing winding connected to it, as well as summation amplifier, characterized in that, in order to expand the frequency range, it is equipped with series-connected analog key block and block variable resistors, the output of which is connected to the inputs of the summing amplifier, as well as a low-pass filter, the output of which is connected to the input amplify power and input - with the output sum5 1daruyuschego amplifier inputs and analog switches connected to outputs of the block decoder. Sources of information taken into account in the examination 0 USSR author's certificate 387307, cl. G 01 R 33/14, 1973. 2. USSR author's certificate in application 2933745 / 18-21, cl. G 01 R 33/14, 1980.