SU460520A1 - Device for measuring amplitude permeability - Google Patents

Description

one

The invention relates to a magnetically measuring technique and can also be used for electrical measurements.

A device for measuring the amplitude magnetic permeability of materials is known, consisting of an electromechanical unit including a magnetizing autotransformer, a peak detector, a switch instrument and a potentiometer.

The known device does not provide high accuracy of measurements due to the finite value of the resistance of the coil of the switch instrument, as well as speed.

The aim of the invention is to improve the accuracy and acceleration of the measurement process of the amplitude magnetic permeability, which is achieved by introducing a control circuit and a dividing unit connected between the amplitude fixing circuit and the display circuit and consisting of a series-connected key, low-frequency voltage-frequency converter and a selection circuit the period in the voltage channel and the high-frequency converter - the frequency in the induction channel, as well as the “And” circuit, the first input of which is ene yield assignment scheme period and an input control circuit, the second - the high-frequency transducer with output voltage - frequency and its outlet - inlet indication circuit. One output of the control circuit is connected to the second input of the display circuit, the second output is connected to the key input in the voltage channel, and the third output is connected to the 5th input of the period selection circuit.

The drawing shows a diagram of the proposed device.

The device consists of a source of magnetization 1, a circuit for recording amplitude values of voltages consisting of integrator 2 and peak detectors 3 and 4, a division unit containing key 5, voltage-frequency converters 6 and 7, period selection circuit 8, and 9, as well as an indication circuit consisting of a pulse counter 10 and a digital indicator 11, and a control circuit comprising a period counter 12, differentiating chain buttons 13 of elements 14 and 15, and also of switch 16 for two directions.

The source of magnetization I, depending on the measurement mode, is either a high output impedance circuit (source of sinusoidally varying voltage) or a low output impedance circuit (source of sinusoidally varying induction). The integrator 2 is configured as an AC amplifier with negative feedback. Peak detectors 3 and 4 are transducers

variable voltages in constant, proportional to the amplitudes of the voltages on the primary and secondary windings of the core under study. Key 5 is the " two inputs " circuit. Voltage-to-frequency transducers 6 and 7 are controlled oscillators of relaxation oscillations - multivibrators. They are constructed according to the same scheme using the same semiconductor elements and differ only in the parameters of the time of the driving arms. Period allocation circuit 8 is a trigger with a counting input.

The device works as follows.

The voltage proportional to the intensity I of the magnetic field in the core enters the peak detector 3 of the channel I, and then through the key 5 to the converter 7, so that the input voltage is converted into a series of square pulses, the frequency of which is normalized by the Yamax intensity and the period of their repetition is inversely proportional to the value of the Yamax B core. The voltage proportional to the dB value is fed to the integradt

torus 2, and then through peak detector 4 of channel B to converter 6, therefore the frequency of the pulses at the output of the converter is proportional to the magnitude of You and x in the core. Circuit 8 generates pulses with a duty cycle equal to two from the low-frequency signal in the voltage channel, which are fed to one input of an AND 9 circuit, to the other input of which pulses are received with a high repetition rate from the induction channel, so that burst. The number of pulses in each packet is proportional to the amplitude magnetic permeability, since the repetition frequency is low

HF signal frequency - proportional

Yamax value, and the frequency of repetition of the high-frequency signal is proportional to jSjiaKc and, therefore,

 max g TG - ,, - HF

The number of pulses In several consecutive bursts is recorded by a pulse counter 10 and a digital indicator 11, and the number of periods of the low-frequency signal is recorded by a counter of periods 12, the output pulse of which opens key 5, stopping the measurement process. The output pulse of the period counter 12 through the switch 16 also acts on the second input of the digital indicator I, fixing the position of a comma in the displayed number. When the button 13 is closed, circuit 8

a period selection, a pulse counter 10, a digital indicator 11 and a period counter 12 are reset.

Subject invention

An amplitude magnetic permeability measurement device comprising a magnetisation source, an amplitude value fixing scheme consisting of a peak detector in a voltage channel and an integrator and a peak detector in an induction channel, and an indication circuit characterized in that, in order to improve accuracy and speed up the process measurement, it is equipped with a control circuit and a dividing unit connected between the amplitude value fixing circuit and the display circuit and consisting of a series-connected key, low-frequency reobrazovatel-frequency voltage and isolation circuit period in a channel

voltage and high-frequency voltage-frequency converter in the induction channel, as well as the AND circuit, the first input of which is connected to the output of the period-selection circuit and the input of the control circuit, the second

with the output of the high-frequency voltage-frequency converter, and its output - with the input of the display circuit, with one output of the control circuit connected to the second input of the display circuit, the second output - with the key input in the voltage channel, and the third output with the input of the period selection circuit . : g I I L.