SU1674028A1 - Device for measurements of magnetic field strength - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the strength of magnetic fields. The purpose of the invention is to improve the measurement accuracy. The magnetic field strength meter contains a sawtooth generator and a measuring transducer consisting of a reed switch and a control winding. A new device is a controlled current source, the input of which is connected to the first output of the sawtooth generator, and the output is connected to the control winding of the measuring converter, the pulse generator, the control circuit whose first input is connected to the output of the measuring converter, and the second input c the second output of the sawtooth generator, a reversible counter, the first and second inputs of which are connected to the first and second outputs of the control circuit, the third input to the third output of the sawtooth generator April voltage, the fourth input - with the output of the pulse generator. 2 Il.

Description

The invention relates to a measurement technique and can be used to measure the strength of magnetic fields.

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

Fig. 1 is a block diagram of a magnetic field strength meter; figure 2 - the timing diagram of his work.

The magnetic field strength meter (Fig. 1) contains a sawtooth voltage generator 1, a measuring transducer 2 consisting of a reed switch. A 3 and a control winding 4. In addition, the device contains a controlled current source 5, the input of which is connected to the first output of the sawtooth generator 1, and the output to the control winding 4 of the measuring converter 2, the generator b of pulses, control unit 7, the first input of which is connected to the output of the measuring converter 2, and the second input is with the second output of the sawtooth 1 generator, a reversible counter 8, the first and second inputs of which are connected to the first and second outputs of the control unit 7, the third input to the third output of the generator 1 and the sawtooth voltage, a fourth input - with the output pulses of the generator 6.

The device works as follows.

After pressing the Start button in the generator 1 of the sawtooth voltage at its second output, a short pulse is output (see Ui 2 of FIG. 2), which drives the control unit 7 ONON

ABOUT

Yu

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nor in working condition. In addition, a short pulse is produced at the third generator output 1 of the saw-tooth voltage, which arrives at the third input of the reversing counter 8, resetting it to zero. At the same time point, the control winding 4 (Fig. 1) of the measuring transducer 2 receives an electric sawtooth signal from the output of the controlled current source 5 proportional to the controlled signal received from the first output of the sawtooth 1 generator 1 to the input of the controlled current source 5 that generates an alternating magnetic field along the axis of the reed switch 3. With a strength of H (0 (Fig. 2). At H (t) H2, the reed switch opens at time points ti, ta, and the signal Uz is sent to control unit 7. In turn from the first exit blo and control 7 is sent to the first input of the reversible counter 8 control signal Tracking - Subtraction - Ue.2 and to the second reversible counter 8 from the second output of the control unit 7 the signal to enable the counting Ue.1. U diagram illustrates the operation intervals of the reversible counter 8 Addition modes (sign +) and subtraction (sign -). The pulse generator 6 continuously produces rectangular pulses of frequency f0 and feeds them to the fourth input of the reversing counter 8. As a result, the output of the reversing counter 8 shows a digital code corresponding to th difference pulse numbers come ia a second input of the time intervals () and (ta-t / i), since in the absence of the measured external field they are equal, then at the end of the measuring cycle output down counter 8 ustanovits zero code. If there is an external measurable sex Hx, the equality of the periods (ti-ta) and (ta-t4) is violated, and when

Hx Hz is in the range of the closed state of the reed switch 3 (ts-te), during which the pulses with frequency f0 are added to the difference obtained. As a result, the output

the reversible counter 8 at the end of the measurement cycle will establish a code corresponding to the polarity and the value of Hx. At the end of a measurement cycle equal to one period of the sawtooth voltage produced

the sawtooth voltage generator 1, from its second output to the second input of the control unit 7, a short pulse arrives (see U 1.2), the outputting control unit 7 from the operating state characterizing

the presence of zero levels on all outputs of the control unit 7, thereby prohibiting the operation of the reversible counter 8.

Claims (1)

Invention Formula A device for measuring the strength of a magnetic field containing a sawtooth generator and a measuring transducer consisting of a reed switch and control winding characterized in that, in order to increase the measurement accuracy, a control unit, a reversible counter, a pulse generator, a controlled current source, whose input connected to the first output of the sawtooth generator, and the output to the control winding of the measuring converter; the first input of the control unit is connected to the output of the measuring the converter, the second input - with the second output of the sawtooth generator, the first and second outputs - with the first and second inputs, the third input of the reversible counter is connected to the third output the sawtooth generator, and the fourth input to the output of the pulse generator.