SU69465A1 - Method of measuring tg (f) inductors - Google Patents

Description

In those areas of electrical engineering in which high-frequency oscillations are used, the evaluation of the inductors is often made according to their quality factor QX, equal to Qx

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For measuring the quality factor, complex instruments are used, usually for several measurement limits and with the possibility of a wide frequency variation.

For production purposes, instruments that are easy to handle and which allow a readout of the measured value of the quality factor at a certain frequency to be obtained are necessary.

The present invention provides a method for measuring the tg of inductance coils, which makes it possible to use for measurement a simplified instrument such as an unbalanced bridge circuit containing an inductor in one of the arms with the smallest permissible quality factor.

A high impedance indicator (such as a lamp voltmeter) is included in the pavement diagonal, and the pointer device included in its composition can have a scale directly calibrated in terms of quality values. According to the invention, a composite consisting of two reference resistances and one reference impedance, whose value is equal to the resistance of the underlying reference resistance, is applied, and the value of the tested self-induction coil is judged by the minimum value of the bridge measuring indicator deflection the magnitude of the second reference active resistance.

FIG. Figure 1 shows a schematic diagram of a bridge used according to the proposed method, and FIG. 2 and 3 - indicator scales with different reference rollers.

In the circuit of FIG. 1 and - active resistances, LQ and R - inductance and resistance of a known exemplary roller with a quality factor QO and with an impedance Zg, LX and RX - inductance and resistance of a measured object with a quality factor. Qx.

169Measurements must be made at a constant voltage at the entrance of the bridge; the measurement process is reduced to a change in resistance to a minimum reading on the scale of the indicator; this count is obtained at Zx.

The reading on the indicator scale over wide limits does not depend on the absolute value of the inductance of the measured coil.

It is recommended to use an indicator that easily withstands overloads.

At Q 10, the scale of the instrument has the character shown in FIG. 2, at Q 50, the scale of the instrument has the character shown in FIG. 3

Subject invention

A method of measuring ig (p inductors with the help of an unbalanced ac bridge, characterized in that a bridge consisting of two reference active resistances and one reference impedance, the value of which is equal to the resistance of the lying reference resistance, and ig ( p the tested self-induction coil is judged by the magnitude of the minimum deflection of the gauge indicator of the bridge that occurs when the value of the second reference active resistance changes .

FIG. I

ig. 2 20 50

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FIG. 3 SE

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200

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