JPH04364481A - Measuring arrangement of impression of high voltage - Google Patents

Abstract

PURPOSE:To obtain a measuring arrangement of impression of high voltage which makes it possible to eliminate changeover of handling for the time of impression of high voltage and the time of measurement, to prevent impairment of a body to be inspected and to measure a frequency characteristic with high precision. CONSTITUTION:A DC high-voltage power source 1, a first switch 4 connecting the high-voltage power source or the earth alternatively to a ceramic resonator being a body 8 to be inspected, a frequency generator 5 generating an AC signal of a prescribed frequency, and a second switch 7 connecting the frequency generator selectively to the body to be inspected, are provided. Moreover, an I/V converter 9 converting a current flowing through the body to be inspected into a voltage, resistors 11 and 12 for regulation of the gain of the I/V converter, switches 13 and 14 switching these resistors, and an AC voltmeter 15 detecting a voltage conversion value of the impedance of the body to be inspected from an output voltage of the I/V converter, are provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for applying a high voltage to a test object such as a ceramic resonator and measuring the frequency characteristics of impedance.

0002

[Prior Art] Conventionally, when controlling the degree of polarization of a test object such as a ceramic resonator, high voltage is applied to perform polarization treatment, and after discharge, the frequency characteristics of impedance are measured. It is determined whether the difference) is within a predetermined range. When performing such high voltage application and measurement, first handle the specimen, apply high voltage, discharge, and then handle the specimen again for measurement.
Measuring frequency characteristics.

0003

However, this method has the problem that the handling must be changed between when high voltage is applied and when it is measured, and the object to be examined is likely to be damaged during the switching. Particularly in the case of ceramic resonators, the ceramic substrate is extremely susceptible to breakage due to external forces, so it has been an important issue to reduce the number of handling changes.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a high-voltage application and measurement device that eliminates handling switching between high-voltage application and measurement, prevents damage to the test object, and is capable of measuring frequency characteristics with high accuracy. There is a particular thing.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a DC high-voltage power supply, a first switching device that selectively connects the high-voltage power supply or ground to a subject, and a variable frequency A frequency generator that generates an alternating current signal, a second switch that selectively connects the frequency generator to the test object, and an I/V converter that converts the current flowing through the test object into voltage,
It is possible to measure the frequency characteristics of the object from the output voltage of the I/V converter.

When the first switch is switched to the high voltage power supply side,
Current from the high-voltage power source flows through the first switch to the subject, and high voltage is applied. Next, when the first switch is switched to the ground side, the charge charged in the subject flows to the ground through the first switch and is discharged. Thereafter, when the second switch is switched to the frequency generator side, an AC signal of a predetermined frequency flows from the frequency generator to the subject, and the I/V converter converts the current flowing through the subject into voltage. By measuring this voltage, the impedance of the object can be determined in terms of voltage. In this way, high voltage application, discharge, and measurement can be performed without changing handling.

Since the switching devices are separated such that the first switching device is used for high voltage switching and the second switching device is used for measurement, it is possible to select a switching device according to each purpose. Therefore, a measuring device with excellent contact reliability even for minute signals can be obtained.

As a method of measuring frequency characteristics, for example, the output voltage of the I/V converter may be directly measured using an AC voltmeter, or the output voltage (AC signal) may be measured in RMS/DC.
After converting into a DC signal corresponding to an effective value using a converter, this DC signal may be digitized using an A/D converter and analyzed.

In the case of a ceramic resonator, the resonant impedance is small and the anti-resonant impedance is large, so in order to adjust the gain of the I/V converter, a gain adjusting resistor and a gain switcher to switch between these resistors are required. It is desirable to provide one. This allows the output voltage of the I/V converter to be adjusted to a substantially constant level, making measurement easier.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a high voltage application measuring device according to the present invention. In the figure, 1 is a DC high-voltage power supply, 2 is an application limiting resistor, 3 is a discharge limiting resistor, 4 is a first switch for switching application/discharge, and 5 is a synthesizer etc. that generates an AC signal of an arbitrary frequency. A frequency generator, 6 a measuring resistor, and 7 a second measuring switch.

Reference numeral 8 denotes a test object such as a ceramic resonator, and both main surfaces thereof are handled by contacts. Reference numeral 9 denotes an I/V converter such as an OP amplifier, the positive input of which is grounded, and the negative input connected to one end of the test object 8 . 10 is a protection circuit connected between the positive and negative inputs of the I/V converter 9, and when a current exceeding a predetermined value flows through the I/V converter 9, this current is passed to GND, and the I/V This protects the converter 9. 11 and 12 are feedback resistors for gain adjustment of the I/V converter 9, and 13 and 14 are feedback resistors 11 and 12.
This is a switch for switching. 15 is an AC voltmeter that measures the output voltage of the I/V converter 9.

[0012] Here, the operation of the above-mentioned high voltage application measuring device will be explained. First, when high voltage is applied, the first switch 4 is switched to the high voltage power supply side 4a, and the second switch 7 is turned off. As a result, high voltage is applied from the high voltage power supply 1 to the test object 8 via the resistor 2.
is applied to Next, when the first switch 4 is switched to the discharge side 4b and the second switch 7 is turned off, the charge on the subject 8 is discharged to the ground via the resistor 3. The subject 8 is polarized as described above.

Next, to measure the frequency characteristics of the subject 8, the first switch 4 is set to the discharge side 4b, and the second switch 7 is turned on. As a result, an AC signal flows from the frequency generator 5 to the test object 8 via the resistor 6, and the current is converted to a voltage several times to tens of thousands of times higher by the I/V converter 9.
It is measured with a voltmeter 15.

Now, the output voltage of the frequency generator 5 is Vi
, the impedance from the frequency generator 5 to the test object 8 is Z
s, the impedance of the subject 8 is Zx, the feedback resistance of the I/V converter 9 is Zf, and the input voltage of the AC voltmeter 15 is Vo. Here, if Zs <<Zx, then the voltage Vo inversely proportional to the impedance Zx of the object 8
can be obtained. Therefore, by measuring the voltage Vo, the impedance Zx of the subject 8 can be determined.

FIG. 2 is a frequency characteristic diagram of the object to be tested (ceramic resonator). As is clear from the figure, the resonant frequency f
The impedance is minimal at r, and the impedance is maximal at anti-resonant frequency fa, so when the frequency of frequency generator 5 corresponds to resonance frequency fr, AC voltmeter 1
When the input voltage Vo of No. 5 is maximum and corresponds to the anti-resonance frequency fa, the input voltage Vo becomes minimum, and fr and fa can be easily detected. Then, the frequency difference Δf(fa −f
By applying high voltage so that r) falls within a predetermined range, the degree of polarization can be controlled.

Note that since the anti-resonant impedance Za is larger than the resonant impedance Zr, when measuring the anti-resonant point, the switches 13 and 14 are connected to the feedback resistors 11 and 12, which have a larger resistance value than when measuring the resonant point. All you have to do is switch. Thereby, the input voltage of the AC voltmeter 15 can be amplified to a value suitable for measurement at both the resonance point and the anti-resonance point, and measurement becomes easy.

[0017]

[Effects of the Invention] As is clear from the above explanation, according to the present invention, by switching the first and second switching devices,
High voltage application, discharge, and measurement without changing handling
Various types of work can be performed and damage to the subject can be prevented. Furthermore, since the current flowing through the object is directly measured by the I/V converter, the circuit can be made smaller and measurement error factors such as stray capacitance can be reduced. Therefore, highly accurate measurement values can be obtained. Furthermore, since the switching device is separated for high voltage use and measurement use, the switching device has a feature of high contact reliability in the case of minute signals.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an example of a high voltage application measuring device according to the present invention.

FIG. 2 is a frequency characteristic diagram of a ceramic resonator, which is an example of a test object.

[Explanation of symbols]

Claims (1)

[Claims] [Claim 1] A first switching device that selectively connects a high-voltage DC power source and a high-voltage power source or ground to a subject;
Equipped with a frequency generator that generates a variable frequency alternating current signal, a second switch that selectively connects the frequency generator to the test object, and an I/V converter that converts the current flowing through the test object into voltage. , a high voltage application measurement device that can measure the frequency characteristics of a test object from the output voltage of an I/V converter.