SU1465825A1 - Method of determining parameters of piezoelectric element - Google Patents

Abstract

The invention relates to the field of electrical measurements and can be used to measure the parameters of piezoelectric elements, including in the process of their manufacture. The aim of the invention is to expand the functional capabilities of the method by determining the frequency of antiresonance, as well as by ensuring that the parameters of the piezo elements are monitored during their manufacture. The method consists in supplying an alternating voltage with a varying frequency to the piezoelectric cell under test, registering a current flowing through the piezoelectric element, measuring frequencies f and fj corresponding to the maximum and minimum current, while the voltage to the piezoelectric element is fed where C "Co 1 through C - Q К static capacitance of piezoelemite; K- is an electromechanical coupling coefficient; Q - the quality factor of the piezoelectric element. Applying voltage to the piezoelectric element through a small capacitance, for example, through the air gap between the surface of the piezoelectric element and the coupling electrode, allows you to f 1 fi row with a quality factor Q 2 (f7 + f t to determine the frequency of the antiresonance sf f fy , 3 Fig. 0 1 (L with

Description

one

The invention relates to electrical measuring methods and can be used for. measurement of parameters of piezoelements., including in the process of their manufacture.

The purpose of the invention is to expand the functional capabilities of the method by ensuring control of the parameters of the piezoelements during their manufacture.

Figure 1 shows a diagram of a piezoelectric element (C is the static capacity of the piezoelectric element; C, L and R are its dynamic parameters); figure 2 - the dependence of the modulus of conductivity and the current flowing through the piezoelectric element of the frequency; on fig.Z - diagram of the device that implements the proposed method.

The essence of the method is as follows.

The piezoelectric cell under investigation (Fig. 1) is connected to the alternating voltage source through capacitor C,. Conductivity of series-connected piezoelectric element and capacitance C is defined by -; is expressed

Si

Od ate

00

to eat

In this case, the conductivity modulus according to (1) can be written as

JA + CAY-Bf ... Y.

- | -GGu - cr

1 + y2

(3)

1, Method for determining parameters of a piezoelectric element, including the application of an alternating voltage to a piezoelectric element with a varying frequency, recording the current flowing through piezo 2

The dependence of the conductivity module and, accordingly, the current flowing through the piezoelectric element from the h-frequency (figure 2) has extremes at y-1, 40 flowing current, calculating the quality factor Q by the formula

element, measurement of frequencies f and f corresponding to the maximum and minimum

from where

f, + and

f. f- f „-

Of

Q

I, C / f - g

1 s: 2 (

where Q is the quality factor of the piezoelectric element at the frequency of antiresonance.

The device implementing the method is shown in FIG.

35

Claims (2)

Invention Formula 1, A method for determining the parameters of a piezoelectric element, including applying an alternating voltage to a piezoelectric element with a varying frequency, registering the current flowing through the piezoelectric current flowing through current, calculating the quality factor Q using the formula 2 flowing current, calculating the quality factor Q by the formula element, measurement of frequencies f and f corresponding to the maximum and minimum Q f, + and ) characterized in that, in order to extend the functionality, the alternating voltage to the piezoelectric element is supplied through a capacitance 50   qb 55 where C is the static capacitance of the piezo element; K is the electromechanical coupling coefficient, characterized by the material of the piezoelectric element, and the frequency of antiresonance f. calculate. according to the formula f. (f, + fe) / 2. 51465825 2. The method according to p. 1, about tl and h. ω is the dielectric gap between the surface and the fact that the alternating voltage of the piezoelectric element and the conductor - voltage is applied to the piezoelectric element through the junction electrode. / U /. I /four With phases. i fi sa fz cpus.2