SU924628A1 - Method of measuring piezoceramic material mechanical quality - Google Patents

Description

The invention relates to radiophysical measurements and can be used to measure the electrophysical parameters, in particular the mechanical quality factor (ohms), of piezoceramic materials. A known method for measuring the electrical parameters of piezoresonators, according to which the parameters are determined at the moment when the reactive conductivity component of the resonator is zero, and the frequency value at this moment corresponds to the resonance tn. The disadvantage of this method is the limited measurement range of the parameters of the piezoceramic resonator and low measurement accuracy. The closest to the proposed method is the method of measuring the quality factor, according to which an electric signal is applied to the piezoceramic element under test which changes in the vicinity of the frequency resonant for the piezoceramic element, the frequencies fpH fg are measured at which the current through the piezoceramic element , the quality factor is calculated by the formula p i «2jR7e: .cf; Tf§-f | y where Rpgjj is the resistance of the piezoresonator at the resonant frequency f p; CQ is the capacitance of the piezoresonator at the resonant frequency 2}. The disadvantage of the known method is the need to measure four quantities, by which the quality factor is calculated, as well as low measurement accuracy. The purpose of the invention is to reduce the measurement time and increase the measurement accuracy. The goal is achieved by the method of measuring the mechanical quality factor of piezoceramic materials, which consists in applying an electrical signal to a piezoceramic element made of the piezoceramic material being investigated, and measuring the frequency of the signal, which is the response of the piezoceramic element to the input signal, from an electric signal, that is, the response of the piezoceramic element to the applied signal, allocate its imaginary component, change the frequency of the supplied signal to the field Cheney extreme values of the imaginary component and the frequencies corresponding to the extreme value of m yuschey- imaginary components of the signal, determining quality factor.

The drawing shows the functional electrical circuit of the device explaining the measurement method.

The device contains a generator 1 signal., A piezoceramic element 2, a resistor (R) 3, a phase shifter, a frequency meter 5, a synchronous detector 6, a voltmeter 7.

The device works as follows.

A sinusoidal electrical signal is supplied from the output of the signal generator 1 to the piezoceramic element 2. The signal from the resistor 3 is fed to one input of the synchronous detector 6. At the same time, the signal from the signal generator 1 is fed through the phase shifter k to another input of the synchronous detector 6. The output voltage of the synchronous detector 6 is recorded by a voltmeter 7. Using a phase shifter 4, a synchronous detector 6 is set in such a mode that, at its output, a signal is detected by a voltmeter 7, the amplitude of which is portion- nalna real or imaginary

the current component through the piezoceramics element 2. The frequencies f and fо are determined, corresponding to the extremums of the imaginary current component or half the level of the actual current component through the piezoceramic element 2.

The mechanical quality factor Q is determined by the formula

.Y

f,

, -f,

Where

Claims (2)

1. USSR Author's Certificate No. 388235, cl. G 01 R 29/22, 1971. 2. Glozman I.A. Piezoceramics. M., 1967, with ..