SU866503A1 - Piezoelectric module measuring device - Google Patents

Description

(54) DEVICE FOR MEASURING PIEZOELECTRIC

one

The invention relates to a technique for measuring the electrophysical parameters of nieseceramic materials and can be used to measure piezoelectric modules of piezocrystals.

A device for measuring a piezoelectric module, comprising a reference piezoelectric element, subjected to mechanical force compression by an electromagnet, voltage amplifiers taken from a reference and measurable piezoelectric elements, a reference element and a digital display unit D, is known.

Its disadvantage is the need to verify and maintain the stability of the characteristics of the reference piezoelectric element.

It is also known a device for measuring voltage in digital form (including voltage generated after mechanical action on a piezoelectric element), which contains three

MODULE

key, integrator, comparator, counting pulse generator, digital counter, trigger and display unit C23.

The disadvantage of it is the impossibility of determining the piezoelectric module in digital form.

The purpose of the invention is to automate measurements.

The goal is achieved by the fact that the device contains two entrances of the device, one of which is connected to the device body, and the second to the input of the first key; The control input is connected to the first output of the trigger, the second output connected to the control input of the second key, the output connected to the output of the first key and the integrator's input, the output of which is connected to one of the comparator inputs, the second input co-20 common to the device body, and. a counting pulse generator, an output connected to a control input of a third key, the output of which is connected via a digital counter to the display unit, a second trigger, an amplifier, a mechanical force sensor and a pulse generator of a predetermined duration, the input of which is connected to the Start input, and the first output of This generator is connected to one of the trigger inputs, a second input connected to the second output of a pulse generator of a given duration and one of the inputs of the second trigger, the second input of which is connected to the output at the comparator, and the output of the second trigger is connected to the input of the third key, while the mechanical force sensor is connected via an amplifier to the input of the second key. FIG. 1 shows a block diagram of the proposed device; 2, the time dependences of the signals at some nodes of the device block-cxe. The device contains an electromagnet for mechanical loading of the test piezoelectric element 2, a mechanical force sensor 3, an amplifier 4, keys 5 and 6, an integrator 7, a comparator 8 trigger 9, a pulse generator 10 of a predetermined duration, a trigger 11, a generator 12 counting pulses, a key 1 digital counter 14, the display unit 15, the inputs of the device 16 and 17, and the Start input 18. The device operates as follows. The measurement cycle starts with the fact that at time t (Fig. 2) a pulse generator 10 of a predetermined duration opens switch 6 through key 9 and closes key 5 and loads the test piezoelectric element with force F. During time T (Fig. 2) the charge from the piezoelectric element completely flows through the input resistance of the integrator. The voltage at the output of the integrator 7 increases according to the law tj (-CH 4 "), t where Q is the charge formed on the sample due to the direct piezoelectric effect; Cd is the proportion ratio. Under the influence of the applied load, the mechanical force sensor 3 generates an electrical signal, which, after it is amplified, by a snubber 4 enters the input of a private key 5, and the output voltage amplify 4 is the Lunein function of the force F of the load Up KpF, de Kr is a constant This is done when calibrating a mechanical force sensor. After a time interval T ,, when Apr J i (f) I, generator 10 closes key 6 and opens switch 5. Thus, at the time to the input of the integrator 7, the voltage U, opposite to the voltage sign, and ({ ) 1 ({) - У0.4, „t. In addition, at time t, the momentum from. Generator 10 through trigger II opens key 13 and pulses with frequency o come from generator 12 to the input of digital counter 14. At time tg, f when Qi comparator 8 rely on trigger 11 turns off key 13 and terminates the access of pulses to counter 14. Pulse arrival time t The counting of the counter 14 - is determined from the condition X bx e QbffMt i alUpcJt kg-QrkgkpJpai Considering that F is the steady-state value of the loading force, a constant value for a given measurement cycle, the last relation can be rewritten as M-Q. (or p- - Kptx Pr the definition of the piezoelectric module dj in It is expressed by the relation d33 Then, taking into account the previous expressions d33 Mir Thus, the number of pulses recorded by the display unit 15 during the time tj (determined from the ratio N - tx fo Then the time tj is determined from the formulaN t and t, and the piezoelectric module it is easy to determine from the relation. N 7o The number of pulses transmitted to the sampling device as a function of the piezoelectric pattern is determined from the expression

N

Cr the Formula of Invention

A device for measuring the piezoelectric module, which contains two inputs, one of which is connected to the device case, and the second to the input of the first key, the control input of which is connected to the first output of the trigger, the second output connected to the control input of the second key, the output connected with the output of the first key and the integrator input, the output of which is connected to one of the inputs of the comparator, the second input connected to the housing of the Device, and the counting pulse generator, the output connected to the control input of the third key, the output of which is connected to the unit through a digital counter

indications, characterized in that, in order to automate measurements, a second trigger, an amplifier, a mechanical sensor

force and a pulse generator of a given duration, the input of which is connected to the Start input, and the First output of the alternator is connected to one of the trigger inputs, - the second input connected to the second output of the pulse generator specified by the capacitor. one of the inputs of the second trigger, whose second input is connected to the output of the comparator, and the output of the second

trigger is connected to the input of the third key, while the mechanical force sensor through the amplifier is connected to the input of the second key.

Information sources,

taken into account in the examination

1. The patent of France 1 2197459, class, G 01 About 1/00,

2. Shl ndin V.M. Digital measuring transducers and devices 1973, p. 186 (prototype).

Claims (2)

Claim A device for measuring a piezoelectric module, containing two inputs, one of which is connected to the device case, and the second to the input of the first key, the control input of which is connected to the first output of the trigger, the second output connected to the control input of the second key, the output connected to the output of the first a key and an integrator input, the output of which is connected to one of the comparator inputs, a second input connected to the device case, and a counting pulse generator, an output connected to the control input of the third a beam, the output of which through a digital counter is connected to an indication unit, characterized in that, for the purpose of measuring automation, a second trigger, an amplifier, a mechanical 5 force sensor and a pulse generator of a given duration are introduced into it, the input of which is connected to the Start input, and the First output the mentioned generator is connected to one of the inputs of the trigger, the second input connected to the second output of the pulse generator of a given power and one of the inputs of the second trigger, the second input of which is connected to the output of the comparator, and you the second stroke of $ 1 trigger is connected to the input of the third key, while the mechanical force sensor through the amplifier is connected to the input of the second key. Sources of information, 2Q taken into account in the examination 1. French patent 2197459, CL G 01 0 1/00, 1974. 2. Shlyandin V.M. Digital Transducers and Instruments, 1973, p. 186 (prototype). ВНИИПИ Order 8072/68 Circulation 735 Subscription Branch of the PPP Patent, Uzhgorod, Project 4,