Hello Sirs,
Few week ago, I’m using oscilloscope to find a piezo resonant, but could find it.
In my knowledge when resonant frequency will be maximum current and phase shift was zero. But until now I couldn’t found this frequency. If I’m using impedance analysis to find how to connect my device?
My device was a flex bond with piezo and top plate has SUS material to fix.
Input signal from flex driver line and through the piezo end of SUS material.

 

Hello there Assemble this circuit as shown

Set digital multimeter to AC voltage measurement.
Start function generator and set output to sine wave with an initial frequency below the expected resonance.
Set drive voltage to 5-10V.
Slowly increase frequency on the function generator. Monitor the voltage across the resistor. Voltage should increase as frequency increases.
Continue increasing frequency until the voltage begins to decrease again. There should be a very small frequency range (~1Hz) where the voltage is greatest. The center of this range is the resonance frequency.

 

Bit worry that probe`s capacitance is the same order of magnitude the crystall and may heavy shift the frequency off. Better to use the VNA as they are designet to operate with sub-pF DUT~s. Both economy class devices N1201SA and NanoVNA are well suited for such task.

SA is expensiver but far more easy to understand and operate.

Shall give a pictures how it all looks (if buy at first search a best price between sellers as I not take any time to look on the pricing)

SA1 for 137 MHz to 2,7 GHz, one port https://www.ebay.com/itm/N1201SA-UV...=362999881072ac99675233064576a4c3c4867327d523

SA1++ with altered low frequency range https://www.ebay.com/itm/N1201SA-35...470358&hash=item1ce1f91e53:g:GqoAAOSwzzVbJcQX

Nano - zero to 3 GHz, two ports https://www.ebay.com/itm/NanoVNA-V2...315965?hash=item421c29633d:g:F-UAAOSw4Q9fBGAp

Nano, up to 1 GHz with larger screen (what is very important) https://www.ebay.com/itm/4-3-inch-I...=3531709842271d204bc0a8aa4811bb04849ad200dc8b

Cheap Nano up to 900 MHz https://www.ebay.com/itm/Nuovo-50KH...=2741073355491d204bc0a8aa4811bb04849ad200dc8b

 

thanks your help！

Hello there Assemble this circuit as shown
View attachment 215171
Set digital multimeter to AC voltage measurement.
Start function generator and set output to sine wave with an initial frequency below the expected resonance.
Set drive voltage to 5-10V.
Slowly increase frequency on the function generator. Monitor the voltage across the resistor. Voltage should increase as frequency increases.
Continue increasing frequency until the voltage begins to decrease again. There should be a very small frequency range (~1Hz) where the voltage is greatest. The center of this range is the resonance frequency.