Measuring the output voltage of piezoelectric sensor

Thread Starter

AbanahJ

Joined Jan 27, 2022
3
I have developed a piezoelectric pressure sensor using nano-fabrication which reads 10-25 mV in multimeter. I want to capture time vs Voltage waveform when pressure is applied by touching the sensor. I tried measuring by connecting both the ends of sensor to the probe of oscilloscope but I am not able to get any pulse when pressure is applied. What may be the reason and how to measure time vs voltage graph for my pressure sensor. I would be much pleased if I get the answer I am searching for. Thanks in advance.
 

MrChips

Joined Oct 2, 2009
25,928
Typical piezoelectric transducers are very good at generating voltages.
A 1-inch diameter transducer easily puts out 2 to 5 volts when struck.
 

Alec_t

Joined Sep 17, 2013
12,744
I tried measuring by connecting both the ends of sensor to the probe of oscilloscope but I am not able to get any pulse when pressure is applied. What may be the reason and how to measure time vs voltage graph for my pressure sensor.
Piezo transducers have an extremely high impedance. It is likely that your 'scope input impedance is forming a voltage-divider with the piezo's impedance and pulling the voltage down. A buffer stage with an extremely high input impedance (e.g. using a MOSFET) between piezo and scope might work. Voltage clipping to protect any MOSFET gate would be advisable, since piezos can generate high voltages if struck hard.
 

Thread Starter

AbanahJ

Joined Jan 27, 2022
3
Piezo transducers have an extremely high impedance. It is likely that your 'scope input impedance is forming a voltage-divider with the piezo's impedance and pulling the voltage down. A buffer stage with an extremely high input impedance (e.g. using a MOSFET) between piezo and scope might work. Voltage clipping to protect any MOSFET gate would be advisable, since piezos can generate high voltages if struck hard.
My piezo sensor generates only 10-20 mV. How to measure the impedance of my piezo sensor that I have developed. So that I can develop my circuit according to it.
Thanks in advance!
 
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