Electrical properties Piezoelectric sensor

schematic symbol , electronic model of piezoelectric sensor

a piezoelectric transducer has high dc output impedance , can modeled proportional voltage source , filter network. voltage v @ source directly proportional applied force, pressure, or strain. output signal related mechanical force if had passed through equivalent circuit.

frequency response of piezoelectric sensor; output voltage vs applied force

a detailed model includes effects of sensor s mechanical construction , other non-idealities. inductance lm due seismic mass , inertia of sensor itself. ce inversely proportional mechanical elasticity of sensor. c0 represents static capacitance of transducer, resulting inertial mass of infinite size. ri insulation leakage resistance of transducer element. if sensor connected load resistance, acts in parallel insulation resistance, both increasing high-pass cutoff frequency.

in flat region, sensor can modeled voltage source in series sensor s capacitance or charge source in parallel capacitance

for use sensor, flat region of frequency response plot typically used, between high-pass cutoff , resonant peak. load , leakage resistance must large enough low frequencies of interest not lost. simplified equivalent circuit model can used in region, in cs represents capacitance of sensor surface itself, determined standard formula capacitance of parallel plates. can modeled charge source in parallel source capacitance, charge directly proportional applied force, above.