Power Generation
Before the previously mentioned circuits were used to accumulate the generated energy,
the amount of power this particular device could produce was measured. The results are specific
to this particular piezoelectric device because there are many factors that affect the power
generated, such as the substrate thickness, material used, excitation strength, and load resistance
used. In general, the maximum power output occurs when the impedance of the piezoelectric
element and the load resistance are matched. However, this cannot always be achieved during
testing because the piezoelectric is a capacitive device, which means that the impedance varies
with frequency, and therefore, the optimal load resistance varies. For the following power
generation results, the load resistance was set to be the impedance of the PZT at the resonant
frequency of the cantilever plate.
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The power generated by the PZT was obtained using the voltage drop across a 10kΩ
resistor. The power is calculated using the following relation obtained using Ohm’s law: