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I'm guessing it might be mechanically excited. How would you model that? I would think the response to loading would depend on the mechanical "impedance" of the mechanical exciter.
The problem with modelling piezo's is that their capacitance and inductance change with frequency. You can keep a piezo capacitive or inductive by choosing the frequency. Modelling for changes to capacitance and inductance is mighty difficult. If anyone has an idea how to do it i'd be interested in knowing.
Do you have the curves for the piezo? If you have curves for L and C you could use them to come up with a model. If F is the only independent variable, then L and C would depend on that alone. Sounds like numerical analysis though. I've done nonlinear inductors before where L partly depends on DC current flow.
Arent there any models out there somewhere on the web or something?
If your source has zero impedance then the voltage applied to your bridge of rectifiers will be unchanged by the current drawn by the piezo resonator. If your source has some non-zero impedance, then the current drawn by the piezo resonator will cause a voltage drop in the source impedance, and less voltage will be available for the recitifier bridge.
The way to model the source impedance in spice is to simply put a resistor (possibly with some reactance as well) in series with the source.
What is the nature of your physical source? Is it a signal generator, or some kind of amplifier? Do you know what its internal impedance is?
To find out its internal resistance, set up your source to provide an output without a load and connect a voltmeter or oscilloscope to the output to measure it. Apply a resistive load, perhaps a variable resistor, and vary the resistance until the output of the source drops to 1/2 of the unloaded value. Then the value of the resistive load is equal to the internal resistance of your source.
I'm guessing it might be mechanically excited. How would you model that? I would think the response to loading would depend on the mechanical "impedance" of the mechanical exciter.
The problem with modelling piezo's is that their capacitance and inductance change with frequency. You can keep a piezo capacitive or inductive by choosing the frequency. Modelling for changes to capacitance and inductance is mighty difficult. If anyone has an idea how to do it i'd be interested in knowing.
Do you have the curves for the piezo? If you have curves for L and C you could use them to come up with a model. If F is the only independent variable, then L and C would depend on that alone. Sounds like numerical analysis though. I've done nonlinear inductors before where L partly depends on DC current flow.
Arent there any models out there somewhere on the web or something?
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