ultrasound - Piezo transducer current consumption

is there any way how theoretically determine the current consumption of ultrasound piezo transducer?

I only know impedance for res freq = 50 ohms and excitation voltage around -170 V.

Does the Ohms law work in this case?

Thank you.

Answer

It depends on what kind of signal you are driving it with. Ultrasonic transducers are pulsed, how much you pulse it is up to the designer, which you are going to want to keep minimize, 1) Not to waste power and 2) Not to dissipate large amounts of power into the thing you are measuring. A piezoelectric transducer is capacative and cannot be driven with a DC waveform (and you wouldn't want to, because you wouldn't have any signal to observe from waves reflecting off materials)

$$P_{avg} = \frac{1}{T} \int_0^{t}p(t) \,dt$$

If you have strictly a sine wave then A would be the amplitude:

$$ V(t) = A*sin(2\pi f t)$$

$$P_{avg} = \frac{1}{T} \int_0^{t}\frac{V(t)^2}{R} \,dt = \frac{1}{T} \int_0^{t}\frac{A*sin(2\pi f t)^2}{R} \,dt$$

or what ever function of voltage you are producing.