# Piezo buzzer current consumption

In my DIY project I need to decide do I want to use piezo buzzer (for sonar-like device) or not. To decide this I need to calculate current consumption of this device. Parameters I was able to find in datasheets for many different piezo buzzer discs include resonant resistance, resonant frequency and static capacitance, max voltage and SPL for some sample volt/freq (e.g. R=150 ohm, f=3.6 kHz, C=90 nF, SPL at 3.6 kHz = 91 dB). If I understand it right piezo buzzer should consume current same as resistor with resonant resistance if run at resonant frequency. I want to estimate what current it will consume on different frequencies and what SPL it will produce. Is there a way to estimate it theoretically using above information from datasheet? Will it be easier to just buy few discs and estimate it experimentally?

Update: I found that some piezo modules have SPL/freq diagram included in it's datasheet, so it is possible to estimate SPL in dB using this diagram.

• First determine if you are working with an actual piezo element or a module. The basic element is just the capacitive piezo piece, and with a DC input it doesn't make a sound and draws no current, you drive it with an AC voltage. A piezo module will have an oscillator circuit inside to drive the element, and is operated with a DC input, the input current will be less related to the output frequency. – Nedd Jan 15 '15 at 13:49
• I'm talking about piezo element, not module. And I'm planning to drive it by PWM. – gordon-quad Jan 15 '15 at 18:24