SOLVED Buzzer - AC or DC?

  • Hi,

    The firmware code seems to assume that the buzzer is a piezo sounder that needs to be driven with the frequency at which it should beep ("Resonant frequency of the piezo sounder is 4.5kHz.")
    However at least on PanelDue V3 I only see parts that seem to be DC buzzers with their own oscillator (with a little "+" mark on the housing).
    Did the type of buzzer change over time / versions?


  • administrators

    The buzzer on PanelDue is and always has been a piezo sounder that needs to be driven by AC. It can be driven at any audible frequency, but it is loudest when driven near its resonant frequency.

  • Thanks for the clarification!
    Indeed when having a closer look at an original PCB, the little mark is an "S", not a "+". I guess I got confused by looking at some pictures in a web search, which showed cloned PCBs.

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