7 years, 11 months ago.

What are the eletrical constraints connecting a buzzer to a PWM port?

Dear All,

I'd like to connect a piezo buzzer to a pwm port to create an audible alarm function with the RTC library of Erik Olieman. Alas, I couldn't find any hints about connecting a buzzer to a PWM port, e.g. max. allowed current, necessity of a resistor in series with the buzzer (like e.g. necesary for LEDs), etc.

Any hint and/or link will be very much appreciated.

Thank you very much in advance.

Best regards


1 Answer

7 years, 11 months ago.

It depends on which piezo buzzer you are using. Some should be fine directly connected, others will require a driver in between. For example this one: http://www.hobbytronics.co.uk/piezo-transducer-5v can be directly driven from an mbed. Others will require more power.

Also watch out that many piezo buzzers have a built-in oscillator, you turn them on by giving them a power supply, and then they make a fixed tone.

Accepted Answer