How to Interface an AC Buzzer with a DC Circuit

[BenSam]

this is my first time to use buzzer. i have no idea how.

I am planning to use an AC buzzer with a power supply 5Vp-p. datasheet **broken link removed** View attachment RS_BUZZER_120C_5V.pdf
how to drive it using My MC dispic33? is there any IC driver to include or i must use DC buzzer?

The reason why i use the AC buzzer, is the max temp. i could not find DC buzzer with a 120C.

 

[betwixt]

It isn't an AC buzzer, it's a piezoelectric transducer (loudspeaker). DC buzzers have a built-in oscillator so just sending 5V to them will make a sound. This one doesn't have the oscillator so you have to produce the sound waveform from your dsPIC instead.

All you have to do is write software to produce a signal, ideally a square wave, at about 4KHz. This could be a software loop toggling a pin but that would tie up much of the processor time, a better way would be to use a PWM output. I would advise you add a resistor in series with the dsPIC pin before connecting it to the buzzer, maybe 100 Ohms. The reason is that although the buzzer current is specified at 5mA which seems safe for the PIC, it has a very high capacitance which might overload the pin driver circuits, the resistor will isolate it enough to protect the PIC.

Brian.

 

[BenSam]

It isn't an AC buzzer, it's a piezoelectric transducer (loudspeaker). DC buzzers have a built-in oscillator so just sending 5V to them will make a sound. This one doesn't have the oscillator so you have to produce the sound waveform from your dsPIC instead.

All you have to do is write software to produce a signal, ideally a square wave, at about 4KHz. This could be a software loop toggling a pin but that would tie up much of the processor time, a better way would be to use a PWM output. I would advise you add a resistor in series with the dsPIC pin before connecting it to the buzzer, maybe 100 Ohms. The reason is that although the buzzer current is specified at 5mA which seems safe for the PIC, it has a very high capacitance which might overload the pin driver circuits, the resistor will isolate it enough to protect the PIC.

Brian.

Thank you Brian for the useful info.
Actually im required not to generate the signal from the MC. So, can i use another Ic driver such as 555 to produce the square wave?
is there any example circuit, pls refer it to me?

 

[betwixt]

You can use almost any oscillator to drive it, including the 555. For most volume from a 5V supply, produce two square waves from the same source where one is inverted from the other. Connect the transducer across the two outputs so instead of one side being 0V and 5V signal on the other, you alternate the 5V from one side to the other and effectively get 10V of drive. You could do this very easily using a hex inverter (74LS04, CD4069 etc.) where two inverters are used to generate the signal and two used to drive the transducer. You can use the dsPIC to enable or disable the oscillator to turn the buzzer on or off.

Brian.

 

[BenSam]

You can use almost any oscillator to drive it, including the 555. For most volume from a 5V supply, produce two square waves from the same source where one is inverted from the other. Connect the transducer across the two outputs so instead of one side being 0V and 5V signal on the other, you alternate the 5V from one side to the other and effectively get 10V of drive. You could do this very easily using a hex inverter (74LS04, CD4069 etc.) where two inverters are used to generate the signal and two used to drive the transducer. You can use the dsPIC to enable or disable the oscillator to turn the buzzer on or off.

Brian.

Thanks Brian.
Now i have a clear idea how to drive it.

Thanks and best regards