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Topic: May I use this tiny loudspeaker as a buzzer ? (Read 1 time) previous topic - next topic

amundsen

Hello,

I have a tiny loudspeaker taken from an LCD monitor.

Backside I read : 8 ohms - 1,5 W.

May I use it as a buzzer, or any other way ? Should I amplify or insert a resistor somewhere ?


Udo Klein

A capacitor would be more appropriate. Unlike a resistor it would not dissipate unnecessary amounts of power.
Check out my experiments http://blog.blinkenlight.net

amundsen

A capacitor ? What would it do ? Which value should I use ?

Udo Klein

It would protect against direct current because it effectively blocks it. It also would increase the amplitude of the signals reaching the speaker. The value depends on the frequencies and on the power that you want to transmit. Unless you specify exactly what you need/want it is impossible to tell you a value.

Google will find a lot of material covering the issue. This http://www.isce.org.uk/EnotesPDF/ENote%2022.2.pdf is some pretty good starting point.
Check out my experiments http://blog.blinkenlight.net

Udo Klein

One more thought: the maximum current rating for any Arduino pin is about 40 or 50mA. And you should leave some safety margin --> you can not drive much more than 5V*40mA --> 200mW --> Arduino can not overload this speaker without an amplifier. However the speaker can overload the Arduino. A suitable cap will protect against this as well.
Check out my experiments http://blog.blinkenlight.net

amundsen

Thanks Udo. However I don't understand the meaning of "overload" in your last message. Do you mean the speaker will draw too much power and put the card at risk ? How can a capacitor help (I suppose it's not used as a filter this time) ?

Udo Klein

If the speakers draws to much current this can destroy the controller or parts of it. The capacitor will act as a high pass. Since the speaker is approximately a low pass putting them into series will limit the current. Unless you hit the resonance frequency of course.

However this setup is much superior to a resistor because of the little power the Arduino can supply. The cap will create much less losses than a resistor.
Check out my experiments http://blog.blinkenlight.net

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