Piezo buzzer - no polarity marks

It expects to be driven by an alternating voltage. If you connect it to a DC source, a battery for example, it will just go *tick!*.

Jeroen Belleman

It is not a buzzer, it is a transducer.

A transducer is a device that can convert (in this case) sound to electricity or electricity to sound. To use that as a buzzer you will need to drive it with an oscillator, at 2.04 kilo hertz and a wave with a 5 volt peak to peak amplitude (to get the maximum noise out of it)

It doesn't have the polarity indicated because it has no polarity. Think of it as a loudspeaker (another transducer since they can be used as microphones and convert sound to electricity)

It will work at other frequencies with less volume. It should click when you put a battery on the leads, and click again when you reverse the polarity of the battery. (it also stores a charge like a capacitor)

Look up oscillators if you want to use it as a buzzer. The 555 makes a dandy oscillator.

Ok. I want to replace the current piezo buzzer I have with something that will fit on my breadboard.

It's a pulse type which I do not like.

Andy

I like bells myself. I cut a chime bar from some hard aluminum alloy and used a solenoid to pull down on a mallet to strike the bar. It sounded bad (with all the mechanical noise the solenoid made) and I ended up using a 555 as a monostable timer to get just the right timing on the stroke of the mallet.

I hate piezo buzzers. Even a speaker driven with a 555 sounds better to me.

What specs do I need to look for the speaker?

My circuit runs from 9 vdc.

Andy

Any small speaker should work. There's dozens of paper cone speakers in a 2-3" size that make good annunciators. If you have a junk radio you can cannibalize a speaker from it. I'd use 8 ohms or higher would be my choice if I was buying one. You would also need/want an electrolytic cap of 10-100 uf to use in series with it to keep DC off the speaker.

Thanks.