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Topic: Piezo buzzers and piezo elements (Read 290 times) previous topic - next topic

Joprp05

This is... kind of a dumb question, but i'll ask anyway.

Does the piezo buzzer make the same things as a piezo element?

You know the difference between them two, right smart people out there?
Do they act the same as eachother?
If you tried various times and it didn't work, take a break, relax and come back later

Wawa

Not a dumb question.
Lots of websites give confusing/wrong information.

Piezo: passive piezoelectrical device that can be used as vibration sensor (microphone) or to make sound (speaker).

Buzzer: A 'thing' that makes a 'buzzing' sound (can be anything electrical or mechanical).

Some 'buzzers' are passive (you have to provide a tone), some are active (tone generator buildin).

One way to test if a buzzer is active or passive is to connect a DC voltage (5volt) to it.
If it makes a tone, it's active, and you can't use it as as a speaker (for custom tones/sound).

So "piezo buzzer" tells me that it's made of a piezo element and can make sound.
But it doesn't tell me if it's active or passive.
Leo..


 

DVDdoug

When in doubt, check the manufacturer's datasheet.   (Reliable suppliers will give you a manufacturer's part number or a link to the datasheet.)

A (active) buzzer will have a DC voltage rating and fixed-frequency.

A transducer will have a frequency range  and an AC voltage rating (or AC voltage sensitivity such as 90dB @ 1V RMS @ 2kHz.)    Most transducers are used as speakers but there are acoustic-guitar microphones and drum "triggers" made from piezo elements.    Some cheap "ceramic" phono pickups are piezo's.

An "element" wouldn't have any electronics and probably no case/housing.

Joprp05

Thank you for the answers, that helped me a lot.
Just one more thing : I know piezo elements can create electricity (by means of tapping them), so theoretically buzzers can also do that?

If you tried various times and it didn't work, take a break, relax and come back later

Wawa

I know piezo elements can create electricity (by means of tapping them), so theoretically buzzers can also do that?
If you tap a piezo element, or a loudspeaker type buzzer, then yes.
If you tap a mechanical 'claxon' type buzzer (common) then no.
Leo..

Joprp05

So, my buzzer is the wt-1205; and I connected it to the 5v in arduino and it didn't do anything.... soooo, is it a passive one?
If you tried various times and it didn't work, take a break, relax and come back later

Wawa

#6
Nov 14, 2017, 11:00 am Last Edit: Nov 14, 2017, 11:08 am by Wawa
Google "WT-1205 datasheet".
The WT-1205 seems to be an electromagnetic (not piezo) passive buzzer, with a resonance frequency of 2.4kHz.
~47ohm (100mA peak), so needs to be driven with an external transistor.
Use e.g. the tone() command to generate the ~2400Hz.
Leo..

Joprp05

#7
Nov 14, 2017, 01:14 pm Last Edit: Nov 14, 2017, 01:45 pm by Joprp05
It works fine without a transistor though... Just plugged the wires in, used tone() and it worked.
Is it really needed and why of that?

Also, because it is a electromagnetic buzzer, it won't be able to create electricity when it tap it, right?
If you tried various times and it didn't work, take a break, relax and come back later

Wawa

Is it really needed and why of that?

Also, because it is a electromagnetic buzzer, it won't be able to create electricity when it tap it, right?
Yes, needed. That buzzer draws ~100mA peak, and a pin is rated for 40mA absolute max.
Use e.g. a 2N2222. Emitter to ground, base with a ~470ohm resistor to pin, collector to buzzer negative.
Buzzer positive to 5volt, diode (1N4148) across buzzer to protect the transistor.

Not possible to use this buzzer as microphone.
Leo..

Joprp05

Ohhhhh I get it. So it's basically because it draws too much and the transitor amplifies the current, Thank you a lot
If you tried various times and it didn't work, take a break, relax and come back later

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