Question about piezo buzzers

[Mitch@this_is_not_a_real_]

I want to build a circuit that outputs a 20kHz signal.
I found this:
http://www.geocities.com/tomzi.geo/whistle/whistle.htm

A Radio Shack search yields:
http://tinyurl.com/cvdnr

If a piezo buzzer has a rating of, say 3,200Hz, does that mean its
maximum frequency? Or does it mean its highest output is at that
frequency?

 

[DBLEXPOSURE]

<Mitch@this_is_not_a_real_address.com> wrote in message
news:c76kg191en0tdr29f7fe91ffcnhl80ccee@4ax.com...

I want to build a circuit that outputs a 20kHz signal.
I found this:
http://www.geocities.com/tomzi.geo/whistle/whistle.htm

A Radio Shack search yields:
http://tinyurl.com/cvdnr

If a piezo buzzer has a rating of, say 3,200Hz, does that mean its
maximum frequency? Or does it mean its highest output is at that
frequency?

I think the keyword here is that it is a buzzer. I believe it will only
oscillate at that freq. What you need is a piezo tweeter(speaker). There
are some with high end response up to 40Khz

 

[Michael Black]

"Mitch@this_is_not_a_real_address.com" () writes:

I want to build a circuit that outputs a 20kHz signal.
I found this:
http://www.geocities.com/tomzi.geo/whistle/whistle.htm

A Radio Shack search yields:
http://tinyurl.com/cvdnr

If a piezo buzzer has a rating of, say 3,200Hz, does that mean its
maximum frequency? Or does it mean its highest output is at that
frequency?

A buzzer makes a sound when you apply power. This thing is no different
from the one connected to your front door button. It just needs voltage
and it will "buzz".

The 3.2KHz is the frequency of the buzzer.

There is a "speaker" part in there, along with an oscillator to actually
drive it.

What you would seem to need is merely a speaker, that can handle a high
enough frequency.

They'd be called something like a piezoelectric transducer.

Michael

 

[Jasen Betts]

In article <c76kg191en0tdr29f7fe91ffcnhl80ccee@4ax.com>, Mitch@this_is_not_a_real_address.com wrote:

I want to build a circuit that outputs a 20kHz signal.
I found this:
http://www.geocities.com/tomzi.geo/whistle/whistle.htm

A Radio Shack search yields:
http://tinyurl.com/cvdnr

If a piezo buzzer has a rating of, say 3,200Hz, does that mean its
maximum frequency? Or does it mean its highest output is at that
frequency?

no it means you feed it 12VDC (or whatever the specs say)
and it gives you approx 3200Hz.

if you want a piezo speaker look in the loudspeakers section of the
catalogue.

Most piezo speakers will respond reasonably well up to past 20Khz

Bye.
Jasen

 

[John Fields]

On Thu, 25 Aug 2005 21:33:40 +1200, Jasen Betts
<jasen-b@free.net.nospam.nz> wrote:

In article <c76kg191en0tdr29f7fe91ffcnhl80ccee@4ax.com>, Mitch@this_is_not_a_real_address.com wrote:
I want to build a circuit that outputs a 20kHz signal.
I found this:
http://www.geocities.com/tomzi.geo/whistle/whistle.htm

A Radio Shack search yields:
http://tinyurl.com/cvdnr

If a piezo buzzer has a rating of, say 3,200Hz, does that mean its
maximum frequency? Or does it mean its highest output is at that
frequency?

no it means you feed it 12VDC (or whatever the specs say)
and it gives you approx 3200Hz.

---
Not necessarily. There are some piezo buzzers with integral drive
electronics, and there are which have to be driven externally. The
frequency which is specified for the ones which have to be driven
externally is the resonant frequency of the piezo element and its
housing, and that's the frequency it needs to be driven at to get
the highest SPL out.

--
John Fields
Professional Circuit Designer