piezo transducer; polarity; current

Adam Funk · Mar 21, 2012

I've been playing with a piezo transducer in 556 circuits (at higher
frequencies than with LEDs). The one I'm using is KPE-163, and the
specification says:

Rated Voltage (Vp-p) Max 30
Current Consumption (mA) Max. 10 @10Vp-p, square wave, 4.8Hz

and it has two leads: one black and one red.

I was wondering whether it would work in a double-555 multivibrator
(powered by a 9V battery) described as having push-pull output, and it
does (I think I had some resistance in series just to be careful). So
I wondered whether the implied polarity in the lead colors was
significant.

AFAICT from trying it turned both ways in a single-555 multivibrator
(between the ground and 9V square wave output), I suspect it isn't
actually polarized. Comments?

Also, does the specification mean that the actual current when you
apply 10Vp-p voltage is 10 mA, so (unlike LEDs, for example) it
doesn't need any protective series resistance at that voltage?

(I have 5 of these and they were cheap, so I don't mind burning a
couple out for educational purposes.)

Phil Allison · Mar 22, 2012

"Adam Funk"

I've been playing with a piezo transducer in 556 circuits (at higher
frequencies than with LEDs). The one I'm using is KPE-163, and the
specification says:

** That is a piezo buzzer - it has an electronic circuit that makes the
beep.

Rated Voltage (Vp-p) Max 30
Current Consumption (mA) Max. 10 @10Vp-p, square wave, 4.8Hz

and it has two leads: one black and one red.

** Beep, beep beep beep .....

Jasen Betts · Mar 22, 2012

I've been playing with a piezo transducer in 556 circuits (at higher
frequencies than with LEDs). The one I'm using is KPE-163, and the
specification says:

Rated Voltage (Vp-p) Max 30
Current Consumption (mA) Max. 10 @10Vp-p, square wave, 4.8Hz

is it this one?
http://www.datasheets.org.uk/indexdl/Datasheet-077/DSAE0052603.pdf

and it has two leads: one black and one red.

I was wondering whether it would work in a double-555 multivibrator
(powered by a 9V battery) described as having push-pull output, and it
does (I think I had some resistance in series just to be careful). So
I wondered whether the implied polarity in the lead colors was
significant.

another reason to colour the leads is that if you have two and want the
both to be in phase you can match the leads up

AFAICT from trying it turned both ways in a single-555 multivibrator
(between the ground and 9V square wave output), I suspect it isn't
actually polarized. Comments?

Phil H says thet y can be damaged by prolonged exposue to reverse
polarity. Phil A seems to have the part confused with a different part.

Also, does the specification mean that the actual current when you
apply 10Vp-p voltage is 10 mA, so (unlike LEDs, for example) it
doesn't need any protective series resistance at that voltage?

that's right. it doesn't need any. these devices behave like lossy
capacitors each time they get a voltage change they will only accept a
small amount of charge

(I have 5 of these and they were cheap, so I don't mind burning a
couple out for educational purposes.)

with the 556 you can make a louder noise by using a bridged
configuration:

. . . . . . . .
.O . . .
[. . . .]--+
. . |
. . |
+--------[. .] |
C1 | . . |
|| | . . |
+--||--+ [. 556 .]-----+
| || | . . | |
| | . . | |
| +-----------[. .] | |
| | | . . | |
| | +-[R1]-+ . . | +-----
| | | +-[. .]--+ |
| | | | . . | | to piezo
| | | | . . | |
| | +------|-[. .]-----------
| | | . . | |
| | | . . | |
+---------------[. .]--|--+
| | | . . | |
| | | . . . . . . . . | |
| | | | |
| | +--------------------|--+
| | |
o o------------------------------+
- +
9V battery

or you can produce a varying tone by driving the CV pin
of the cecond astable from the first.

+---------------------------------.
| |
|+ . . . . . . . . |
===== .O . . . |
| C1 [. . . .]---+ |
| . . | |
| . . | |
+--------[. .] | |
| . . | |
| . . | |
| [. 556 .]-----+ |
| . . | | |
| . . | | |
+-----------[. .]--------+
| | . . | |
| | . . | |
| +--[R1]--[. .]--+ |
| | . . | |
| | . . | |
| +--------[. .]--------------+
| . . | | |
| . . | | |
+---------------[. .]--|--+-+-[R2]-+--- +
| | . . | |
| | . . . . . . . . | ===== to piezo
| | | C2 |
| +------------------------------+ +-----------
| | |
+---------------------------------------+
| |
o o
- +
9V battery

R1 47K
C1 10uF
R2 3.3K
C2 10nF

I expect that will make a horrible racket.

Phil Allison · Mar 22, 2012

"John Fields"
"Phil Allison"

"Adam Funk"

** See the OP's post.

" Current Consumption (mA) Max. 10 @10Vp-p, square wave, 4.8Hz "

That error PLUS the pic and description fitted an electronic buzzer.

..... Phil

Adam Funk · Mar 22, 2012

is it this one?
http://www.datasheets.org.uk/indexdl/Datasheet-077/DSAE0052603.pdf

I think so. The data sheet I have is only in English and just has the
information corresponding to parts B, C, & D in that example.

another reason to colour the leads is that if you have two and want the
both to be in phase you can match the leads up

Oh, that's given me an interesting idea to play with.

Thanks for the other information and suggestions!

Adam Funk · Mar 22, 2012

It's a passive ceramic on metal transducer and it's "poled" rather
than polarized.

---
http://www.morganelectroceramics.com/resources/piezo-ceramic-tutorials/piezoelectric-actions/
---

However, it doesn't usually matter in an audio application because
what happens is that if you connect + to red and - to black the piezo
element will flex in one direction, while if you reverse the polarity
it'll flex in the opposite direction.

Interesting, thanks.

Adam Funk · Mar 22, 2012

---
This shows their line of piezo active and passive devices:

http://www.kingstate.com.tw/eng/Pro...bid/185/CatSubTypeId/21/rtab/184/Default.aspx

and this the KPEG163, which I believe is the device you have:

http://www.kingstate.com.tw/eng/Pro...tem/tabid/186/rtab/185/Default.aspx?ItemId=22

Yes, I'm sure that's the one. For some reason the data sheet from RS
calls it "KPE-163" without the "G".

http://uk.rs-online.com/web/p/products/535-8168/

Phil Allison · Mar 22, 2012

"John Fields"
"Phil Allison"
** Irrelevant.

Your link was not available to me.

I found a pic and an ambiguous description.

Did you SEE the error in the OP's post at all ??

...... Phil

Adam Funk · Mar 26, 2012

Did you SEE the error in the OP's post at all ??

What was my error? (The RS website calls it a "Piezo electric
transducer", and the specs were all copied & pasted from the data
sheet.)

ehsjr · Mar 27, 2012

Adam said:
What was my error? (The RS website calls it a "Piezo electric
transducer", and the specs were all copied & pasted from the data
sheet.)

There's a difference in the specs between the datasheet at
the link John Fields posted and the spec you posted:
Your post says "square wave, 4.8Hz"
Datasheet says "square wave, 4.8KHz"

Ed

Adam Funk · Mar 27, 2012

Oops, I just checked the PDF I have from RS, and it must just be a
scan: the text is not copy-and-pastable.

There's a difference in the specs between the datasheet at
the link John Fields posted and the spec you posted:
Your post says "square wave, 4.8Hz"
Datasheet says "square wave, 4.8KHz"

Aha, that's my typing error; the PDF I have does actually say
"4.8KHz". You're right.

piezo transducer; polarity; current

piezo transducer; polarity; current

Adam Funk

Phil Allison

Jasen Betts

Phil Allison

Adam Funk

Adam Funk

Adam Funk

Phil Allison

Adam Funk

ehsjr

Adam Funk

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