1:10 Transformer; to match between amplifier and a piezo-disc

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#1
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Hi,

 

I'm trying to connect a 4 ohm's amplifier to a 45 ohm's piezo-disc and I would like to use a 1:10 transformer in between the amplifier and the disc.

 

Does anybody have a suggestion of a good (low cost) 1:10 transformer to use?

 

 

All the Best,

Kim

Last Edited: Thu. Oct 31, 2019 - 06:08 PM
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You do understand that that Piezo is not for audio use, but ultrasound?

 

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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jgmdesign wrote:

You do understand that that Piezo is not for audio use, but ultrasound?

 

Jim

 

 

Yes, but going to use it in the range of 5-15 kHz and at a high voltage.

 

// Kim

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tryx wrote:
Yes, but going to use it in the range of 5-15 kHz and at a high voltage.

 

I couldn't locate a datasheet for the piezo(did not look very hard for it either) but do you mind me asking what the application is?

 

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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Resonant frequency fr: 235 KHz±2%     
 

How are you going to use it at 5-15 KHz, when it is not suited for that range?  You should get an audio piezo! 

 

 the resonant frequency is the operating frequency at which the piezo material vibrates most readily and converts electrical energy into mechanical energy most efficientl

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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avrcandies wrote:

Resonant frequency fr: 235 KHz±2%     
 

How are you going to use it at 5-15 KHz, when it is not suited for that range?  You should get an audio piezo! 

 

 the resonant frequency is the operating frequency at which the piezo material vibrates most readily and converts electrical energy into mechanical energy most efficientl

 

 

Yes, I do know that.

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Does this application have to do with this:

 

https://www.avrfreaks.net/forum/...

 

JIm

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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jgmdesign wrote:

Does this application have to do with this:

 

https://www.avrfreaks.net/forum/...

 

JIm

 

No, it does not.

 

Does anybody might have an answer to the question I posted?

 

 

All the Best,

Kim

Last Edited: Thu. Oct 17, 2019 - 03:42 PM
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tryx wrote:
Does anybody might have an answer to the question I posted?

 

Relax, the other thread bears a lot of similarities, thats why I asked as I also do not want to start another thread on possibly the same topic.

 

Short answer is, you need to look for a transformer that suits your needs.  I suggest yu check out Mouser and Digikey to see if they already have a stock item.  IF not then the next course of action is to contact manufacturers to see if they make one, or wind your own.

 

JIm

 

EDIT:

 

Check here:

https://www.electronicplus.com/c...

 

If you google 4 ohm to 45 ohm audio transformer you will find there are several companies out there that make items close to what you are looking for.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

Last Edited: Thu. Oct 17, 2019 - 04:12 PM
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I'm trying to connect a 4 ohm's amplifier to a 45 ohm's piezo-disc and I would like to use a 1:10 transformer in between the amplifier and the disc.

 

Ok, I was never very good with PNP transistors, or with transformers...

 

That said, isn't a transformer's impedance ratio related to the square of the voltage ratio?

 

If you are estimating a 1:10, (instead of 1: 11), impedance matching ratio, then the voltage ratio, (and turns ratio), would be the square root of 1/10 ratio.

 

Others can correct this if I have it wrong.

 

JC

 

Edit: Typo

Last Edited: Thu. Oct 17, 2019 - 09:25 PM
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DocJC wrote:
Others can correct this if I have it wrong.

No need for correction, you have it right.

A 45 ohm load connected through a 10:1 ratio transformer would present a 0.45 ohm load to the amplifier (assuming said transformer is suitable for the frequencies involved).

Letting the smoke out since 1978

 

 

 

 

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Big ALERT:

 

Your 45 ohm piezo at 235KHz WILL NOT be 45 ohms at 5-15KHz. It is probably WAY different, though nobody here can tell you what it will be. What ever it is,  it won't be the same at 5KHz as it is at 15KHz.

 

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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This piezoelectric driver application note from Accel Instruments has a paragraph on transformer boosting.

 

https://www.accelinstruments.com/Piezo/Piezo-Driver.html

 

Of course the application note is centered around their products: TS200 Modulated Power Supply and TS250 Waveform Amplifier

 

Prices start at $1K.

 

 

 

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Like the others, I think you're using the wrong part for the wrong job. I'd suggest getting piezo tweeter.

 

Anyways, you could use a power transformer 120:12V gives a 10:1 turns ratio.

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Kartman wrote:
I think you're using the wrong part for the wrong job. I'd suggest........

 

The OP has made it very clear:

tryx wrote:
Does anybody might have an answer to the question I posted?

 

The OP does not seem to be interested in anyones opinions regarding the functionality of the components.  Only a matching transformer.

 

I suggest we keep to the topics question of a 1:10 transformer supplier.... smiley

 

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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Thank you Jim! I think one of the links you provided will do "the job".

Last Edited: Thu. Oct 31, 2019 - 06:06 PM
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jgmdesign wrote:

tryx wrote:
Does anybody might have an answer to the question I posted?

 

Relax, the other thread bears a lot of similarities, thats why I asked as I also do not want to start another thread on possibly the same topic.

 

Short answer is, you need to look for a transformer that suits your needs.  I suggest yu check out Mouser and Digikey to see if they already have a stock item.  IF not then the next course of action is to contact manufacturers to see if they make one, or wind your own.

 

JIm

 

EDIT:

 

Check here:

https://www.electronicplus.com/c...

 

If you google 4 ohm to 45 ohm audio transformer you will find there are several companies out there that make items close to what you are looking for.

 

Thank you Jim! I think one of the links you provided will do "the job".

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Thank you Jim! I think one of the links you provided will do "the job".

Last Edited: Thu. Oct 31, 2019 - 06:07 PM
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jgmdesign wrote:

Does this application have to do with this:

 

https://www.avrfreaks.net/forum/...

 

JIm

 

That one was my own "home-test-project" which I did before what I'm doing now. It actually went well in the end. :D

Last Edited: Thu. Oct 31, 2019 - 06:05 PM
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I have told him about resonance frequency, etc. etc. BUT, he will not have it.

You need to have a conversation as to why he isn't listening to your concerns. That is a bad sign!  Remember the challenger disaster?

 

https://www.npr.org/sections/thetwo-way/2016/01/28/464744781/30-years-after-disaster-challenger-engineer-still-blames-himself

 

The night before the launch, Ebeling and four other engineers at NASA contractor Morton Thiokol had tried to stop the launch. Their managers and NASA overruled them.

That night, he told his wife, Darlene, "It's going to blow up."

When Challenger exploded 73 seconds after liftoff, Ebeling and his colleagues sat stunned in a conference room at Thiokol's headquarters outside Brigham City, Utah. They watched the spacecraft explode on a giant television screen and they knew exactly what had happened.

 

https://www.npr.org/sections/thetwo-way/2012/02/06/146490064/remembering-roger-boisjoly-he-tried-to-stop-shuttle-challenger-launch

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Fri. Oct 18, 2019 - 04:53 PM
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I think the boss man is trying to get you to think and solve a problem. If you have some engineering background, then this might make sense. I was mentoring a graduate and i would always push him to fall back on the theory he’d learnt.
The conversation would go something like this:

S: hey boss, i’m not getting much output from this piezo
M: what is the impedance of the amp and the piezo?
S: four ohms and 45 ohms
M: sounds like you need a transformer!
S: where do i get one of these?
M: how about doing some calculations first?
S: how do i calculate it?
Then I’d put my grumpy old man hat on and say “in my day, i’d find my old textbook and give it a read - you have Google”

The moral of the story is the transformer you ‘think’ you want is not the one you ‘need’. I suggested a power transformer as there might be something in the junk box or cheaply and easily obtained. Say 120:12V 1A. Its not necessarily the solution, but it something you can try.
Having looked inside a cheapy piezo siren, the solution is usually an ‘auto transformer’ with a ferrite core.