# Need help with constructing a piezoelectric circuit

Discussion in 'The Projects Forum' started by chiragdubey94, Dec 22, 2015.

1. ### chiragdubey94 Thread Starter New Member

Dec 22, 2015
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Hello.

I am currently working on a project which requires me to design an electrical circuit.

My aim is to use piezoelectric actuators in parallel (5-10 mm dia), and giving them a voltage of 9V using a signal generator. I want the actuators to vibrate in the 500-800 Hz range.

Keeping in mind that I have to incorporate this in a light weight application, how do I proceed about this?

Thank you.

2. ### DickCappels Moderator

Aug 21, 2008
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It appears that you have already spelled out what you want to do, except the part about it being a light weight application is not clear. It seems you need to connect the transducer to the signal generator and set up the generator to output 9V (RMS?, P-P?) at the desired frequency.

Is there more to your question?

3. ### chiragdubey94 Thread Starter New Member

Dec 22, 2015
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All I want to understand is how to make the circuit, physically (wires and stuff). Being a student of mechanical engineering, I am drawing a blank at that.

The signal generator will be kept outside the 'box', while the circuitry lies inside (transducers and wires).

4. ### Dodgydave AAC Fanatic!

Jun 22, 2012
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So do you need an oscillator of 500-800 hz with a 9V square wave or sinewave output?

For square wave use a 555 timer,
For sinewave use a Wien oscillator.

5. ### DickCappels Moderator

Aug 21, 2008
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Does your signal generator provide a high enough amplitude signal?

If you can provide information on the transducers we can take a stab at it.

6. ### #12 Expert

Nov 30, 2010
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If each transducer has 2 wires, this is how you connect them.

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7. ### chiragdubey94 Thread Starter New Member

Dec 22, 2015
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Wow, so many new things to learn here!

Well, the signal generator isn't a problem. That can be arranged.

The problem lies in circuitry itself. I am unaware of the specs of the transducers. I just know the diameter of them, which is around 5-10 mm. Anything above 9V will damage the transducers.

See, if I have to place the transducers in parallel, preferably an array of 6. You can see a rough sketch. That is the top view. The small circles represent the actuators.

The generator will be placed outside the 'box'. I just need help with figuring out a way to connect it.

Keep in mind that the thickness of the 'box' is not more than 20 mm.

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8. ### DickCappels Moderator

Aug 21, 2008
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I think if you can follow the diagram in #12's post (post #6) you will get what you seek.

An aside, if your signal generator has a DC offset switch, make sure it is off otherwise the transducers may eventually become damaged.

9. ### hp1729 Well-Known Member

Nov 23, 2015
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5 mm to 10 mm in diameter sounds pretty small. Can you provide a data sheet for the parts you are considering?
Something like this?

• ###### cep-1162-515892.pdf
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10. ### hp1729 Well-Known Member

Nov 23, 2015
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Battery powered? How long do you want the batteries to last? Continuous service or intermittent?

11. ### chiragdubey94 Thread Starter New Member

Dec 22, 2015
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No, they aren't battery powered. The application is only producing vibrations in the frequency range of 500-800 Hz, for 9V p-p.

And unfortunately, there are no battery sheets either.

12. ### hp1729 Well-Known Member

Nov 23, 2015
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No batteries???? What powers the oscillator? How much current do the transducers require? We can not do much without specifics of the transducers.

So far we must have a battery that powers an oscillator running at 500 to 800 Hz driving undefined transducers. Are we okay so far?

13. ### Hypatia's Protege Distinguished Member

Mar 1, 2015
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@chiragdubey94

Inasmuch as (owing to their rather high unloaded Q) piezoelectric devices tend to exhibit wide and abrupt impedance variation with frequency -- I strongly advise implementation of a 'brute force' driver topology (e.g. an 'H-Bridge' arrangement, etc...)

Best regards and good luck!
HP

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14. ### chiragdubey94 Thread Starter New Member

Dec 22, 2015
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Update -

So I gathered these piezoelectric discs and took them for a test run.

On a breadboard, I placed four of them in parallel and gave them a frequency in the range of 200 Hz to 30 kHz, for maximum amplitude of the signal generator.

All they did is made a buzzing noise at some frequency, but I couldn't notice any vibration whatsoever. They didn't vibrate like I expected them to.

15. ### Dodgydave AAC Fanatic!

Jun 22, 2012
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What is the voltage amplitude of the signal from the signal generator,, does it work on just one piezo?

16. ### chiragdubey94 Thread Starter New Member

Dec 22, 2015
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well, peak to peak voltage was around maximum value, which is 20 if I am not mistaken.

17. ### Hypatia's Protege Distinguished Member

Mar 1, 2015
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That's about what I'd expect -- What were you expecting? Tactile perception of vibration occurs only at rather low frequencies (< ~ 100Hz)...
Again:
In any case, good design will implement an active driver! --- Signal generators (in the sense used on this thread) are neither designed nor capable of supplying significant power...

Once again, good luck!

Best regards
HP

18. ### chiragdubey94 Thread Starter New Member

Dec 22, 2015
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Okay, let us approach this from another perspective.

Attached here is a figure, a rough sketch. This is how, ideally, I will be placing the actuator/piezoelectric disc. I want it to vibrate at the frequencies 500-800 Hz, no voltage specification at the moment.

Attached here is also the picture of the disc which I used to run the first trial test, which was unsuccessful. I am not sure if I soldered it correctly.

Please, let me know if you can help me.

Thanks a ton. I really need all the help on this.

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19. ### Hypatia's Protege Distinguished Member

Mar 1, 2015
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Respectfully, with what do you require assistance beyond that already offered?

Sincerely, best regards
HP