# Need help with constructing a piezoelectric circuit

#### chiragdubey94

Joined Dec 22, 2015
7
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.

#### DickCappels

Joined Aug 21, 2008
10,104
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?

#### chiragdubey94

Joined Dec 22, 2015
7

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).

#### Dodgydave

Joined Jun 22, 2012
11,149
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.

#### DickCappels

Joined Aug 21, 2008
10,104
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.

#### #12

Joined Nov 30, 2010
18,224
If each transducer has 2 wires, this is how you connect them.

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#### chiragdubey94

Joined Dec 22, 2015
7
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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#### DickCappels

Joined Aug 21, 2008
10,104
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.

#### hp1729

Joined Nov 23, 2015
2,304
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?
We are looking at 7 mA per device. We could drive a bunch of them with a 555.

Thank you.
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?

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#### hp1729

Joined Nov 23, 2015
2,304
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?
Battery powered? How long do you want the batteries to last? Continuous service or intermittent?

#### chiragdubey94

Joined Dec 22, 2015
7
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.

#### hp1729

Joined Nov 23, 2015
2,304
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.
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?

#### Hypatia's Protege

Joined Mar 1, 2015
3,226
@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

#### chiragdubey94

Joined Dec 22, 2015
7
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.

#### Dodgydave

Joined Jun 22, 2012
11,149
What is the voltage amplitude of the signal from the signal generator,, does it work on just one piezo?

#### chiragdubey94

Joined Dec 22, 2015
7
well, peak to peak voltage was around maximum value, which is 20 if I am not mistaken.

#### Hypatia's Protege

Joined Mar 1, 2015
3,226
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.
That's about what I'd expect -- What were you expecting? Tactile perception of vibration occurs only at rather low frequencies (< ~ 100Hz)...
Again:
@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...)
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

#### chiragdubey94

Joined Dec 22, 2015
7
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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#### Hypatia's Protege

Joined Mar 1, 2015
3,226
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.
Respectfully, with what do you require assistance beyond that already offered?

Sincerely, best regards
HP