Hi Everyone,

I`m a chemistry masters student who is currently about to finish his project. I have a problem although, I`m trying to design an driving circuit to drive an Ultrasonic vibration micro nozzle, which will be used to generate droplets on demand. The main porblem I have is that I tried several different circuits and none of them seems to be working. The micronozzle ( product number: M2313500 Prowave electronics) has a Resonant frequency of 143±5 kHz, to achive this frequency I tried using a 555 ic timer (first picture), but sadly it`s not working. I found a different driving circuit which uses coils, and two different kinds of transistors to drive this transducer(second picture), but again it`s also not working. To my suprise I found yet an another driving circuit (third picture) which is also used to drive the very same transducer, but it is entirely different to the others. The weird thing that according to this datasheet the resonant frequency is 135±kHz. I haven`t yet made the third one as I don`t have all the parts for it.
I have no formal education in electronics this is something I picked up lately so I`m not sure if I`m doing something wrong. The circuits that I linked here were all made as a prototypes on separate breadboards ( except number 3, which I have not attempted to build yet)

If anyone could steer me in the right direction it would be much appreciated.
Thanks,
Dan

 

Did the second circuit oscillate?

You could try the 555 oscillator with the output circuit of the bottom circuit which uses an inductor to resonate with the nozzle capacitance in a tank circuit.
Note that the LED appears to be reversed.

You could also try a push-pull emitter follower driver circuit using an NPN and a PNP transistor.
Connect the NPN collector to V+, the PNP collector to common, and the two emitters tied together is the output.
Drive the two bases tied together from the 555 output.

 

The manufacturers circuit in the datasheet should be a very good
choice. Normally this is the "golden" standard for a part, as quite
often the part may have been characterized with their recommended
circuit.


Regards, Dana.

 

Drivers working at 5V and 12V supply will not create much action from the transducer. They like to work at higher voltages if piezoelectric, more current if solenoid types. Check specifications for the transducer requierements.
Is it like a fuel injector type of transducer ?

 

Why the transistor with a 2K collector resistor in the first circuit? The direct output from the 555 would provide more drive current.

What are the specs of the transducer?

Bob

 

Here's the idea of using a transformer. However, the driver used is outdated. You need to use dual gate drivers that contain both direct and inverse outputs.

 

Thanks all for the replies guys. I`m processing all the information you have given me, and will update.

 

Why the transistor with a 2K collector resistor in the first circuit? The direct output from the 555 would provide more drive current.

What are the specs of the transducer?

Bob

I`m not sure why the 2k resistor. I found this circuit online. They used it to drive a transducer with a resonant frequency of 40kHz. I changed the values of R1(2 K ohm), R2( 6 K ohm) and C2 ( 1 nF) so that the output on pin 3 is 144 kHZ, since there`s an equation of f=1.44/(R2+2R1)*C1.
I`m was assuming that the transistor is there to amplify the current ?
I attached the specs of the transducer. My biggest problem is that I have two separate datasheets for the sampe product number, and they differ in the resonant frequency

 

Drivers working at 5V and 12V supply will not create much action from the transducer. They like to work at higher voltages if piezoelectric, more current if solenoid types. Check specifications for the transducer requierements.
Is it like a fuel injector type of transducer ?

So if it won`t work using 5 or 12 V what voltage am I supposed to use. I`m not sure what type. It`s a 50 micron thcik Ni-Co alloy with 7 micron holes on it. I attached the datasheet.

Note: For some reason it has 2 different datasheets, where the product number matches, but the resonant frequency is different.

 

Did the second circuit oscillate?

You could try the 555 oscillator with the output circuit of the bottom circuit which uses an inductor to resonate with the nozzle capacitance in a tank circuit.
Note that the LED appears to be reversed.

You could also try a push-pull emitter follower driver circuit using an NPN and a PNP transistor.
Connect the NPN collector to V+, the PNP collector to common, and the two emitters tied together is the output.
Drive the two bases tied together from the 555 output.

What do you mean by did it oscillate ? Do you mean if i checked it with a led if it`s blinking ?

 

Here's the idea of using a transformer. However, the driver used is outdated. You need to use dual gate drivers that contain both direct and inverse outputs.
View attachment 185642

This looks well complicated for me. Have you got some rescources on this so I can read a bit about it ?

Thanks

 

Here's the circuit without the transformer. Current through a piezo resonator 800 mA. This is much more than with a single-stroke driver.

 

Here is an example with two weekends - a gate driver and a transistor with high current amplification. C2 and C4 are two piezo emitters. The diagram shows the current through the piezoelectric emitters.